Enter your Sign on user name and password.

Forgot password?
Sign In | Subscribe
Start learning today, and be successful in your academic & professional career. Start Today!

Use Chrome browser to play professor video
Dr. Laurie Starkey

Dr. Laurie Starkey

Ketones

Slide Duration:

Table of Contents

I. Introduction to Organic Molecules
Introduction and Drawing Structures

49m 51s

Intro
0:00
Organic Chemistry
0:07
Organic
0:08
Inorganic
0:26
Examples of Organic Compounds
1:16
Review Some Chemistry Basics
5:23
Electrons
5:42
Orbitals (s,p,d,f)
6:12
Review Some Chemistry Basics
7:35
Elements & Noble Gases
7:36
Atom & Valance Shell
8:47
Review Some Chemistry Basics
11:33
Electronegative Elements
11:34
Which Is More Electronegative, C or N?
13:45
Ionic & Covalent Bonds
14:07
Ionic Bonds
14:08
Covalent Bonds
16:17
Polar Covalent Bonds
19:35
Polar Covalent Bonds & Electronegativities
19:37
Polarity of Molecules
22:56
Linear molecule
23:07
Bent Molecule
23:53
No Polar Bonds
24:21
Ionic
24:52
Line Drawings
26:36
Line Drawing Overview
26:37
Line Drawing: Example 1
27:12
Line Drawing: Example 2
29:14
Line Drawing: Example 3
29:51
Line Drawing: Example 4
30:34
Line Drawing: Example 5
31:21
Line Drawing: Example 6
32:41
Diversity of Organic Compounds
33:57
Diversity of Organic Compounds
33:58
Diversity of Organic Compounds, cont.
39:16
Diversity of Organic Compounds, cont.
39:17
Examples of Polymers
45:26
Examples of Polymers
45:27
Lewis Structures & Resonance

44m 25s

Intro
0:00
Lewis Structures
0:08
How to Draw a Lewis Structure
0:09
Examples
2:20
Lewis Structures
6:25
Examples: Lewis Structure
6:27
Determining Formal Charges
8:48
Example: Determining Formal Charges for Carbon
10:11
Example: Determining Formal Charges for Oxygen
11:02
Lewis Structures
12:08
Typical, Stable Bonding Patterns: Hydrogen
12:11
Typical, Stable Bonding Patterns: Carbon
12:58
Typical, Stable Bonding Patterns: Nitrogen
13:25
Typical, Stable Bonding Patterns: Oxygen
13:54
Typical, Stable Bonding Patterns: Halogen
14:16
Lewis Structure Example
15:17
Drawing a Lewis Structure for Nitric Acid
15:18
Resonance
21:58
Definition of Resonance
22:00
Delocalization
22:07
Hybrid Structure
22:38
Rules for Estimating Stability of Resonance Structures
26:04
Rule Number 1: Complete Octets
26:10
Rule Number 2: Separation of Charge
28:13
Rule Number 3: Negative and Positive Charges
30:02
Rule Number 4: Equivalent
31:06
Looking for Resonance
32:09
Lone Pair Next to a p Bond
32:10
Vacancy Next to a p Bond
33:53
p Bond Between Two Different Elements
35:00
Other Type of Resonance: Benzene
36:06
Resonance Example
37:29
Draw and Rank Resonance Forms
37:30
Acid-Base Reactions

1h 7m 46s

Intro
0:00
Acid-Base Reactions
0:07
Overview
0:08
Lewis Acid and Lewis Base
0:30
Example 1: Lewis Acid and Lewis Base
1:53
Example 2: Lewis Acid and Lewis Base
3:04
Acid-base Reactions
4:54
Bonsted-Lowry Acid and Bonsted-Lowry Base
4:56
Proton Transfer Reaction
5:36
Acid-Base Equilibrium
8:14
Two Acids in Competition = Equilibrium
8:15
Example: Which is the Stronger Acid?
8:40
Periodic Trends for Acidity
12:40
Across Row
12:41
Periodic Trends for Acidity
19:48
Energy Diagram
19:50
Periodic Trends for Acidity
21:28
Down a Family
21:29
Inductive Effects on Acidity
25:52
Example: Which is the Stronger Acid?
25:54
Other Electron-Withdrawing Group (EWG)
30:37
Inductive Effects on Acidity
32:55
Inductive Effects Decrease with Distance
32:56
Resonance Effects on Acidity
36:35
Examples of Resonance Effects on Acidity
36:36
Resonance Effects on Acidity
41:15
Small and Large Amount of Resonance
41:17
Acid-Base Example
43:10
Which is Most Acidic? Which is the Least Acidic?
43:12
Acid-Base Example
49:26
Which is the Stronger Base?
49:27
Acid-Base Example
53:58
Which is the Strongest Base?
53:59
Common Acids/Bases
1:00:45
Common Acids/Bases
1:00:46
Example: Determine the Direction of Equilibrium
1:04:51
Structures and Properties of Organic Molecules

1h 23m 35s

Intro
0:00
Orbitals and Bonding
0:20
Atomic Orbitals (AO)
0:21
Molecular Orbitals (MO)
1:46
Definition of Molecular Orbitals
1:47
Example 1: Formation of Sigma Bond and Molecular Orbitals
2:20
Molecular Orbitals (MO)
5:25
Example 2: Formation of Pi Bond
5:26
Overlapping E Levels of MO's
7:28
Energy Diagram
7:29
Electronic Transitions
9:18
Electronic Transitions
9:23
Hybrid Orbitals
12:04
Carbon AO
12:06
Hybridization
13:51
Hybrid Orbitals
15:02
Examples of Hybrid Orbitals
15:05
Example: Assign Hybridization
20:31
3-D Sketches
24:05
sp3
24:24
sp2
25:28
sp
27:41
3-D Sketches of Molecules
29:07
3-D Sketches of Molecules 1
29:08
3-D Sketches of Molecules 2
32:29
3-D Sketches of Molecules 3
35:36
3D Sketch
37:20
How to Draw 3D Sketch
37:22
Example 1: Drawing 3D Sketch
37:50
Example 2: Drawing 3D Sketch
43:04
Hybridization and Resonance
46:06
Example: Hybridization and Resonance
46:08
Physical Properties
49:55
Water Solubility, Boiling Points, and Intermolecular Forces
49:56
Types of 'Nonbonding' Interactions
51:47
Dipole-Dipole
52:37
Definition of Dipole-Dipole
52:39
Example: Dipole-Dipole Bonding
53:27
Hydrogen Bonding
57:14
Definition of Hydrogen Bonding
57:15
Example: Hydrogen Bonding
58:05
Van Der Waals/ London Forces
1:03:11
Van Der Waals/ London Forces
1:03:12
Example: Van Der Waals/ London Forces
1:04:59
Water Solubility
1:08:32
Water Solubility
1:08:34
Example: Water Solubility
1:09:05
Example: Acetone
1:11:29
Isomerism
1:13:51
Definition of Isomers
1:13:53
Constitutional Isomers and Example
1:14:17
Stereoisomers and Example
1:15:34
Introduction to Functional Groups
1:17:06
Functional Groups: Example, Abbreviation, and Name
1:17:07
Introduction to Functional Groups
1:20:48
Functional Groups: Example, Abbreviation, and Name
1:20:49
Alkane Structures

1h 13m 38s

Intro
0:00
Nomenclature of Alkanes
0:12
Nomenclature of Alkanes and IUPAC Rules
0:13
Examples: Nomenclature of Alkanes
4:38
Molecular Formula and Degrees of Unsaturation (DU)
17:24
Alkane Formula
17:25
Example: Heptane
17:58
Why '2n+2' Hydrogens?
18:35
Adding a Ring
19:20
Adding a p Bond
19:42
Example 1: Determine Degrees of Unsaturation (DU)
20:17
Example 2: Determine Degrees of Unsaturation (DU)
21:35
Example 3: Determine DU of Benzene
23:30
Molecular Formula and Degrees of Unsaturation (DU)
24:41
Example 4: Draw Isomers
24:42
Physical properties of Alkanes
29:17
Physical properties of Alkanes
29:18
Conformations of Alkanes
33:40
Conformational Isomers
33:42
Conformations of Ethane: Eclipsed and Staggered
34:40
Newman Projection of Ethane
36:15
Conformations of Ethane
40:38
Energy and Degrees Rotated Diagram
40:41
Conformations of Butane
42:28
Butane
42:29
Newman Projection of Butane
43:35
Conformations of Butane
44:25
Energy and Degrees Rotated Diagram
44:30
Cycloalkanes
51:26
Cyclopropane and Cyclobutane
51:27
Cyclopentane
53:56
Cycloalkanes
54:56
Cyclohexane: Chair, Boat, and Twist Boat Conformations
54:57
Drawing a Cyclohexane Chair
57:58
Drawing a Cyclohexane Chair
57:59
Newman Projection of Cyclohexane
1:02:14
Cyclohexane Chair Flips
1:04:06
Axial and Equatorial Groups
1:04:10
Example: Chair Flip on Methylcyclohexane
1:06:44
Cyclohexane Conformations Example
1:09:01
Chair Conformations of cis-1-t-butyl-4-methylcyclohexane
1:09:02
Stereochemistry

1h 40m 54s

Intro
0:00
Stereochemistry
0:10
Isomers
0:11
Stereoisomer Examples
1:30
Alkenes
1:31
Cycloalkanes
2:35
Stereoisomer Examples
4:00
Tetrahedral Carbon: Superimposable (Identical)
4:01
Tetrahedral Carbon: Non-Superimposable (Stereoisomers)
5:18
Chirality
7:18
Stereoisomers
7:19
Chiral
8:05
Achiral
8:29
Example: Achiral and Chiral
8:45
Chirality
20:11
Superimposable, Non-Superimposable, Chiral, and Achiral
20:12
Nomenclature
23:00
Cahn-Ingold-Prelog Rules
23:01
Nomenclature
29:39
Example 1: Nomenclature
29:40
Example 2: Nomenclature
31:49
Example 3: Nomenclature
33:24
Example 4: Nomenclature
35:39
Drawing Stereoisomers
36:58
Drawing (S)-2-bromopentane
36:59
Drawing the Enantiomer of (S)-2-bromopentane: Method 1
38:47
Drawing the Enantiomer of (S)-2-bromopentane: Method 2
39:35
Fischer Projections
41:47
Definition of Fischer Projections
41:49
Drawing Fischer Projection
43:43
Use of Fisher Projection: Assigning Configuration
49:13
Molecules with Two Chiral Carbons
51:49
Example A
51:42
Drawing Enantiomer of Example A
53:26
Fischer Projection of A
54:25
Drawing Stereoisomers, cont.
59:40
Drawing Stereoisomers Examples
59:41
Diastereomers
1:01:48
Drawing Stereoisomers
1:06:37
Draw All Stereoisomers of 2,3-dichlorobutane
1:06:38
Molecules with Two Chiral Centers
1:10:22
Draw All Stereoisomers of 2,3-dichlorobutane, cont.
1:10:23
Optical Activity
1:14:10
Chiral Molecules
1:14:11
Angle of Rotation
1:14:51
Achiral Species
1:16:46
Physical Properties of Stereoisomers
1:17:11
Enantiomers
1:17:12
Diastereomers
1:18:01
Example
1:18:26
Physical Properties of Stereoisomers
1:23:05
When Do Enantiomers Behave Differently?
1:23:06
Racemic Mixtures
1:28:18
Racemic Mixtures
1:28:21
Resolution
1:29:52
Unequal Mixtures of Enantiomers
1:32:54
Enantiomeric Excess (ee)
1:32:55
Unequal Mixture of Enantiomers
1:34:43
Unequal Mixture of Enantiomers
1:34:44
Example: Finding ee
1:36:38
Example: Percent of Composition
1:39:46
II. Understanding Organic Reactions
Nomenclature

1h 53m 47s

Intro
0:00
Cycloalkane Nomenclature
0:17
Cycloalkane Nomenclature and Examples
0:18
Alkene Nomenclature
6:28
Alkene Nomenclature and Examples
6:29
Alkene Nomenclature: Stereochemistry
15:07
Alkenes With Two Groups: Cis & Trans
15:08
Alkenes With Greater Than Two Groups: E & Z
18:26
Alkyne Nomenclature
24:46
Alkyne Nomenclature and Examples
24:47
Alkane Has a Higher Priority Than Alkyne
28:25
Alcohol Nomenclature
29:24
Alcohol Nomenclature and Examples
29:25
Alcohol FG Has Priority Over Alkene/yne
33:41
Ether Nomenclature
36:32
Ether Nomenclature and Examples
36:33
Amine Nomenclature
42:59
Amine Nomenclature and Examples
43:00
Amine Nomenclature
49:45
Primary, Secondary, Tertiary, Quaternary Salt
49:46
Aldehyde Nomenclature
51:37
Aldehyde Nomenclature and Examples
51:38
Ketone Nomenclature
58:43
Ketone Nomenclature and Examples
58:44
Aromatic Nomenclature
1:05:02
Aromatic Nomenclature and Examples
1:05:03
Aromatic Nomenclature, cont.
1:09:09
Ortho, Meta, and Para
1:09:10
Aromatic Nomenclature, cont.
1:13:27
Common Names for Simple Substituted Aromatic Compounds
1:13:28
Carboxylic Acid Nomenclature
1:16:35
Carboxylic Acid Nomenclature and Examples
1:16:36
Carboxylic Acid Derivatives
1:22:28
Carboxylic Acid Derivatives
1:22:42
General Structure
1:23:10
Acid Halide Nomenclature
1:24:48
Acid Halide Nomenclature and Examples
1:24:49
Anhydride Nomenclature
1:28:10
Anhydride Nomenclature and Examples
1:28:11
Ester Nomenclature
1:32:50
Ester Nomenclature
1:32:51
Carboxylate Salts
1:38:51
Amide Nomenclature
1:40:02
Amide Nomenclature and Examples
1:40:03
Nitrile Nomenclature
1:45:22
Nitrile Nomenclature and Examples
1:45:23
Chemical Reactions

51m 1s

Intro
0:00
Chemical Reactions
0:06
Reactants and Products
0:07
Thermodynamics
0:50
Equilibrium Constant
1:06
Equation
2:35
Organic Reaction
3:05
Energy vs. Progress of Rxn Diagrams
3:48
Exothermic Reaction
4:02
Endothermic Reaction
6:54
Estimating ΔH rxn
9:15
Bond Breaking
10:03
Bond Formation
10:25
Bond Strength
11:35
Homolytic Cleavage
11:59
Bond Dissociation Energy (BDE) Table
12:29
BDE for Multiple Bonds
14:32
Examples
17:35
Kinetics
20:35
Kinetics
20:36
Examples
21:49
Reaction Rate Variables
23:15
Reaction Rate Variables
23:16
Increasing Temperature, Increasing Rate
24:08
Increasing Concentration, Increasing Rate
25:39
Decreasing Energy of Activation, Increasing Rate
27:49
Two-Step Mechanisms
30:06
E vs. POR Diagram (2-step Mechanism)
30:07
Reactive Intermediates
33:03
Reactive Intermediates
33:04
Example: A Carbocation
35:20
Carbocation Stability
37:24
Relative Stability of Carbocation
37:25
Alkyl groups and Hyperconjugation
38:45
Carbocation Stability
41:57
Carbocation Stabilized by Resonance: Allylic
41:58
Carbocation Stabilized by Resonance: Benzylic
42:59
Overall Carbocation Stability
44:05
Free Radicals
45:05
Definition and Examples of Free Radicals
45:06
Radical Mechanisms
49:40
Example: Regular Arrow
49:41
Example: Fish-Hook Arrow
50:17
Free Radical Halogenation

26m 23s

Intro
0:00
Free Radical Halogenation
0:06
Free Radical Halogenation
0:07
Mechanism: Initiation
1:27
Mechanism: Propagation Steps
2:21
Free Radical Halogenation
5:33
Termination Steps
5:36
Example 1: Terminations Steps
6:00
Example 2: Terminations Steps
6:18
Example 3: Terminations Steps
7:43
Example 4: Terminations Steps
8:04
Regiochemistry of Free Radical Halogenation
9:32
Which Site/Region Reacts and Why?
9:34
Bromination and Rate of Reaction
14:03
Regiochemistry of Free Radical Halogenation
14:30
Chlorination
14:31
Why the Difference in Selectivity?
19:58
Allylic Halogenation
20:53
Examples of Allylic Halogenation
20:55
Substitution Reactions

1h 48m 5s

Intro
0:00
Substitution Reactions
0:06
Substitution Reactions Example
0:07
Nucleophile
0:39
Electrophile
1:20
Leaving Group
2:56
General Reaction
4:13
Substitution Reactions
4:43
General Reaction
4:46
Substitution Reaction Mechanisms: Simultaneous
5:08
Substitution Reaction Mechanisms: Stepwise
5:34
SN2 Substitution
6:21
Example of SN2 Mechanism
6:22
SN2 Kinetics
7:58
Rate of SN2
9:10
Sterics Affect Rate of SN2
9:12
Rate of SN2 (By Type of RX)
14:13
SN2: E vs. POR Diagram
17:26
E vs. POR Diagram
17:27
Transition State (TS)
18:24
SN2 Transition State, Kinetics
20:58
SN2 Transition State, Kinetics
20:59
Hybridization of TS Carbon
21:57
Example: Allylic LG
23:34
Stereochemistry of SN2
25:46
Backside Attack and Inversion of Stereochemistry
25:48
SN2 Summary
29:56
Summary of SN2
29:58
Predict Products (SN2)
31:42
Example 1: Predict Products
31:50
Example 2: Predict Products
33:38
Example 3: Predict Products
35:11
Example 4: Predict Products
36:11
Example 5: Predict Products
37:32
SN1 Substitution Mechanism
41:52
Is This Substitution? Could This Be an SN2 Mechanism?
41:54
SN1 Mechanism
43:50
Two Key Steps: 1. Loss of LG
43:53
Two Key Steps: 2. Addition of nu
45:11
SN1 Kinetics
47:17
Kinetics of SN1
47:18
Rate of SN1 (By RX type)
48:44
SN1 E vs. POR Diagram
49:49
E vs. POR Diagram
49:51
First Transition Stage (TS-1)
51:48
Second Transition Stage (TS-2)
52:56
Stereochemistry of SN1
53:44
Racemization of SN1 and Achiral Carbocation Intermediate
53:46
Example
54:29
SN1 Summary
58:25
Summary of SN1
58:26
SN1 or SN2 Mechanisms?
1:00:40
Example 1: SN1 or SN2 Mechanisms
1:00:42
Example 2: SN1 or SN2 Mechanisms
1:03:00
Example 3: SN1 or SN2 Mechanisms
1:04:06
Example 4: SN1 or SN2 Mechanisms
1:06:17
SN1 Mechanism
1:09:12
Three Steps of SN1 Mechanism
1:09:13
SN1 Carbocation Rearrangements
1:14:50
Carbocation Rearrangements Example
1:14:51
SN1 Carbocation Rearrangements
1:20:46
Alkyl Groups Can Also Shift
1:20:48
Leaving Groups
1:24:26
Leaving Groups
1:24:27
Forward or Reverse Reaction Favored?
1:26:00
Leaving Groups
1:29:59
Making poor LG Better: Method 1
1:30:00
Leaving Groups
1:34:18
Making poor LG Better: Tosylate (Method 2)
1:34:19
Synthesis Problem
1:38:15
Example: Provide the Necessary Reagents
1:38:16
Nucleophilicity
1:41:10
What Makes a Good Nucleophile?
1:41:11
Nucleophilicity
1:44:45
Periodic Trends: Across Row
1:44:47
Periodic Trends: Down a Family
1:46:46
Elimination Reactions

1h 11m 43s

Intro
0:00
Elimination Reactions: E2 Mechanism
0:06
E2 Mechanism
0:08
Example of E2 Mechanism
1:01
Stereochemistry of E2
4:48
Anti-Coplanar & Anti-Elimination
4:50
Example 1: Stereochemistry of E2
5:34
Example 2: Stereochemistry of E2
10:39
Regiochemistry of E2
13:04
Refiochemistry of E2 and Zaitsev's Rule
13:05
Alkene Stability
17:39
Alkene Stability
19:20
Alkene Stability Examples
19:22
Example 1: Draw Both E2 Products and Select Major
21:57
Example 2: Draw Both E2 Products and Select Major
25:02
SN2 Vs. E2 Mechanisms
29:06
SN2 Vs. E2 Mechanisms
29:07
When Do They Compete?
30:34
SN2 Vs. E2 Mechanisms
31:23
Compare Rates
31:24
SN2 Vs. E2 Mechanisms
36:34
t-BuBr: What If Vary Base?
36:35
Preference for E2 Over SN2 (By RX Type)
40:42
E1 Elimination Mechanism
41:51
E1 - Elimination Unimolecular
41:52
E1 Mechanism: Step 1
44:14
E1 Mechanism: Step 2
44:48
E1 Kinetics
46:58
Rate = k[RCI]
47:00
E1 Rate (By Type of Carbon Bearing LG)
48:31
E1 Stereochemistry
49:49
Example 1: E1 Stereochemistry
49:51
Example 2: E1 Stereochemistry
52:31
Carbocation Rearrangements
55:57
Carbocation Rearrangements
56:01
Product Mixtures
57:20
Predict the Product: SN2 vs. E2
59:58
Example 1: Predict the Product
1:00:00
Example 2: Predict the Product
1:02:10
Example 3: Predict the Product
1:04:07
Predict the Product: SN2 vs. E2
1:06:06
Example 4: Predict the Product
1:06:07
Example 5: Predict the Product
1:07:29
Example 6: Predict the Product
1:07:51
Example 7: Predict the Product
1:09:18
III. Alkanes, Alkenes, & Alkynes
Alkenes

36m 39s

Intro
0:00
Alkenes
0:12
Definition and Structure of Alkenes
0:13
3D Sketch of Alkenes
1:53
Pi Bonds
3:48
Alkene Stability
4:57
Alkyl Groups Attached
4:58
Trans & Cis
6:20
Alkene Stability
8:42
Pi Bonds & Conjugation
8:43
Bridgehead Carbons & Bredt's Rule
10:22
Measuring Stability: Hydrogenation Reaction
11:40
Alkene Synthesis
12:01
Method 1: E2 on Alkyl Halides
12:02
Review: Stereochemistry
16:17
Review: Regiochemistry
16:50
Review: SN2 vs. E2
17:34
Alkene Synthesis
18:57
Method 2: Dehydration of Alcohols
18:58
Mechanism
20:08
Alkene Synthesis
23:26
Alcohol Dehydration
23:27
Example 1: Comparing Strong Acids
26:59
Example 2: Mechanism for Dehydration Reaction
29:00
Example 3: Transform
32:50
Reactions of Alkenes

2h 8m 44s

Intro
0:00
Reactions of Alkenes
0:05
Electrophilic Addition Reaction
0:06
Addition of HX
2:02
Example: Regioselectivity & 2 Steps Mechanism
2:03
Markovnikov Addition
5:30
Markovnikov Addition is Favored
5:31
Graph: E vs. POR
6:33
Example
8:29
Example: Predict and Consider the Stereochemistry
8:30
Hydration of Alkenes
12:31
Acid-catalyzed Addition of Water
12:32
Strong Acid
14:20
Hydration of Alkenes
15:20
Acid-catalyzed Addition of Water: Mechanism
15:21
Hydration vs. Dehydration
19:51
Hydration Mechanism is Exact Reverse of Dehydration
19:52
Example
21:28
Example: Hydration Reaction
21:29
Alternative 'Hydration' Methods
25:26
Oxymercuration-Demercuration
25:27
Oxymercuration Mechanism
28:55
Mechanism of Oxymercuration
28:56
Alternative 'Hydration' Methods
30:51
Hydroboration-Oxidation
30:52
Hydroboration Mechanism
33:22
1-step (concerted)
33:23
Regioselective
34:45
Stereoselective
35:30
Example
35:58
Example: Hydroboration-Oxidation
35:59
Example
40:42
Example: Predict the Major Product
40:43
Synthetic Utility of 'Alternate' Hydration Methods
44:36
Example: Synthetic Utility of 'Alternate' Hydration Methods
44:37
Flashcards
47:28
Tips On Using Flashcards
47:29
Bromination of Alkenes
49:51
Anti-Addition of Br₂
49:52
Bromination Mechanism
53:16
Mechanism of Bromination
53:17
Bromination Mechanism
55:42
Mechanism of Bromination
55:43
Bromination: Halohydrin Formation
58:54
Addition of other Nu: to Bromonium Ion
58:55
Mechanism
1:00:08
Halohydrin: Regiochemistry
1:03:55
Halohydrin: Regiochemistry
1:03:56
Bromonium Ion Intermediate
1:04:26
Example
1:09:28
Example: Predict Major Product
1:09:29
Example Cont.
1:10:59
Example: Predict Major Product Cont.
1:11:00
Catalytic Hydrogenation of Alkenes
1:13:19
Features of Catalytic Hydrogenation
1:13:20
Catalytic Hydrogenation of Alkenes
1:14:48
Metal Surface
1:14:49
Heterogeneous Catalysts
1:15:29
Homogeneous Catalysts
1:16:08
Catalytic Hydrogenation of Alkenes
1:17:44
Hydrogenation & Pi Bond Stability
1:17:45
Energy Diagram
1:19:22
Catalytic Hydrogenation of Dienes
1:20:40
Hydrogenation & Pi Bond Stability
1:20:41
Energy Diagram
1:23:31
Example
1:24:14
Example: Predict Product
1:24:15
Oxidation of Alkenes
1:27:21
Redox Review
1:27:22
Epoxide
1:30:26
Diol (Glycol)
1:30:54
Ketone/ Aldehyde
1:31:13
Epoxidation
1:32:08
Epoxidation
1:32:09
General Mechanism
1:36:32
Alternate Epoxide Synthesis
1:37:38
Alternate Epoxide Synthesis
1:37:39
Dihydroxylation
1:41:10
Dihydroxylation
1:41:12
General Mechanism (Concerted Via Cycle Intermediate)
1:42:38
Ozonolysis
1:44:22
Ozonolysis: Introduction
1:44:23
Ozonolysis: Is It Good or Bad?
1:45:05
Ozonolysis Reaction
1:48:54
Examples
1:51:10
Example 1: Ozonolysis
1:51:11
Example
1:53:25
Radical Addition to Alkenes
1:55:05
Recall: Free-Radical Halogenation
1:55:15
Radical Mechanism
1:55:45
Propagation Steps
1:58:01
Atom Abstraction
1:58:30
Addition to Alkene
1:59:11
Radical Addition to Alkenes
1:59:54
Markovnivok (Electrophilic Addition) & anti-Mark. (Radical Addition)
1:59:55
Mechanism
2:01:03
Alkene Polymerization
2:05:35
Example: Alkene Polymerization
2:05:36
Alkynes

1h 13m 19s

Intro
0:00
Structure of Alkynes
0:04
Structure of Alkynes
0:05
3D Sketch
2:30
Internal and Terminal
4:03
Reductions of Alkynes
4:36
Catalytic Hydrogenation
4:37
Lindlar Catalyst
5:25
Reductions of Alkynes
7:24
Dissolving Metal Reduction
7:25
Oxidation of Alkynes
9:24
Ozonolysis
9:25
Reactions of Alkynes
10:56
Addition Reactions: Bromination
10:57
Addition of HX
12:24
Addition of HX
12:25
Addition of HX
13:36
Addition of HX: Mechanism
13:37
Example
17:38
Example: Transform
17:39
Hydration of Alkynes
23:35
Hydration of Alkynes
23:36
Hydration of Alkynes
26:47
Hydration of Alkynes: Mechanism
26:49
'Hydration' via Hydroboration-Oxidation
32:57
'Hydration' via Hydroboration-Oxidation
32:58
Disiamylborane
33:28
Hydroboration-Oxidation Cont.
34:25
Alkyne Synthesis
36:17
Method 1: Alkyne Synthesis By Dehydrohalogenation
36:19
Alkyne Synthesis
39:06
Example: Transform
39:07
Alkyne Synthesis
41:21
Method 2 & Acidity of Alkynes
41:22
Conjugate Bases
43:06
Preparation of Acetylide Anions
49:55
Preparation of Acetylide Anions
49:57
Alkyne Synthesis
53:40
Synthesis Using Acetylide Anions
53:41
Example 1: Transform
57:04
Example 2: Transform
1:01:07
Example 3: Transform
1:06:22
IV. Alcohols
Alcohols, Part I

59m 52s

Intro
0:00
Alcohols
0:11
Attributes of Alcohols
0:12
Boiling Points
2:00
Water Solubility
5:00
Water Solubility (Like Dissolves Like)
5:01
Acidity of Alcohols
9:39
Comparison of Alcohols Acidity
9:41
Preparation of Alkoxides
13:03
Using Strong Base Like Sodium Hydride
13:04
Using Redox Reaction
15:36
Preparation of Alkoxides
17:41
Using K°
17:42
Phenols Are More Acidic Than Other Alcohols
19:51
Synthesis of Alcohols, ROH
21:43
Synthesis of Alcohols from Alkyl Halides, RX (SN2 or SN1)
21:44
Synthesis of Alcohols, ROH
25:08
Unlikely on 2° RX (E2 Favored)
25:09
Impossible on 3° RX (E2) and Phenyl/Vinyl RX (N/R)
25:47
Synthesis of Alcohols, ROH
26:26
SN1 with H₂O 'Solvolysis' or 'Hydrolysis'
26:27
Carbocation Can Rearrange
29:00
Synthesis of Alcohols, ROH
30:08
Synthesis of Alcohols From Alkenes: Hydration
30:09
Synthesis of Alcohols From Alkenes: Oxidation/Diol
32:20
Synthesis of Alcohols, ROH
33:14
Synthesis of Alcohols From Ketones and Aldehydes
33:15
Organometallic Reagents: Preparation
37:03
Grignard (RMgX)
37:04
Organolithium (Rli)
40:03
Organometallic Reagents: Reactions
41:45
Reactions of Organometallic Reagents
41:46
Organometallic Reagents: Reactions as Strong Nu:
46:40
Example 1: Reactions as Strong Nu:
46:41
Example 2: Reactions as Strong Nu:
48:57
Hydride Nu:
50:52
Hydride Nu:
50:53
Examples
53:34
Predict 1
53:35
Predict 2
54:45
Examples
56:43
Transform
56:44
Provide Starting Material
58:18
Alcohols, Part II

45m 35s

Intro
0:00
Oxidation Reactions
0:08
Oxidizing Agents: Jones, PCC, Swern
0:09
'Jones' Oxidation
0:43
Example 1: Predict Oxidation Reactions
2:29
Example 2: Predict Oxidation Reactions
3:00
Oxidation Reactions
4:11
Selective Oxidizing Agents (PCC and Swern)
4:12
PCC (Pyridiniym Chlorochromate)
5:10
Swern Oxidation
6:05
General [ox] Mechanism
8:32
General [ox] Mechanism
8:33
Oxidation of Alcohols
10:11
Example 1: Oxidation of Alcohols
10:12
Example 2: Oxidation of Alcohols
11:20
Example 3: Oxidation of Alcohols
11:46
Example
13:09
Predict: PCC Oxidation Reactions
13:10
Tosylation of Alcohols
15:22
Introduction to Tosylation of Alcohols
15:23
Example
21:08
Example: Tosylation of Alcohols
21:09
Reductions of Alcohols
23:39
Reductions of Alcohols via SN2 with Hydride
24:22
Reductions of Alcohols via Dehydration
27:12
Conversion of Alcohols to Alkyl Halides
30:12
Conversion of Alcohols to Alkyl Halides via Tosylate
30:13
Conversion of Alcohols to Alkyl Halides
31:17
Using HX
31:18
Mechanism
32:09
Conversion of Alcohols to Alkyl Halides
35:43
Reagents that Provide LG and Nu: in One 'Pot'
35:44
General Mechanisms
37:44
Example 1: General Mechanisms
37:45
Example 2: General Mechanisms
39:25
Example
41:04
Transformation of Alcohols
41:05
V. Ethers, Thiols, Thioethers, & Ketones
Ethers

1h 34m 45s

Intro
0:00
Ethers
0:11
Overview of Ethers
0:12
Boiling Points
1:37
Ethers
4:34
Water Solubility (Grams per 100mL H₂O)
4:35
Synthesis of Ethers
7:53
Williamson Ether Synthesis
7:54
Example: Synthesis of Ethers
9:23
Synthesis of Ethers
10:27
Example: Synthesis of Ethers
10:28
Intramolecular SN2
13:04
Planning an Ether Synthesis
14:45
Example 1: Planning an Ether Synthesis
14:46
Planning an Ether Synthesis
16:16
Example 2: Planning an Ether Synthesis
16:17
Planning an Ether Synthesis
22:04
Example 3: Synthesize Dipropyl Ether
22:05
Planning an Ether Synthesis
26:01
Example 4: Transform
26:02
Synthesis of Epoxides
30:05
Synthesis of Epoxides Via Williamson Ether Synthesis
30:06
Synthesis of Epoxides Via Oxidation
32:42
Reaction of Ethers
33:35
Reaction of Ethers
33:36
Reactions of Ethers with HBr or HI
34:44
Reactions of Ethers with HBr or HI
34:45
Mechanism
35:25
Epoxide Ring-Opening Reaction
39:25
Epoxide Ring-Opening Reaction
39:26
Example: Epoxide Ring-Opening Reaction
42:42
Acid-Catalyzed Epoxide Ring Opening
44:16
Acid-Catalyzed Epoxide Ring Opening Mechanism
44:17
Acid-Catalyzed Epoxide Ring Opening
50:13
Acid-Catalyzed Epoxide Ring Opening Mechanism
50:14
Catalyst Needed for Ring Opening
53:34
Catalyst Needed for Ring Opening
53:35
Stereochemistry of Epoxide Ring Opening
55:56
Stereochemistry: SN2 Mechanism
55:57
Acid or Base Mechanism?
58:30
Example
1:01:03
Transformation
1:01:04
Regiochemistry of Epoxide Ring Openings
1:05:29
Regiochemistry of Epoxide Ring Openings in Base
1:05:30
Regiochemistry of Epoxide Ring Openings in Acid
1:07:34
Example
1:10:26
Example 1: Epoxide Ring Openings in Base
1:10:27
Example 2: Epoxide Ring Openings in Acid
1:12:50
Reactions of Epoxides with Grignard and Hydride
1:15:35
Reactions of Epoxides with Grignard and Hydride
1:15:36
Example
1:21:47
Example: Ethers
1:21:50
Example
1:27:01
Example: Synthesize
1:27:02
Thiols and Thioethers

16m 50s

Intro
0:00
Thiols and Thioethers
0:10
Physical Properties
0:11
Reactions Can Be Oxidized
2:16
Acidity of Thiols
3:11
Thiols Are More Acidic Than Alcohols
3:12
Synthesis of Thioethers
6:44
Synthesis of Thioethers
6:45
Example
8:43
Example: Synthesize the Following Target Molecule
8:44
Example
14:18
Example: Predict
14:19
Ketones

2h 18m 12s

Intro
0:00
Aldehydes & Ketones
0:11
The Carbonyl: Resonance & Inductive
0:12
Reactivity
0:50
The Carbonyl
2:35
The Carbonyl
2:36
Carbonyl FG's
4:10
Preparation/Synthesis of Aldehydes & Ketones
6:18
Oxidation of Alcohols
6:19
Ozonolysis of Alkenes
7:16
Hydration of Alkynes
8:01
Reaction with Hydride Nu:
9:00
Reaction with Hydride Nu:
9:01
Reaction with Carbon Nu:
11:29
Carbanions: Acetylide
11:30
Carbanions: Cyanide
14:23
Reaction with Carbon Nu:
15:32
Organometallic Reagents (RMgX, Rli)
15:33
Retrosynthesis of Alcohols
17:04
Retrosynthesis of Alcohols
17:05
Example
19:30
Example: Transform
19:31
Example
22:57
Example: Transform
22:58
Example
28:19
Example: Transform
28:20
Example
33:36
Example: Transform
33:37
Wittig Reaction
37:39
Wittig Reaction: A Resonance-Stabilized Carbanion (Nu:)
37:40
Wittig Reaction: Mechanism
39:51
Preparation of Wittig Reagent
41:58
Two Steps From RX
41:59
Example: Predict
45:02
Wittig Retrosynthesis
46:19
Wittig Retrosynthesis
46:20
Synthesis
48:09
Reaction with Oxygen Nu:
51:21
Addition of H₂O
51:22
Exception: Formaldehyde is 99% Hydrate in H₂O Solution
54:10
Exception: Hydrate is Favored if Partial Positive Near Carbonyl
55:26
Reaction with Oxygen Nu:
57:45
Addition of ROH
57:46
TsOH: Tosic Acid
58:28
Addition of ROH Cont.
59:09
Example
1:01:43
Predict
1:01:44
Mechanism
1:03:08
Mechanism for Acetal Formation
1:04:10
Mechanism for Acetal Formation
1:04:11
What is a CTI?
1:15:04
Tetrahedral Intermediate
1:15:05
Charged Tetrahedral Intermediate
1:15:45
CTI: Acid-cat
1:16:10
CTI: Base-cat
1:17:01
Acetals & Cyclic Acetals
1:17:49
Overall
1:17:50
Cyclic Acetals
1:18:46
Hydrolysis of Acetals: Regenerates Carbonyl
1:20:01
Hydrolysis of Acetals: Regenerates Carbonyl
1:20:02
Mechanism
1:22:08
Reaction with Nitrogen Nu:
1:30:11
Reaction with Nitrogen Nu:
1:30:12
Example
1:32:18
Mechanism of Imine Formation
1:33:24
Mechanism of Imine Formation
1:33:25
Oxidation of Aldehydes
1:38:12
Oxidation of Aldehydes 1
1:38:13
Oxidation of Aldehydes 2
1:39:52
Oxidation of Aldehydes 3
1:40:10
Reductions of Ketones and Aldehydes
1:40:54
Reductions of Ketones and Aldehydes
1:40:55
Hydride/ Workup
1:41:22
Raney Nickel
1:42:07
Reductions of Ketones and Aldehydes
1:43:24
Clemmensen Reduction & Wolff-Kishner Reduction
1:43:40
Acetals as Protective Groups
1:46:50
Acetals as Protective Groups
1:46:51
Example
1:50:39
Example: Consider the Following Synthesis
1:50:40
Protective Groups
1:54:47
Protective Groups
1:54:48
Example
1:59:02
Example: Transform
1:59:03
Example: Another Route
2:04:54
Example: Transform
2:08:49
Example
2:08:50
Transform
2:08:51
Example
2:11:05
Transform
2:11:06
Example
2:13:45
Transform
2:13:46
Example
2:15:43
Provide the Missing Starting Material
2:15:44
VI. Organic Transformation Practice
Transformation Practice Problems

38m 58s

Intro
0:00
Practice Problems
0:33
Practice Problem 1: Transform
0:34
Practice Problem 2: Transform
3:57
Practice Problems
7:49
Practice Problem 3: Transform
7:50
Practice Problems
15:32
Practice Problem 4: Transform
15:34
Practice Problem 5: Transform
20:15
Practice Problems
24:08
Practice Problem 6: Transform
24:09
Practice Problem 7: Transform
29:27
Practice Problems
33:08
Practice Problem 8: Transform
33:09
Practice Problem 9: Transform
35:23
VII. Carboxylic Acids
Carboxylic Acids

1h 17m 51s

Intro
0:00
Review Reactions of Ketone/Aldehyde
0:06
Carbonyl Reactivity
0:07
Nu: = Hydride (Reduction)
1:37
Nu: = Grignard
2:08
Review Reactions of Ketone/Aldehyde
2:53
Nu: = Alcohol
2:54
Nu: = Amine
3:46
Carboxylic Acids and Their Derivatives
4:37
Carboxylic Acids and Their Derivatives
4:38
Ketone vs. Ester Reactivity
6:33
Ketone Reactivity
6:34
Ester Reactivity
6:55
Carboxylic Acids and Their Derivatives
7:30
Acid Halide, Anhydride, Ester, Amide, and Nitrile
7:43
General Reactions of Acarboxylic Acid Derivatives
9:22
General Reactions of Acarboxylic Acid Derivatives
9:23
Physical Properties of Carboxylic Acids
12:16
Acetic Acid
12:17
Carboxylic Acids
15:46
Aciditiy of Carboxylic Acids, RCO₂H
17:45
Alcohol
17:46
Carboxylic Acid
19:21
Aciditiy of Carboxylic Acids, RCO₂H
21:31
Aciditiy of Carboxylic Acids, RCO₂H
21:32
Aciditiy of Carboxylic Acids, RCO₂H
24:48
Example: Which is the Stronger Acid?
24:49
Aciditiy of Carboxylic Acids, RCO₂H
30:06
Inductive Effects Decrease with Distance
30:07
Preparation of Carboxylic Acids, RCO₂H
31:55
A) By Oxidation
31:56
Preparation of Carboxylic Acids, RCO₂H
34:37
Oxidation of Alkenes/Alkynes - Ozonolysis
34:38
Preparation of Carboxylic Acids, RCO₂H
36:17
B) Preparation of RCO₂H from Organometallic Reagents
36:18
Preparation of Carboxylic Acids, RCO₂H
38:02
Example: Preparation of Carboxylic Acids
38:03
Preparation of Carboxylic Acids, RCO₂H
40:38
C) Preparation of RCO₂H by Hydrolysis of Carboxylic Acid Derivatives
40:39
Hydrolysis Mechanism
42:19
Hydrolysis Mechanism
42:20
Mechanism: Acyl Substitution (Addition/Elimination)
43:05
Hydrolysis Mechanism
47:27
Substitution Reaction
47:28
RO is Bad LG for SN1/SN2
47:39
RO is okay LG for Collapse of CTI
48:31
Hydrolysis Mechanism
50:07
Base-promoted Ester Hydrolysis (Saponification)
50:08
Applications of Carboxylic Acid Derivatives:
53:10
Saponification Reaction
53:11
Ester Hydrolysis
57:15
Acid-Catalyzed Mechanism
57:16
Ester Hydrolysis Requires Acide or Base
1:03:06
Ester Hydrolysis Requires Acide or Base
1:03:07
Nitrile Hydrolysis
1:05:22
Nitrile Hydrolysis
1:05:23
Nitrile Hydrolysis Mechanism
1:06:53
Nitrile Hydrolysis Mechanism
1:06:54
Use of Nitriles in Synthesis
1:12:39
Example: Nitirles in Synthesis
1:12:40
Carboxylic Acid Derivatives

1h 21m 4s

Intro
0:00
Carboxylic Acid Derivatives
0:05
Carboxylic Acid Derivatives
0:06
General Structure
1:00
Preparation of Carboxylic Acid Derivatives
1:19
Which Carbonyl is the Better E+?
1:20
Inductive Effects
1:54
Resonance
3:23
Preparation of Carboxylic Acid Derivatives
6:52
Which is Better E+, Ester or Acid Chloride?
6:53
Inductive Effects
7:02
Resonance
7:20
Preparation of Carboxylic Acid Derivatives
10:45
Which is Better E+, Carboxylic Acid or Anhydride?
10:46
Inductive Effects & Resonance
11:00
Overall: Order of Electrophilicity and Leaving Group
14:49
Order of Electrophilicity and Leaving Group
14:50
Example: Acid Chloride
16:26
Example: Carboxylate
19:17
Carboxylic Acid Derivative Interconversion
20:53
Carboxylic Acid Derivative Interconversion
20:54
Preparation of Acid Halides
24:31
Preparation of Acid Halides
24:32
Preparation of Anhydrides
25:45
A) Dehydration of Acids (For Symmetrical Anhydride)
25:46
Preparation of Anhydrides
27:29
Example: Dehydration of Acids
27:30
Preparation of Anhydrides
29:16
B) From an Acid Chloride (To Make Mixed Anhydride)
29:17
Mechanism
30:03
Preparation of Esters
31:53
A) From Acid Chloride or Anhydride
31:54
Preparation of Esters
33:48
B) From Carboxylic Acids (Fischer Esterification)
33:49
Mechanism
36:55
Preparations of Esters
41:38
Example: Predict the Product
41:39
Preparation of Esters
43:17
C) Transesterification
43:18
Mechanism
45:17
Preparation of Esters
47:58
D) SN2 with Carboxylate
47:59
Mechanism: Diazomethane
49:28
Preparation of Esters
51:01
Example: Transform
51:02
Preparation of Amides
52:27
A) From an Acid Cl or Anhydride
52:28
Preparations of Amides
54:47
B) Partial Hydrolysis of Nitriles
54:48
Preparation of Amides
56:11
Preparation of Amides: Find Alternate Path
56:12
Preparation of Amides
59:04
C) Can't be Easily Prepared from RCO₂H Directly
59:05
Reactions of Carboxylic Acid Derivatives with Nucleophiles
1:01:41
A) Hydride Nu: Review
1:01:42
A) Hydride Nu: Sodium Borohydride + Ester
1:02:43
Reactions of Carboxylic Acid Derivatives with Nucleophiles
1:03:57
Lithium Aluminum Hydride (LAH)
1:03:58
Mechanism
1:04:29
Summary of Hydride Reductions
1:07:09
Summary of Hydride Reductions 1
1:07:10
Summary of Hydride Reductions 2
1:07:36
Hydride Reduction of Amides
1:08:12
Hydride Reduction of Amides Mechanism
1:08:13
Reaction of Carboxylic Acid Derivatives with Organometallics
1:12:04
Review 1
1:12:05
Review 2
1:12:50
Reaction of Carboxylic Acid Derivatives with Organometallics
1:14:22
Example: Lactone
1:14:23
Special Hydride Nu: Reagents
1:16:34
Diisobutylaluminum Hydride
1:16:35
Example
1:17:25
Other Special Hydride
1:18:41
Addition of Organocuprates to Acid Chlorides
1:19:07
Addition of Organocuprates to Acid Chlorides
1:19:08
VIII. Enols & Enolates
Enols and Enolates, Part 1

1h 26m 22s

Intro
0:00
Enols and Enolates
0:09
The Carbonyl
0:10
Keto-Enol Tautomerization
1:17
Keto-Enol Tautomerization Mechanism
2:28
Tautomerization Mechanism (2 Steps)
2:29
Keto-Enol Tautomerization Mechanism
5:15
Reverse Reaction
5:16
Mechanism
6:07
Formation of Enolates
7:27
Why is a Ketone's α H's Acidic?
7:28
Formation of Other Carbanions
10:05
Alkyne
10:06
Alkane and Alkene
10:53
Formation of an Enolate: Choice of Base
11:27
Example: Choice of Base
11:28
Formation of an Enolate: Choice of Base
13:56
Deprotonate, Stronger Base, and Lithium Diisopropyl Amide (LDA)
13:57
Formation of an Enolate: Choice of Base
15:48
Weaker Base & 'Active' Methylenes
15:49
Why Use NaOEt instead of NaOH?
19:01
Other Acidic 'α' Protons
20:30
Other Acidic 'α' Protons
20:31
Why is an Ester Less Acidic than a Ketone?
24:10
Other Acidic 'α' Protons
25:19
Other Acidic 'α' Protons Continue
25:20
How are Enolates Used
25:54
Enolates
25:55
Possible Electrophiles
26:21
Alkylation of Enolates
27:56
Alkylation of Enolates
27:57
Resonance Form
30:03
α-Halogenation
32:17
α-Halogenation
32:18
Iodoform Test for Methyl Ketones
33:47
α-Halogenation
35:55
Acid-Catalyzed
35:57
Mechanism: 1st Make Enol (2 Steps)
36:14
Whate Other Eloctrophiles ?
39:17
Aldol Condensation
39:38
Aldol Condensation
39:39
Aldol Mechanism
41:26
Aldol Mechanism: In Base, Deprotonate First
41:27
Aldol Mechanism
45:28
Mechanism for Loss of H₂O
45:29
Collapse of CTI and β-elimination Mechanism
47:51
Loss of H₂0 is not E2!
48:39
Aldol Summary
49:53
Aldol Summary
49:54
Base-Catalyzed Mechanism
52:34
Acid-Catalyzed Mechansim
53:01
Acid-Catalyzed Aldol Mechanism
54:01
First Step: Make Enol
54:02
Acid-Catalyzed Aldol Mechanism
56:54
Loss of H₂0 (β elimination)
56:55
Crossed/Mixed Aldol
1:00:55
Crossed/Mixed Aldol & Compound with α H's
1:00:56
Ketone vs. Aldehyde
1:02:30
Crossed/Mixed Aldol & Compound with α H's Continue
1:03:10
Crossed/Mixed Aldol
1:05:21
Mixed Aldol: control Using LDA
1:05:22
Crossed/Mixed Aldol Retrosynthesis
1:08:53
Example: Predic Aldol Starting Material (Aldol Retrosyntheiss)
1:08:54
Claisen Condensation
1:12:54
Claisen Condensation (Aldol on Esters)
1:12:55
Claisen Condensation
1:19:52
Example 1: Claisen Condensation
1:19:53
Claisen Condensation
1:22:48
Example 2: Claisen Condensation
1:22:49
Enols and Enolates, Part 2

50m 57s

Intro
0:00
Conjugate Additions
0:06
α, β-unsaturated Carbonyls
0:07
Conjugate Additions
1:50
'1,2-addition'
1:51
'1,-4-addition' or 'Conjugate Addition'
2:24
Conjugate Additions
4:53
Why can a Nu: Add to this Alkene?
4:54
Typical Alkene
5:09
α, β-unsaturated Alkene
5:39
Electrophilic Alkenes: Michael Acceptors
6:35
Other 'Electrophilic' Alkenes (Called 'Michael Acceptors)
6:36
1,4-Addition of Cuprates (R2CuLi)
8:29
1,4-Addition of Cuprates (R2CuLi)
8:30
1,4-Addition of Cuprates (R2CuLi)
11:23
Use Cuprates in Synthesis
11:24
Preparation of Cuprates
12:25
Prepare Organocuprate From Organolithium
12:26
Cuprates Also Do SN2 with RX E+ (Not True for RMgX, RLi)
13:06
1,4-Addition of Enolates: Michael Reaction
13:50
1,4-Addition of Enolates: Michael Reaction
13:51
Mechanism
15:57
1,4-Addition of Enolates: Michael Reaction
18:47
Example: 1,4-Addition of Enolates
18:48
1,4-Addition of Enolates: Michael Reaction
21:02
Michael Reaction, Followed by Intramolecular Aldol
21:03
Mechanism of the Robinson Annulation
24:26
Mechanism of the Robinson Annulation
24:27
Enols and Enolates: Advanced Synthesis Topics
31:10
Stablized Enolates and the Decarboxylation Reaction
31:11
Mechanism: A Pericyclic Reaction
32:08
Enols and Enolates: Advanced Synthesis Topics
33:32
Example: Advance Synthesis
33:33
Enols and Enolates: Advanced Synthesis Topics
36:10
Common Reagents: Diethyl Malonate
36:11
Common Reagents: Ethyl Acetoacetate
37:27
Enols and Enolates: Advanced Synthesis Topics
38:06
Example: Transform
38:07
Advanced Synthesis Topics: Enamines
41:52
Enamines
41:53
Advanced Synthesis Topics: Enamines
43:06
Reaction with Ketone/Aldehyde
43:07
Example
44:08
Advanced Synthesis Topics: Enamines
45:31
Example: Use Enamines as Nu: (Like Enolate)
45:32
Advanced Synthesis Topics: Enamines
47:56
Example
47:58
IX. Aromatic Compounds
Aromatic Compounds: Structure

1h 59s

Intro
0:00
Aromatic Compounds
0:05
Benzene
0:06
3D Sketch
1:33
Features of Benzene
4:41
Features of Benzene
4:42
Aromatic Stability
6:41
Resonance Stabilization of Benzene
6:42
Cyclohexatriene
7:24
Benzene (Actual, Experimental)
8:11
Aromatic Stability
9:03
Energy Graph
9:04
Aromaticity Requirements
9:55
1) Cyclic and Planar
9:56
2) Contiguous p Orbitals
10:49
3) Satisfy Huckel's Rule
11:20
Example: Benzene
12:32
Common Aromatic Compounds
13:28
Example: Pyridine
13:29
Common Aromatic Compounds
16:25
Example: Furan
16:26
Common Aromatic Compounds
19:42
Example: Thiophene
19:43
Example: Pyrrole
20:18
Common Aromatic Compounds
21:09
Cyclopentadienyl Anion
21:10
Cycloheptatrienyl Cation
23:48
Naphthalene
26:04
Determining Aromaticity
27:28
Example: Which of the Following are Aromatic?
27:29
Molecular Orbital (MO) Theory
32:26
What's So Special About '4n + 2' Electrons?
32:27
π bond & Overlapping p Orbitals
32:53
Molecular Orbital (MO) Diagrams
36:56
MO Diagram: Benzene
36:58
Drawing MO Diagrams
44:26
Example: 3-Membered Ring
44:27
Example: 4-Membered Ring
46:04
Drawing MO Diagrams
47:51
Example: 5-Membered Ring
47:52
Example: 8-Membered Ring
49:32
Aromaticity and Reactivity
51:03
Example: Which is More Acidic?
51:04
Aromaticity and Reactivity
56:03
Example: Which has More Basic Nitrogen, Pyrrole or Pyridine?
56:04
Aromatic Compounds: Reactions, Part 1

1h 24m 4s

Intro
0:00
Reactions of Benzene
0:07
N/R as Alkenes
0:08
Substitution Reactions
0:50
Electrophilic Aromatic Substitution
1:24
Electrophilic Aromatic Substitution
1:25
Mechanism Step 1: Addition of Electrophile
2:08
Mechanism Step 2: Loss of H+
4:14
Electrophilic Aromatic Substitution on Substituted Benzenes
5:21
Electron Donating Group
5:22
Electron Withdrawing Group
8:02
Halogen
9:23
Effects of Electron-Donating Groups (EDG)
10:23
Effects of Electron-Donating Groups (EDG)
10:24
What Effect Does EDG (OH) Have?
11:40
Reactivity
13:03
Regioselectivity
14:07
Regioselectivity: EDG is o/p Director
14:57
Prove It! Add E+ and Look at Possible Intermediates
14:58
Is OH Good or Bad?
17:38
Effects of Electron-Withdrawing Groups (EWG)
20:20
What Effect Does EWG Have?
20:21
Reactivity
21:28
Regioselectivity
22:24
Regioselectivity: EWG is a Meta Director
23:23
Prove It! Add E+ and Look at Competing Intermediates
23:24
Carbocation: Good or Bad?
26:01
Effects of Halogens on EAS
28:33
Inductive Withdrawal of e- Density vs. Resonance Donation
28:34
Summary of Substituent Effects on EAS
32:33
Electron Donating Group
32:34
Electron Withdrawing Group
33:37
Directing Power of Substituents
34:35
Directing Power of Substituents
34:36
Example
36:41
Electrophiles for Electrophilic Aromatic Substitution
38:43
Reaction: Halogenation
38:44
Electrophiles for Electrophilic Aromatic Substitution
40:27
Reaction: Nitration
40:28
Electrophiles for Electrophilic Aromatic Substitution
41:45
Reaction: Sulfonation
41:46
Electrophiles for Electrophilic Aromatic Substitution
43:19
Reaction: Friedel-Crafts Alkylation
43:20
Electrophiles for Electrophilic Aromatic Substitution
45:43
Reaction: Friedel-Crafts Acylation
45:44
Electrophilic Aromatic Substitution: Nitration
46:52
Electrophilic Aromatic Substitution: Nitration
46:53
Mechanism
48:56
Nitration of Aniline
52:40
Nitration of Aniline Part 1
52:41
Nitration of Aniline Part 2: Why?
54:12
Nitration of Aniline
56:10
Workaround: Protect Amino Group as an Amide
56:11
Electrophilic Aromatic Substitution: Sulfonation
58:16
Electrophilic Aromatic Substitution: Sulfonation
58:17
Example: Transform
59:25
Electrophilic Aromatic Substitution: Friedel-Crafts Alkylation
1:02:24
Electrophilic Aromatic Substitution: Friedel-Crafts Alkylation
1:02:25
Example & Mechanism
1:03:37
Friedel-Crafts Alkylation Drawbacks
1:05:48
A) Can Over-React (Dialkylation)
1:05:49
Friedel-Crafts Alkylation Drawbacks
1:08:21
B) Carbocation Can Rearrange
1:08:22
Mechanism
1:09:33
Friedel-Crafts Alkylation Drawbacks
1:13:35
Want n-Propyl? Use Friedel-Crafts Acylation
1:13:36
Reducing Agents
1:16:45
Synthesis with Electrophilic Aromatic Substitution
1:18:45
Example: Transform
1:18:46
Synthesis with Electrophilic Aromatic Substitution
1:20:59
Example: Transform
1:21:00
Aromatic Compounds: Reactions, Part 2

59m 10s

Intro
0:00
Reagents for Electrophilic Aromatic Substitution
0:07
Reagents for Electrophilic Aromatic Substitution
0:08
Preparation of Diazonium Salt
2:12
Preparation of Diazonium Salt
2:13
Reagents for Sandmeyer Reactions
4:14
Reagents for Sandmeyer Reactions
4:15
Apply Diazonium Salt in Synthesis
6:20
Example: Transform
6:21
Apply Diazonium Salt in Synthesis
9:14
Example: Synthesize Following Target Molecule from Benzene or Toluene
9:15
Apply Diazonium Salt in Synthesis
14:56
Example: Transform
14:57
Reactions of Aromatic Substituents
21:56
A) Reduction Reactions
21:57
Reactions of Aromatic Substituents
23:24
B) Oxidations of Arenes
23:25
Benzylic [ox] Even Breaks C-C Bonds!
25:05
Benzylic Carbon Can't Be Quaternary
25:55
Reactions of Aromatic Substituents
26:21
Example
26:22
Review of Benzoic Acid Synthesis
27:34
Via Hydrolysis
27:35
Via Grignard
28:20
Reactions of Aromatic Substituents
29:15
C) Benzylic Halogenation
29:16
Radical Stabilities
31:55
N-bromosuccinimide (NBS)
32:23
Reactions of Aromatic Substituents
33:08
D) Benzylic Substitutions
33:09
Reactions of Aromatic Side Chains
37:08
Example: Transform
37:09
Nucleophilic Aromatic Substitution
43:13
Nucleophilic Aromatic Substitution
43:14
Nucleophilic Aromatic Substitution
47:08
Example
47:09
Mechanism
48:00
Nucleophilic Aromatic Substitution
50:43
Example
50:44
Nucleophilic Substitution: Benzyne Mechanism
52:46
Nucleophilic Substitution: Benzyne Mechanism
52:47
Nucleophilic Substitution: Benzyne Mechanism
57:31
Example: Predict Product
57:32
X. Dienes & Amines
Conjugated Dienes

1h 9m 12s

Intro
0:00
Conjugated Dienes
0:08
Conjugated π Bonds
0:09
Diene Stability
2:00
Diene Stability: Cumulated
2:01
Diene Stability: Isolated
2:37
Diene Stability: Conjugated
2:51
Heat of Hydrogenation
3:00
Allylic Carbocations and Radicals
5:15
Allylic Carbocations and Radicals
5:16
Electrophilic Additions to Dienes
7:00
Alkenes
7:01
Unsaturated Ketone
7:47
Electrophilic Additions to Dienes
8:28
Conjugated Dienes
8:29
Electrophilic Additions to Dienes
9:46
Mechanism (2-Steps): Alkene
9:47
Electrophilic Additions to Dienes
11:40
Mechanism (2-Steps): Diene
11:41
1,2 'Kinetic' Product
13:08
1,4 'Thermodynamic' Product
14:47
E vs. POR Diagram
15:50
E vs. POR Diagram
15:51
Kinetic vs. Thermodynamic Control
21:56
Kinetic vs. Thermodynamic Control
21:57
How? Reaction is Reversible!
23:51
1,2 (Less Stable product)
23:52
1,4 (More Stable Product)
25:16
Diels Alder Reaction
26:34
Diels Alder Reaction
26:35
Dienophiles (E+)
29:23
Dienophiles (E+)
29:24
Alkyne Diels-Alder Example
30:48
Example: Alkyne Diels-Alder
30:49
Diels-Alder Reaction: Dienes (Nu:)
32:22
Diels-Alder ReactionL Dienes (Nu:)
32:23
Diels-Alder Reaction: Dienes
33:51
Dienes Must Have 's-cis' Conformation
33:52
Example
35:25
Diels-Alder Reaction with Cyclic Dienes
36:08
Cyclic Dienes are Great for Diels-Alder Reaction
36:09
Cyclopentadiene
37:10
Diels-Alder Reaction: Bicyclic Products
40:50
Endo vs. Exo Terminology: Norbornane & Bicyclo Heptane
40:51
Example: Bicyclo Heptane
42:29
Diels-Alder Reaction with Cyclic Dienes
44:15
Example
44:16
Stereochemistry of the Diels-Alder Reaction
47:39
Stereochemistry of the Diels-Alder Reaction
47:40
Example
48:08
Stereochemistry of the Diels-Alder Reaction
50:21
Example
50:22
Regiochemistry of the Diels-Alder Reaction
52:42
Rule: 1,2-Product Preferred Over 1,3-Product
52:43
Regiochemistry of the Diels-Alder Reaction
54:18
Rule: 1,4-Product Preferred Over 1,3-Product
54:19
Regiochemistry of the Diels-Alder Reaction
55:02
Why 1,2-Product or 1,4-Product Favored?
55:03
Example
56:11
Diels-Alder Reaction
58:06
Example: Predict
58:07
Diels-Alder Reaction
1:01:27
Explain Why No Diels-Alder Reaction Takes Place in This Case
1:01:28
Diels-Alder Reaction
1:03:09
Example: Predict
1:03:10
Diels-Alder Reaction: Synthesis Problem
1:05:39
Diels-Alder Reaction: Synthesis Problem
1:05:40
Pericyclic Reactions and Molecular Orbital (MO) Theory

1h 21m 31s

Intro
0:00
Pericyclic Reactions
0:05
Pericyclic Reactions
0:06
Electrocyclic Reactions
1:19
Electrocyclic Reactions
1:20
Electrocyclic Reactions
3:13
Stereoselectivity
3:14
Electrocyclic Reactions
8:10
Example: Predict
8:11
Sigmatropic Rearrangements
12:29
Sigmatropic Rearrangements
12:30
Cope Rearrangement
14:44
Sigmatropic Rearrangements
16:44
Claisen Rearrangement 1
16:45
Claisen Rearrangement 2
17:46
Cycloaddition Reactions
19:22
Diels-Alder
19:23
1,3-Dipolar Cycloaddition
20:32
Cycloaddition Reactions: Stereochemistry
21:58
Cycloaddition Reactions: Stereochemistry
21:59
Cycloaddition Reactions: Heat or Light?
26:00
4+2 Cycloadditions
26:01
2+2 Cycloadditions
27:23
Molecular Orbital (MO) Theory of Chemical Reactions
29:26
Example 1: Molecular Orbital Theory of Bonding
29:27
Molecular Orbital (MO) Theory of Chemical Reactions
31:59
Example 2: Molecular Orbital Theory of Bonding
32:00
Molecular Orbital (MO) Theory of Chemical Reactions
33:33
MO Theory of Aromaticity, Huckel's Rule
33:34
Molecular Orbital (MO) Theory of Chemical Reactions
36:43
Review: Molecular Orbital Theory of Conjugated Systems
36:44
Molecular Orbital (MO) Theory of Chemical Reactions
44:56
Review: Molecular Orbital Theory of Conjugated Systems
44:57
Molecular Orbital (MO) Theory of Chemical Reactions
46:54
Review: Molecular Orbital Theory of Conjugated Systems
46:55
Molecular Orbital (MO) Theory of Chemical Reactions
48:36
Frontier Molecular Orbitals are Involved in Reactions
48:37
Examples
50:20
MO Theory of Pericyclic Reactions: The Woodward-Hoffmann Rules
51:51
Heat-promoted Pericyclic Reactions and Light-promoted Pericyclic Reactions
51:52
MO Theory of Pericyclic Reactions: The Woodward-Hoffmann Rules
53:42
Why is a [4+2] Cycloaddition Thermally Allowed While the [2+2] is Not?
53:43
MO Theory of Pericyclic Reactions: The Woodward-Hoffmann Rules
56:51
Why is a [2+2] Cycloaddition Photochemically Allowed?
56:52
Pericyclic Reaction Example I
59:16
Pericyclic Reaction Example I
59:17
Pericyclic Reaction Example II
1:07:40
Pericyclic Reaction Example II
1:07:41
Pericyclic Reaction Example III: Vitamin D - The Sunshine Vitamin
1:14:22
Pericyclic Reaction Example III: Vitamin D - The Sunshine Vitamin
1:14:23
Amines

34m 58s

Intro
0:00
Amines: Properties and Reactivity
0:04
Compare Amines to Alcohols
0:05
Amines: Lower Boiling Point than ROH
0:55
1) RNH₂ Has Lower Boiling Point than ROH
0:56
Amines: Better Nu: Than ROH
2:22
2) RNH₂ is a Better Nucleophile than ROH Example 1
2:23
RNH₂ is a Better Nucleophile than ROH Example 2
3:08
Amines: Better Nu: than ROH
3:47
Example
3:48
Amines are Good Bases
5:41
3) RNH₂ is a Good Base
5:42
Amines are Good Bases
7:06
Example 1
7:07
Example 2: Amino Acid
8:27
Alkyl vs. Aryl Amines
9:56
Example: Which is Strongest Base?
9:57
Alkyl vs. Aryl Amines
14:55
Verify by Comparing Conjugate Acids
14:56
Reaction of Amines
17:42
Reaction with Ketone/Aldehyde: 1° Amine (RNH₂)
17:43
Reaction of Amines
18:48
Reaction with Ketone/Aldehyde: 2° Amine (R2NH)
18:49
Use of Enamine: Synthetic Equivalent of Enolate
20:08
Use of Enamine: Synthetic Equivalent of Enolate
20:09
Reaction of Amines
24:10
Hofmann Elimination
24:11
Hofmann Elimination
26:16
Kinetic Product
26:17
Structure Analysis Using Hofmann Elimination
28:22
Structure Analysis Using Hofmann Elimination
28:23
Biological Activity of Amines
30:30
Adrenaline
31:07
Mescaline (Peyote Alkaloid)
31:22
Amino Acids, Amide, and Protein
32:14
Biological Activity of Amines
32:50
Morphine (Opium Alkaloid)
32:51
Epibatidine (Poison Dart Frog)
33:28
Nicotine
33:48
Choline (Nerve Impulse)
34:03
XI. Biomolecules & Polymers
Biomolecules

1h 53m 20s

Intro
0:00
Carbohydrates
1:11
D-glucose Overview
1:12
D-glucose: Cyclic Form (6-membered ring)
4:31
Cyclic Forms of Glucose: 6-membered Ring
8:24
α-D-glucopyranose & β-D-glucopyranose
8:25
Formation of a 5-Membered Ring
11:05
D-glucose: Formation of a 5-Membered Ring
11:06
Cyclic Forms of Glucose: 5-membered Ring
12:37
α-D-glucofuranose & β-D-glucofuranose
12:38
Carbohydrate Mechanism
14:03
Carbohydrate Mechanism
14:04
Reactions of Glucose: Acetal Formation
21:35
Acetal Formation: Methyl-α-D-glucoside
21:36
Hemiacetal to Acetal: Overview
24:58
Mechanism for Formation of Glycosidic Bond
25:51
Hemiacetal to Acetal: Mechanism
25:52
Formation of Disaccharides
29:34
Formation of Disaccharides
29:35
Some Polysaccharides: Starch
31:33
Amylose & Amylopectin
31:34
Starch: α-1,4-glycosidic Bonds
32:22
Properties of Starch Molecule
33:21
Some Polysaccharides: Cellulose
33:59
Cellulose: β-1,4-glycosidic bonds
34:00
Properties of Cellulose
34:59
Other Sugar-Containing Biomolecules
35:50
Ribonucleoside (RNA)
35:51
Deoxyribonucleoside (DMA)
36:59
Amino Acids & Proteins
37:32
α-amino Acids: Structure & Stereochemistry
37:33
Making a Protein (Condensation)
42:46
Making a Protein (Condensation)
42:47
Peptide Bond is Planar (Amide Resonance)
44:55
Peptide Bond is Planar (Amide Resonance)
44:56
Protein Functions
47:49
Muscle, Skin, Bones, Hair Nails
47:50
Enzymes
49:10
Antibodies
49:44
Hormones, Hemoglobin
49:58
Gene Regulation
50:20
Various Amino Acid Side Chains
50:51
Nonpolar
50:52
Polar
51:15
Acidic
51:24
Basic
51:55
Amino Acid Table
52:22
Amino Acid Table
52:23
Isoelectric Point (pI)
53:43
Isoelectric Point (pI) of Glycine
53:44
Isoelectric Point (pI) of Glycine: pH 11
56:42
Isoelectric Point (pI) of Glycine: pH 1
57:20
Isoelectric Point (pI), cont.
58:05
Asparatic Acid
58:06
Histidine
1:00:28
Isoelectric Point (pI), cont.
1:02:54
Example: What is the Net Charge of This Tetrapeptide at pH 6.0?
1:02:55
Nucleic Acids: Ribonucleosides
1:10:32
Nucleic Acids: Ribonucleosides
1:10:33
Nucleic Acids: Ribonucleotides
1:11:48
Ribonucleotides: 5' Phosphorylated Ribonucleosides
1:11:49
Ribonucleic Acid (RNA) Structure
1:12:35
Ribonucleic Acid (RNA) Structure
1:12:36
Nucleic Acids: Deoxyribonucleosides
1:14:08
Nucleic Acids: Deoxyribonucleosides
1:14:09
Deoxythymidine (T)
1:14:36
Nucleic Acids: Base-Pairing
1:15:17
Nucleic Acids: Base-Pairing
1:15:18
Double-Stranded Structure of DNA
1:18:16
Double-Stranded Structure of DNA
1:18:17
Model of DNA
1:19:40
Model of DNA
1:19:41
Space-Filling Model of DNA
1:20:46
Space-Filling Model of DNA
1:20:47
Function of RNA and DNA
1:23:06
DNA & Transcription
1:23:07
RNA & Translation
1:24:22
Genetic Code
1:25:09
Genetic Code
1:25:10
Lipids/Fats/Triglycerides
1:27:10
Structure of Glycerol
1:27:43
Saturated & Unsaturated Fatty Acids
1:27:51
Triglyceride
1:28:43
Unsaturated Fats: Lower Melting Points (Liquids/Oils)
1:29:15
Saturated Fat
1:29:16
Unsaturated Fat
1:30:10
Partial Hydrogenation
1:32:05
Saponification of Fats
1:35:11
Saponification of Fats
1:35:12
History of Soap
1:36:50
Carboxylate Salts form Micelles in Water
1:41:02
Carboxylate Salts form Micelles in Water
1:41:03
Cleaning Power of Micelles
1:42:21
Cleaning Power of Micelles
1:42:22
3-D Image of a Micelle
1:42:58
3-D Image of a Micelle
1:42:59
Synthesis of Biodiesel
1:44:04
Synthesis of Biodiesel
1:44:05
Phosphoglycerides
1:47:54
Phosphoglycerides
1:47:55
Cell Membranes Contain Lipid Bilayers
1:48:41
Cell Membranes Contain Lipid Bilayers
1:48:42
Bilayer Acts as Barrier to Movement In/Out of Cell
1:50:24
Bilayer Acts as Barrier to Movement In/Out of Cell
1:50:25
Organic Chemistry Meets Biology… Biochemistry!
1:51:12
Organic Chemistry Meets Biology… Biochemistry!
1:51:13
Polymers

45m 47s

Intro
0:00
Polymers
0:05
Monomer to Polymer: Vinyl Chloride to Polyvinyl Chloride
0:06
Polymer Properties
1:32
Polymer Properties
1:33
Natural Polymers: Rubber
2:30
Vulcanization
2:31
Natural Polymers: Polysaccharides
4:55
Example: Starch
4:56
Example: Cellulose
5:45
Natural Polymers: Proteins
6:07
Example: Keratin
6:08
DNA Strands
7:15
DNA Strands
7:16
Synthetic Polymers
8:30
Ethylene & Polyethylene: Lightweight Insulator & Airtight Plastic
8:31
Synthetic Organic Polymers
12:22
Polyethylene
12:28
Polyvinyl Chloride (PVC)
12:54
Polystyrene
13:28
Polyamide
14:34
Polymethyl Methacrylate
14:57
Kevlar
15:25
Synthetic Material Examples
16:30
How are Polymers Made?
21:00
Chain-growth Polymers Additions to Alkenes can be Radical, Cationic or Anionic
21:01
Chain Branching
22:34
Chain Branching
22:35
Special Reaction Conditions Prevent Branching
24:28
Ziegler-Natta Catalyst
24:29
Chain-Growth by Cationic Polymerization
27:35
Chain-Growth by Cationic Polymerization
27:36
Chain-Growth by Anionic Polymerization
29:35
Chain-Growth by Anionic Polymerization
29:36
Step-Growth Polymerization: Polyamides
32:16
Step-Growth Polymerization: Polyamides
32:17
Step-Growth Polymerization: Polyesters
34:23
Step-Growth Polymerization: Polyesters
34:24
Step-Growth Polymerization: Polycarbonates
35:56
Step-Growth Polymerization: Polycarbonates
35:57
Step-Growth Polymerization: Polyurethanes
37:18
Step-Growth Polymerization: Polyurethanes
37:19
Modifying Polymer Properties
39:35
Glass Transition Temperature
40:04
Crosslinking
40:42
Copolymers
40:58
Additives: Stabilizers
42:08
Additives: Flame Retardants
43:03
Additives: Plasticizers
43:41
Additives: Colorants
44:54
XII. Organic Synthesis
Organic Synthesis Strategies

2h 20m 24s

Intro
0:00
Organic Synthesis Strategies
0:15
Goal
0:16
Strategy
0:29
Example of a RetroSynthesis
1:30
Finding Starting Materials for Target Molecule
1:31
Synthesis Using Starting Materials
4:56
Synthesis of Alcohols by Functional Group Interconversion (FGI)
6:00
Synthesis of Alcohols by Functional Group Interconversion Overview
6:01
Alcohols by Reduction
7:43
Ketone to Alcohols
7:45
Aldehyde to Alcohols
8:26
Carboxylic Acid Derivative to Alcohols
8:36
Alcohols by Hydration of Alkenes
9:28
Hydration of Alkenes Using H₃O⁺
9:29
Oxymercuration-Demercuration
10:35
Hydroboration Oxidation
11:02
Alcohols by Substitution
11:42
Primary Alkyl Halide to Alcohols Using NaOH
11:43
Secondary Alkyl Halide to Alcohols Using Sodium Acetate
13:07
Tertiary Alkyl Halide to Alcohols Using H₂O
15:08
Synthesis of Alcohols by Forming a New C-C Bond
15:47
Recall: Alcohol & RMgBr
15:48
Retrosynthesis
17:28
Other Alcohol Disconnections
19:46
19:47
Synthesis Using PhMGgBr: Example 2
23:05
Synthesis of Alkyl Halides
26:06
Synthesis of Alkyl Halides Overview
26:07
Synthesis of Alkyl Halides by Free Radical Halogenation
27:04
Synthesis of Alkyl Halides by Free Radical Halogenation
27:05
Synthesis of Alkyl Halides by Substitution
29:06
Alcohol to Alkyl Halides Using HBr or HCl
29:07
Alcohol to Alkyl Halides Using SOCl₂
30:57
Alcohol to Alkyl Halides Using PBr₃ and Using P, I₂
31:03
Synthesis of Alkyl Halides by Addition
32:02
Alkene to Alkyl Halides Using HBr
32:03
Alkene to Alkyl Halides Using HBr & ROOR (Peroxides)
32:35
Example: Synthesis of Alkyl Halide
34:18
Example: Synthesis of Alkyl Halide
34:19
Synthesis of Ethers
39:25
Synthesis of Ethers
39:26
Example: Synthesis of an Ether
41:12
Synthesize TBME (t-butyl methyl ether) from Alcohol Starting Materials
41:13
Synthesis of Amines
46:05
Synthesis of Amines
46:06
Gabriel Synthesis of Amines
47:57
Gabriel Synthesis of Amines
47:58
Amines by SN2 with Azide Nu:
49:50
Amines by SN2 with Azide Nu:
49:51
Amines by SN2 with Cyanide Nu:
50:31
Amines by SN2 with Cyanide Nu:
50:32
Amines by Reduction of Amides
51:30
Amines by Reduction of Amides
51:31
Reductive Amination of Ketones/Aldehydes
52:42
Reductive Amination of Ketones/Aldehydes
52:43
Example : Synthesis of an Amine
53:47
Example 1: Synthesis of an Amine
53:48
Example 2: Synthesis of an Amine
56:16
Synthesis of Alkenes
58:20
Synthesis of Alkenes Overview
58:21
Synthesis of Alkenes by Elimination
59:04
Synthesis of Alkenes by Elimination Using NaOH & Heat
59:05
Synthesis of Alkenes by Elimination Using H₂SO₄ & Heat
59:57
Synthesis of Alkenes by Reduction
1:02:05
Alkyne to Cis Alkene
1:02:06
Alkyne to Trans Alkene
1:02:56
Synthesis of Alkenes by Wittig Reaction
1:03:46
Synthesis of Alkenes by Wittig Reaction
1:03:47
Retrosynthesis of an Alkene
1:05:35
Example: Synthesis of an Alkene
1:06:57
Example: Synthesis of an Alkene
1:06:58
Making a Wittig Reagent
1:10:31
Synthesis of Alkynes
1:13:09
Synthesis of Alkynes
1:13:10
Synthesis of Alkynes by Elimination (FGI)
1:13:42
First Step: Bromination of Alkene
1:13:43
Second Step: KOH Heat
1:14:22
Synthesis of Alkynes by Alkylation
1:15:02
Synthesis of Alkynes by Alkylation
1:15:03
Retrosynthesis of an Alkyne
1:16:18
Example: Synthesis of an Alkyne
1:17:40
Example: Synthesis of an Alkyne
1:17:41
Synthesis of Alkanes
1:20:52
Synthesis of Alkanes
1:20:53
Synthesis of Aldehydes & Ketones
1:21:38
Oxidation of Alcohol Using PCC or Swern
1:21:39
Oxidation of Alkene Using 1) O₃, 2)Zn
1:22:42
Reduction of Acid Chloride & Nitrile Using DiBAL-H
1:23:25
Hydration of Alkynes
1:24:55
Synthesis of Ketones by Acyl Substitution
1:26:12
Reaction with R'₂CuLi
1:26:13
Reaction with R'MgBr
1:27:13
Synthesis of Aldehydes & Ketones by α-Alkylation
1:28:00
Synthesis of Aldehydes & Ketones by α-Alkylation
1:28:01
Retrosynthesis of a Ketone
1:30:10
Acetoacetate Ester Synthesis of Ketones
1:31:05
Acetoacetate Ester Synthesis of Ketones: Step 1
1:31:06
Acetoacetate Ester Synthesis of Ketones: Step 2
1:32:13
Acetoacetate Ester Synthesis of Ketones: Step 3
1:32:50
Example: Synthesis of a Ketone
1:34:11
Example: Synthesis of a Ketone
1:34:12
Synthesis of Carboxylic Acids
1:37:15
Synthesis of Carboxylic Acids
1:37:16
Example: Synthesis of a Carboxylic Acid
1:37:59
Example: Synthesis of a Carboxylic Acid (Option 1)
1:38:00
Example: Synthesis of a Carboxylic Acid (Option 2)
1:40:51
Malonic Ester Synthesis of Carboxylic Acid
1:42:34
Malonic Ester Synthesis of Carboxylic Acid: Step 1
1:42:35
Malonic Ester Synthesis of Carboxylic Acid: Step 2
1:43:36
Malonic Ester Synthesis of Carboxylic Acid: Step 3
1:44:01
Example: Synthesis of a Carboxylic Acid
1:44:53
Example: Synthesis of a Carboxylic Acid
1:44:54
Synthesis of Carboxylic Acid Derivatives
1:48:05
Synthesis of Carboxylic Acid Derivatives
1:48:06
Alternate Ester Synthesis
1:48:58
Using Fischer Esterification
1:48:59
Using SN2 Reaction
1:50:18
Using Diazomethane
1:50:56
Using 1) LDA, 2) R'-X
1:52:15
Practice: Synthesis of an Alkyl Chloride
1:53:11
Practice: Synthesis of an Alkyl Chloride
1:53:12
Patterns of Functional Groups in Target Molecules
1:59:53
Recall: Aldol Reaction
1:59:54
β-hydroxy Ketone Target Molecule
2:01:12
α,β-unsaturated Ketone Target Molecule
2:02:20
Patterns of Functional Groups in Target Molecules
2:03:15
Recall: Michael Reaction
2:03:16
Retrosynthesis: 1,5-dicarbonyl Target Molecule
2:04:07
Patterns of Functional Groups in Target Molecules
2:06:38
Recall: Claisen Condensation
2:06:39
Retrosynthesis: β-ketoester Target Molecule
2:07:30
2-Group Target Molecule Summary
2:09:03
2-Group Target Molecule Summary
2:09:04
Example: Synthesis of Epoxy Ketone
2:11:19
Synthesize the Following Target Molecule from Cyclohexanone: Part 1 - Retrosynthesis
2:11:20
Synthesize the Following Target Molecule from Cyclohexanone: Part 2 - Synthesis
2:14:10
Example: Synthesis of a Diketone
2:16:57
Synthesis of a Diketone: Step 1 - Retrosynthesis
2:16:58
Synthesis of a Diketone: Step 2 - Synthesis
2:18:51
XII. Organic Synthesis & Organic Analysis
Organic Analysis: Classical & Modern Methods

46m 46s

Intro
0:00
Organic Analysis: Classical Methods
0:17
Classical Methods for Identifying Chemicals
0:18
Organic Analysis: Classical Methods
2:21
When is Structure Identification Needed?
2:22
Organic Analysis: Classical Methods
6:17
Classical Methods of Structure Identification: Physical Appearance
6:18
Classical Methods of Structure Identification: Physical Constants
6:42
Organic Analysis: Classical Methods
7:37
Classical Methods of Structure Identification: Solubility Tests - Water
7:38
Organic Analysis: Classical Methods
10:51
Classical Methods of Structure Identification: Solubility Tests - 5% aq. HCl Basic FG (Amines)
10:52
Organic Analysis: Classical Methods
11:50
Classical Methods of Structure Identification: Solubility Tests - 5% aq. NaOH Acidic FG (Carboxylic Acids, Phenols)
11:51
Organic Analysis: Classical Methods
13:28
Classical Methods of Structure Identification: Solubility Tests - 5% aq. NaHCO3 Strongly Acidic FG (Carboxylic Acids)
13:29
Organic Analysis: Classical Methods
15:35
Classical Methods of Structure Identification: Solubility Tests - Insoluble in All of the Above
15:36
Organic Analysis: Classical Methods
16:49
Classical Methods of Structure Identification: Idoform Test for Methyl Ketones
16:50
Organic Analysis: Classical Methods
22:02
Classical Methods of Structure Identification: Tollens' Test or Fehling's Solution for Aldehydes
22:03
Organic Analysis: Classical Methods
25:01
Useful Application of Classical Methods: Glucose Oxidase on Glucose Test Strips
25:02
Organic Analysis: Classical Methods
26:26
Classical Methods of Structure Identification: Starch-iodide Test
26:27
Organic Analysis: Classical Methods
28:22
Classical Methods of Structure Identification: Lucas Reagent to Determine Primary/Secondary/Tertiary Alcohol
28:23
Organic Analysis: Classical Methods
31:35
Classical Methods of Structure Identification: Silver Nitrate Test for Alkyl Halides
31:36
Organic Analysis: Classical Methods
33:23
Preparation of Derivatives
33:24
Organic Analysis: Modern Methods
36:55
Modern Methods of Chemical Characterization
36:56
Organic Analysis: Modern Methods
40:36
Checklist for Manuscripts Submitted to the ACS Journal Organic Letters
40:37
Organic Analysis: Modern Methods
42:39
Checklist for Manuscripts Submitted to the ACS Journal Organic Letters
42:40
Analysis of Stereochemistry

1h 2m 52s

Intro
0:00
Chirality & Optical Activity
0:32
Levorotatory & Dextrorotatory
0:33
Example: Optically Active?
2:22
Example: Optically Active?
2:23
Measurement of Specific Rotation, [α]
5:09
Measurement of Specific Rotation, [α]
5:10
Example: Calculation of Specific Rotation
8:56
Example: Calculation of Specific Rotation
8:57
Variability of Specific Rotation, [α]
12:52
Variability of Specific Rotation, [α]
12:53
Other Measures of Optical Activity: ORD and CD
15:04
Optical Rotary Dispersion (ORD)
15:05
Circular Dischroism (CD)
18:32
Circular Dischroism (CD)
18:33
Mixtures of Enantiomers
20:16
Racemic Mixtures
20:17
Unequal Mixtures of Enantiomers
21:36
100% ee
22:48
0% ee
23:34
Example: Definition of ee?
24:00
Example: Definition of ee?
24:01
Analysis of Optical Purity: [α]
27:47
[α] Measurement Can Be Used for Known Compounds
27:48
Analysis of Optical Purity: [α]
34:30
NMR Methods Using a Chiral Derivatizing Agent (CDA): Mosher's Reagent
34:31
Analysis of Optical Purity: [α]
40:01
NMR Methods Using a Chiral Derivatizing Agent (CDA): CDA Salt Formation
40:02
Analysis of Optical Purity: Chromatography
42:46
Chiral Chromatography
42:47
Stereochemistry Analysis by NMR: J Values (Coupling Constant)
51:28
NMR Methods for Structure Determination
51:29
Stereochemistry Analysis by NRM: NOE
57:00
NOE - Nuclear Overhauser Effect ( 2D Versions: NOESY or ROESY)
57:01
XIII. Spectroscopy
Infrared Spectroscopy, Part I

1h 4m

Intro
0:00
Infrared (IR) Spectroscopy
0:09
Introduction to Infrared (IR) Spectroscopy
0:10
Intensity of Absorption Is Proportional to Change in Dipole
3:08
IR Spectrum of an Alkane
6:08
Pentane
6:09
IR Spectrum of an Alkene
13:12
1-Pentene
13:13
IR Spectrum of an Alkyne
15:49
1-Pentyne
15:50
IR Spectrum of an Aromatic Compound
18:02
Methylbenzene
18:24
IR of Substituted Aromatic Compounds
24:04
IR of Substituted Aromatic Compounds
24:05
IR Spectrum of 1,2-Disubstituted Aromatic
25:30
1,2-dimethylbenzene
25:31
IR Spectrum of 1,3-Disubstituted Aromatic
27:15
1,3-dimethylbenzene
27:16
IR Spectrum of 1,4-Disubstituted Aromatic
28:41
1,4-dimethylbenzene
28:42
IR Spectrum of an Alcohol
29:34
1-pentanol
29:35
IR Spectrum of an Amine
32:39
1-butanamine
32:40
IR Spectrum of a 2° Amine
34:50
Diethylamine
34:51
IR Spectrum of a 3° Amine
35:47
Triethylamine
35:48
IR Spectrum of a Ketone
36:41
2-butanone
36:42
IR Spectrum of an Aldehyde
40:10
Pentanal
40:11
IR Spectrum of an Ester
42:38
Butyl Propanoate
42:39
IR Spectrum of a Carboxylic Acid
44:26
Butanoic Acid
44:27
Sample IR Correlation Chart
47:36
Sample IR Correlation Chart: Wavenumber and Functional Group
47:37
Predicting IR Spectra: Sample Structures
52:06
Example 1
52:07
Example 2
53:29
Example 3
54:40
Example 4
57:08
Example 5
58:31
Example 6
59:07
Example 7
1:00:52
Example 8
1:02:20
Infrared Spectroscopy, Part II

48m 34s

Intro
0:00
Interpretation of IR Spectra: a Basic Approach
0:05
Interpretation of IR Spectra: a Basic Approach
0:06
Other Peaks to Look for
3:39
Examples
5:17
Example 1
5:18
Example 2
9:09
Example 3
11:52
Example 4
14:03
Example 5
16:31
Example 6
19:31
Example 7
22:32
Example 8
24:39
IR Problems Part 1
28:11
IR Problem 1
28:12
IR Problem 2
31:14
IR Problem 3
32:59
IR Problem 4
34:23
IR Problem 5
35:49
IR Problem 6
38:20
IR Problems Part 2
42:36
IR Problem 7
42:37
IR Problem 8
44:02
IR Problem 9
45:07
IR Problems10
46:10
Nuclear Magnetic Resonance (NMR) Spectroscopy, Part I

1h 32m 14s

Intro
0:00
Purpose of NMR
0:14
Purpose of NMR
0:15
How NMR Works
2:17
How NMR Works
2:18
Information Obtained From a ¹H NMR Spectrum
5:51
No. of Signals, Integration, Chemical Shifts, and Splitting Patterns
5:52
Number of Signals in NMR (Chemical Equivalence)
7:52
Example 1: How Many Signals in ¹H NMR?
7:53
Example 2: How Many Signals in ¹H NMR?
9:36
Example 3: How Many Signals in ¹H NMR?
12:15
Example 4: How Many Signals in ¹H NMR?
13:47
Example 5: How Many Signals in ¹H NMR?
16:12
Size of Signals in NMR (Peak Area or Integration)
21:23
Size of Signals in NMR (Peak Area or Integration)
21:24
Using Integral Trails
25:15
Example 1: C₈H₁₈O
25:16
Example 2: C₃H₈O
27:17
Example 3: C₇H₈
28:21
Location of NMR Signal (Chemical Shift)
29:05
Location of NMR Signal (Chemical Shift)
29:06
¹H NMR Chemical Shifts
33:20
¹H NMR Chemical Shifts
33:21
¹H NMR Chemical Shifts (Protons on Carbon)
37:03
¹H NMR Chemical Shifts (Protons on Carbon)
37:04
Chemical Shifts of H's on N or O
39:01
Chemical Shifts of H's on N or O
39:02
Estimating Chemical Shifts
41:13
Example 1: Estimating Chemical Shifts
41:14
Example 2: Estimating Chemical Shifts
43:22
Functional Group Effects are Additive
45:28
Calculating Chemical Shifts
47:38
Methylene Calculation
47:39
Methine Calculation
48:20
Protons on sp³ Carbons: Chemical Shift Calculation Table
48:50
Example: Estimate the Chemical Shift of the Selected H
50:29
Effects of Resonance on Chemical Shifts
53:11
Example 1: Effects of Resonance on Chemical Shifts
53:12
Example 2: Effects of Resonance on Chemical Shifts
55:09
Example 3: Effects of Resonance on Chemical Shifts
57:08
Shape of NMR Signal (Splitting Patterns)
59:17
Shape of NMR Signal (Splitting Patterns)
59:18
Understanding Splitting Patterns: The 'n+1 Rule'
1:01:24
Understanding Splitting Patterns: The 'n+1 Rule'
1:01:25
Explanation of n+1 Rule
1:02:42
Explanation of n+1 Rule: One Neighbor
1:02:43
Explanation of n+1 Rule: Two Neighbors
1:06:23
Summary of Splitting Patterns
1:06:24
Summary of Splitting Patterns
1:10:45
Predicting ¹H NMR Spectra
1:10:46
Example 1: Predicting ¹H NMR Spectra
1:13:30
Example 2: Predicting ¹H NMR Spectra
1:19:07
Example 3: Predicting ¹H NMR Spectra
1:23:50
Example 4: Predicting ¹H NMR Spectra
1:29:27
Nuclear Magnetic Resonance (NMR) Spectroscopy, Part II

2h 3m 48s

Intro
0:00
¹H NMR Problem-Solving Strategies
0:18
Step 1: Analyze IR Spectrum (If Provided)
0:19
Step 2: Analyze Molecular Formula (If Provided)
2:06
Step 3: Draw Pieces of Molecule
3:49
Step 4: Confirm Pieces
6:30
Step 5: Put the Pieces Together!
7:23
Step 6: Check Your Answer!
8:21
Examples
9:17
Example 1: Determine the Structure of a C₉H₁₀O₂ Compound with the Following ¹H NMR Data
9:18
Example 2: Determine the Structure of a C₉H₁₀O₂ Compound with the Following ¹H NMR Data
17:27
¹H NMR Practice
20:57
¹H NMR Practice 1: C₁₀H₁₄
20:58
¹H NMR Practice 2: C₄H₈O₂
29:50
¹H NMR Practice 3: C₆H₁₂O₃
39:19
¹H NMR Practice 4: C₈H₁₈
50:19
More About Coupling Constants (J Values)
57:11
Vicinal (3-bond) and Geminal (2-bond)
57:12
Cyclohexane (ax-ax) and Cyclohexane (ax-eq) or (eq-eq)
59:50
Geminal (Alkene), Cis (Alkene), and Trans (Alkene)
1:02:40
Allylic (4-bond) and W-coupling (4-bond) (Rigid Structures Only)
1:04:05
¹H NMR Advanced Splitting Patterns
1:05:39
Example 1: ¹H NMR Advanced Splitting Patterns
1:05:40
Example 2: ¹H NMR Advanced Splitting Patterns
1:10:01
Example 3: ¹H NMR Advanced Splitting Patterns
1:13:45
¹H NMR Practice
1:22:53
¹H NMR Practice 5: C₁₁H₁₇N
1:22:54
¹H NMR Practice 6: C₉H₁₀O
1:34:04
¹³C NMR Spectroscopy
1:44:49
¹³C NMR Spectroscopy
1:44:50
¹³C NMR Chemical Shifts
1:47:24
¹³C NMR Chemical Shifts Part 1
1:47:25
¹³C NMR Chemical Shifts Part 2
1:48:59
¹³C NMR Practice
1:50:16
¹³C NMR Practice 1
1:50:17
¹³C NMR Practice 2
1:58:30
C-13 DEPT NMR Experiments

23m 10s

Intro
0:00
C-13 DEPT NMR Spectoscopy
0:13
Overview
0:14
C-13 DEPT NMR Spectoscopy, Cont.
3:31
Match C-13 Peaks to Carbons on Structure
3:32
C-13 DEPT NMR Spectoscopy, Cont.
8:46
Predict the DEPT-90 and DEPT-135 Spectra for the Given Compound
8:47
C-13 DEPT NMR Spectoscopy, Cont.
12:30
Predict the DEPT-90 and DEPT-135 Spectra for the Given Compound
12:31
C-13 DEPT NMR Spectoscopy, Cont.
17:19
Determine the Structure of an Unknown Compound using IR Spectrum and C-13 DEPT NMR
17:20
Two-Dimensional NMR Techniques: COSY

33m 39s

Intro
0:00
Two-Dimensional NMR Techniques: COSY
0:14
How Do We Determine Which Protons are Related in the NMR?
0:15
Two-Dimensional NMR Techniques: COSY
1:48
COSY Spectra
1:49
Two-Dimensional NMR Techniques: COSY
7:00
COSY Correlation
7:01
Two-Dimensional NMR Techniques: COSY
8:55
Complete the COSY NMR Spectrum for the Given Compoun
8:56
NMR Practice Problem
15:40
Provide a Structure for the Unknown Compound with the H NMR and COSY Spectra Shown
15:41
Two-Dimensional NMR Techniques: HETCOR & HMBC

15m 5s

Intro
0:00
HETCOR
0:15
Heteronuclear Correlation Spectroscopy
0:16
HETCOR
2:04
HETCOR Example
2:05
HMBC
11:07
Heteronuclear Multiple Bond Correlation
11:08
HMBC
13:14
HMB Example
13:15
Mass Spectrometry

1h 28m 35s

Intro
0:00
Introduction to Mass Spectrometry
0:37
Uses of Mass Spectrometry: Molecular Mass
0:38
Uses of Mass Spectrometry: Molecular Formula
1:04
Uses of Mass Spectrometry: Structural Information
1:21
Uses of Mass Spectrometry: In Conjunction with Gas Chromatography
2:03
Obtaining a Mass Spectrum
2:59
Obtaining a Mass Spectrum
3:00
The Components of a Mass Spectrum
6:44
The Components of a Mass Spectrum
6:45
What is the Mass of a Single Molecule
12:13
Example: CH₄
12:14
Example: ¹³CH₄
12:51
What Ratio is Expected for the Molecular Ion Peaks of C₂H₆?
14:20
Other Isotopes of High Abundance
16:30
Example: Cl Atoms
16:31
Example: Br Atoms
18:33
Mass Spectrometry of Chloroethane
19:22
Mass Spectrometry of Bromobutane
21:23
Isotopic Abundance can be Calculated
22:48
What Ratios are Expected for the Molecular Ion Peaks of CH₂Br₂?
22:49
Determining Molecular Formula from High-resolution Mass Spectrometry
26:53
Exact Masses of Various Elements
26:54
Fragmentation of various Functional Groups
28:42
What is More Stable, a Carbocation C⁺ or a Radical R?
28:43
Fragmentation is More Likely If It Gives Relatively Stable Carbocations and Radicals
31:37
Mass Spectra of Alkanes
33:15
Example: Hexane
33:16
Fragmentation Method 1
34:19
Fragmentation Method 2
35:46
Fragmentation Method 3
36:15
Mass of Common Fragments
37:07
Mass of Common Fragments
37:08
Mass Spectra of Alkanes
39:28
Mass Spectra of Alkanes
39:29
What are the Peaks at m/z 15 and 71 So Small?
41:01
Branched Alkanes
43:12
Explain Why the Base Peak of 2-methylhexane is at m/z 43 (M-57)
43:13
Mass Spectra of Alkenes
45:42
Mass Spectra of Alkenes: Remove 1 e⁻
45:43
Mass Spectra of Alkenes: Fragment
46:14
High-Energy Pi Electron is Most Likely Removed
47:59
Mass Spectra of Aromatic Compounds
49:01
Mass Spectra of Aromatic Compounds
49:02
Mass Spectra of Alcohols
51:32
Mass Spectra of Alcohols
51:33
Mass Spectra of Ethers
54:53
Mass Spectra of Ethers
54:54
Mass Spectra of Amines
56:49
Mass Spectra of Amines
56:50
Mass Spectra of Aldehydes & Ketones
59:23
Mass Spectra of Aldehydes & Ketones
59:24
McLafferty Rearrangement
1:01:29
McLafferty Rearrangement
1:01:30
Mass Spectra of Esters
1:04:15
Mass Spectra of Esters
1:01:16
Mass Spectrometry Discussion I
1:05:01
For the Given Molecule (M=58), Do You Expect the More Abundant Peak to Be m/z 15 or m/z 43?
1:05:02
Mass Spectrometry Discussion II
1:08:13
For the Given Molecule (M=74), Do You Expect the More Abundant Peak to Be m/z 31, m/z 45, or m/z 59?
1:08:14
Mass Spectrometry Discussion III
1:11:42
Explain Why the Mass Spectra of Methyl Ketones Typically have a Peak at m/z 43
1:11:43
Mass Spectrometry Discussion IV
1:14:46
In the Mass Spectrum of the Given Molecule (M=88), Account for the Peaks at m/z 45 and m/z 57
1:14:47
Mass Spectrometry Discussion V
1:18:25
How Could You Use Mass Spectrometry to Distinguish Between the Following Two Compounds (M=73)?
1:18:26
Mass Spectrometry Discussion VI
1:22:45
What Would be the m/z Ratio for the Fragment for the Fragment Resulting from a McLafferty Rearrangement for the Following Molecule (M=114)?
1:22:46
XIV. Organic Chemistry Lab
Completing the Reagent Table for Prelab

21m 9s

Intro
0:00
Sample Reagent Table
0:11
Reagent Table Overview
0:12
Calculate Moles of 2-bromoaniline
6:44
Calculate Molar Amounts of Each Reagent
9:20
Calculate Mole of NaNO₂
9:21
Calculate Moles of KI
10:33
Identify the Limiting Reagent
11:17
Which Reagent is the Limiting Reagent?
11:18
Calculate Molar Equivalents
13:37
Molar Equivalents
13:38
Calculate Theoretical Yield
16:40
Theoretical Yield
16:41
Calculate Actual Yield (%Yield)
18:30
Actual Yield (%Yield)
18:31
Introduction to Melting Points

16m 10s

Intro
0:00
Definition of a Melting Point (mp)
0:04
Definition of a Melting Point (mp)
0:05
Solid Samples Melt Gradually
1:49
Recording Range of Melting Temperature
2:04
Melting Point Theory
3:14
Melting Point Theory
3:15
Effects of Impurities on a Melting Point
3:57
Effects of Impurities on a Melting Point
3:58
Special Exception: Eutectic Mixtures
5:09
Freezing Point Depression by Solutes
5:39
Melting Point Uses
6:19
Solid Compound
6:20
Determine Purity of a Sample
6:42
Identify an Unknown Solid
7:06
Recording a Melting Point
9:03
Pack 1-3 mm of Dry Powder in MP Tube
9:04
Slowly Heat Sample
9:55
Record Temperature at First Sign of Melting
10:33
Record Temperature When Last Crystal Disappears
11:26
Discard MP Tube in Glass Waste
11:32
Determine Approximate MP
11:42
Tips, Tricks and Warnings
12:28
Use Small, Tightly Packed Sample
12:29
Be Sure MP Apparatus is Cool
12:45
Never Reuse a MP Tube
13:16
Sample May Decompose
13:30
If Pure Melting Point (MP) Doesn't Match Literature
14:20
Melting Point Lab

8m 17s

Intro
0:00
Melting Point Tubes
0:40
Melting Point Apparatus
3:42
Recording a melting Point
5:50
Introduction to Recrystallization

22m

Intro
0:00
Crystallization to Purify a Solid
0:10
Crude Solid
0:11
Hot Solution
0:20
Crystals
1:09
Supernatant Liquid
1:20
Theory of Crystallization
2:34
Theory of Crystallization
2:35
Analysis and Obtaining a Second Crop
3:40
Crystals → Melting Point, TLC
3:41
Supernatant Liquid → Crude Solid → Pure Solid
4:18
Crystallize Again → Pure Solid (2nd Crop)
4:32
Choosing a Solvent
5:19
1. Product is Very Soluble at High Temperatures
5:20
2. Product has Low Solubility at Low Temperatures
6:00
3. Impurities are Soluble at All Temperatures
6:16
Check Handbooks for Suitable Solvents
7:33
Why Isn't This Dissolving?!
8:46
If Solid Remains When Solution is Hot
8:47
Still Not Dissolved in Hot Solvent?
10:18
Where Are My Crystals?!
12:23
If No Crystals Form When Solution is Cooled
12:24
Still No Crystals?
14:59
Tips, Tricks and Warnings
16:26
Always Use a Boiling Chip or Stick!
16:27
Use Charcoal to Remove Colored Impurities
16:52
Solvent Pairs May Be Used
18:23
Product May 'Oil Out'
20:11
Recrystallization Lab

19m 7s

Intro
0:00
Step 1: Dissolving the Solute in the Solvent
0:12
Hot Filtration
6:33
Step 2: Cooling the Solution
8:01
Step 3: Filtering the Crystals
12:08
Step 4: Removing & Drying the Crystals
16:10
Introduction to Distillation

25m 54s

Intro
0:00
Distillation: Purify a Liquid
0:04
Simple Distillation
0:05
Fractional Distillation
0:55
Theory of Distillation
1:04
Theory of Distillation
1:05
Vapor Pressure and Volatility
1:52
Vapor Pressure
1:53
Volatile Liquid
2:28
Less Volatile Liquid
3:09
Vapor Pressure vs. Boiling Point
4:03
Vapor Pressure vs. Boiling Point
4:04
Increasing Vapor Pressure
4:38
The Purpose of Boiling Chips
6:46
The Purpose of Boiling Chips
6:47
Homogeneous Mixtures of Liquids
9:24
Dalton's Law
9:25
Raoult's Law
10:27
Distilling a Mixture of Two Liquids
11:41
Distilling a Mixture of Two Liquids
11:42
Simple Distillation: Changing Vapor Composition
12:06
Vapor & Liquid
12:07
Simple Distillation: Changing Vapor Composition
14:47
Azeotrope
18:41
Fractional Distillation: Constant Vapor Composition
19:42
Fractional Distillation: Constant Vapor Composition
19:43
Distillation Lab

24m 13s

Intro
0:00
Glassware Overview
0:04
Heating a Sample
3:09
Bunsen Burner
3:10
Heating Mantle 1
4:45
Heating Mantle 2
6:18
Hot Plate
7:10
Simple Distillation Lab
8:37
Fractional Distillation Lab
17:13
Removing the Distillation Set-Up
22:41
Introduction to TLC (Thin-Layer Chromatography)

28m 51s

Intro
0:00
Chromatography
0:06
Purification & Analysis
0:07
Types of Chromatography: Thin-layer, Column, Gas, & High Performance Liquid
0:24
Theory of Chromatography
0:44
Theory of Chromatography
0:45
Performing a Thin-layer Chromatography (TLC) Analysis
2:30
Overview: Thin-layer Chromatography (TLC) Analysis
2:31
Step 1: 'Spot' the TLC Plate
4:11
Step 2: Prepare the Developing Chamber
5:54
Step 3: Develop the TLC Plate
7:30
Step 4: Visualize the Spots
9:02
Step 5: Calculate the Rf for Each Spot
12:00
Compound Polarity: Effect on Rf
16:50
Compound Polarity: Effect on Rf
16:51
Solvent Polarity: Effect on Rf
18:47
Solvent Polarity: Effect on Rf
18:48
Example: EtOAc & Hexane
19:35
Other Types of Chromatography
22:27
Thin-layer Chromatography (TLC)
22:28
Column Chromatography
22:56
High Performance Liquid (HPLC)
23:59
Gas Chromatography (GC)
24:38
Preparative 'prep' Scale Possible
28:05
TLC Analysis Lab

20m 50s

Intro
0:00
Step 1: 'Spot' the TLC Plate
0:06
Step 2: Prepare the Developing Chamber
4:06
Step 3: Develop the TLC Plate
6:26
Step 4: Visualize the Spots
7:45
Step 5: Calculate the Rf for Each Spot
11:48
How to Make Spotters
12:58
TLC Plate
16:04
Flash Column Chromatography
17:11
Introduction to Extractions

34m 25s

Intro
0:00
Extraction Purify, Separate Mixtures
0:07
Adding a Second Solvent
0:28
Mixing Two Layers
0:38
Layers Settle
0:54
Separate Layers
1:05
Extraction Uses
1:20
To Separate Based on Difference in Solubility/Polarity
1:21
To Separate Based on Differences in Reactivity
2:11
Separate & Isolate
2:20
Theory of Extraction
3:03
Aqueous & Organic Phases
3:04
Solubility: 'Like Dissolves Like'
3:25
Separation of Layers
4:06
Partitioning
4:14
Distribution Coefficient, K
5:03
Solutes Partition Between Phases
5:04
Distribution Coefficient, K at Equilibrium
6:27
Acid-Base Extractions
8:09
Organic Layer
8:10
Adding Aqueous HCl & Mixing Two Layers
8:46
Neutralize (Adding Aqueous NaOH)
10:05
Adding Organic Solvent Mix Two Layers 'Back Extract'
10:24
Final Results
10:43
Planning an Acid-Base Extraction, Part 1
11:01
Solute Type: Neutral
11:02
Aqueous Solution: Water
13:40
Solute Type: Basic
14:43
Solute Type: Weakly Acidic
15:23
Solute Type: Acidic
16:12
Planning an Acid-Base Extraction, Part 2
17:34
Planning an Acid-Base Extraction
17:35
Performing an Extraction
19:34
Pour Solution into Sep Funnel
19:35
Add Second Liquid
20:07
Add Stopper, Cover with Hand, Remove from Ring
20:48
Tip Upside Down, Open Stopcock to Vent Pressure
21:00
Shake to Mix Two Layers
21:30
Remove Stopper & Drain Bottom Layer
21:40
Reaction Work-up: Purify, Isolate Product
22:03
Typical Reaction is Run in Organic Solvent
22:04
Starting a Reaction Work-up
22:33
Extracting the Product with Organic Solvent
23:17
Combined Extracts are Washed
23:40
Organic Layer is 'Dried'
24:23
Finding the Product
26:38
Which Layer is Which?
26:39
Where is My Product?
28:00
Tips, Tricks and Warnings
29:29
Leaking Sep Funnel
29:30
Caution When Mixing Layers & Using Ether
30:17
If an Emulsion Forms
31:51
Extraction Lab

14m 49s

Intro
0:00
Step 1: Preparing the Separatory Funnel
0:03
Step 2: Adding Sample
1:18
Step 3: Mixing the Two Layers
2:59
Step 4: Draining the Bottom Layers
4:59
Step 5: Performing a Second Extraction
5:50
Step 6: Drying the Organic Layer
7:21
Step 7: Gravity Filtration
9:35
Possible Extraction Challenges
12:55
Loading...
This is a quick preview of the lesson. For full access, please Log In or Sign up.
For more information, please see full course syllabus of Organic Chemistry
  • Discussion

  • Study Guides

  • Practice Questions

  • Download Lecture Slides

  • Table of Contents

  • Transcription

  • Related Books & Services

Lecture Comments (32)

1 answer

Last reply by: Professor Starkey
Mon Apr 4, 2016 2:12 PM

Post by Jordan Arciniega on April 3, 2016

Hello Dr. Starkey,

During the acetal mechanism, the first step is protonation of the carbonyl oxygen. This results in the formal charge of the oxygen to be plus one.

But why exactly does this result in the carbon of the carbonyl group to be more electrophilic? Is it because the plus charge on the oxygen changes its electronegativity such that it pulls electron density even more to itself (inductive effect), leaving the carbon more positively charged? Or is it because the oxygen with the positive charge now favors the resonance form of a plus charge on the carbon (to make oxygen more happy)?

I guess in general, I would like to know if plus charges on atoms change the electronegativity of that atom. So if an atom becomes a plus 1 charge, will it attract more electron density towards itself compared to its neutral form?

Thanks in advance, and like always, I highly appreciate these extremely helpful lectures!

1 answer

Last reply by: Professor Starkey
Wed Mar 30, 2016 3:15 PM

Post by Jonathan Ibera on March 29, 2016

Thanks, your lecture are very clear.
For the clemmensen reduction of ketones and aldehydes all the way to alkane, can this reduction method reduce alcohol as well? I know this is kind of gray area as the mechanism of clemmensen reduction might not be clear to me.

1 answer

Last reply by: Professor Starkey
Thu Feb 25, 2016 12:46 PM

Post by Milki Hussen on February 25, 2016

Is it possible to use to use methanal + a 4 carbon grignard reagent to get the propanol on on retrosynthesis ( 28 minutes)?

1 answer

Last reply by: Professor Starkey
Tue Jan 26, 2016 9:27 PM

Post by Jason Smith on January 26, 2016

Hi professor. In the formation of acetals, the reason why the acid acts first is because it's faster? Thank you.

1 answer

Last reply by: Professor Starkey
Sun Dec 14, 2014 8:31 PM

Post by bea v on December 14, 2014

if an C=O bond is flaked by an oxygen on both side is it still more reactive than a C=C ?



1 answer

Last reply by: Professor Starkey
Wed Mar 19, 2014 9:13 PM

Post by Jude Nawlo on March 19, 2014

Hi Dr. Starkey,

Do the same concepts that apply in Wittig apply for Horner-Wadsworth Emmons reactions?

3 answers

Last reply by: Professor Starkey
Mon Mar 3, 2014 10:23 PM

Post by Florel Fraser on March 1, 2014

I am having problems with the portion of the video on Wittig Reagent.  As soon as Dr. Starkey starts the mechanism the video stops and goes back to the beginning of the lesson.

2 answers

Last reply by: Professor Starkey
Wed Jul 19, 2017 11:01 AM

Post by Victor Ye on May 27, 2013

I've really enjoyed your lessons, Prof. Starkey!! They're VERY helpful, and they're the best chemistry video lectures I've found!

I also second Nawaphan's comment about possibly covering biological molecules in your lessons. Educator has a biochemistry section, but I think lessons with a chemistry perspective would very useful for us. My OChem class covers these biological molecules, and the last three chapters of my textbook concern these topics. Thank you!

2 answers

Last reply by: Professor Starkey
Wed Jul 19, 2017 10:59 AM

Post by Nawaphan Jedjomnongkit on May 3, 2013

You are great teacher and this is the first time that I enjoy every ORG Chem lesson!! Now I can remember CTI because it's always come with sound ding ding ding!!!!! lol Thank you so much!! Is it possible to add some lessons about biological molecules like proteins, amino acids, carbohydrates and lipids?

1 answer

Last reply by: Professor Starkey
Sun May 20, 2012 10:13 AM

Post by Mark Deming on May 17, 2012

Wouldn't the grignard add twice so you should use lithium for first addition. That way you won't get two isopropyl groups?

0 answers

Post by Jason Jarduck on March 3, 2012

Hi Dr. Starkey,

Another great lecture. I have been taking notes and using your lectures for studying for tests and exams.

Thank You

Jason

1 answer

Last reply by: Professor Starkey
Wed Nov 30, 2011 11:13 PM

Post by ochemstarkey on November 30, 2011

Thank you so much Dr Starkey, the best OCHM teacher ever!!!

2 answers

Last reply by: Professor Starkey
Sat Nov 5, 2011 3:15 PM

Post by Clint Rapp on October 29, 2011

this is a Ketal because a ketone was the starting material? What is up with that?

1 answer

Last reply by: Professor Starkey
Sat Oct 8, 2011 3:01 PM

Post by Gayk Gevorkyan on October 5, 2011

Wouldn't be able to PASS OCHEM without this......THANK YOU DR.LAURIE!

Ketones

Draw the major product formed from this reaction:
Draw the major product formed from this reaction:
Draw the major product formed from this reaction:
Draw the major product formed from this reaction:
Draw the major product formed from this reaction:
Draw the major product formed from this reaction:

*These practice questions are only helpful when you work on them offline on a piece of paper and then use the solution steps function to check your answer.

Answer

Ketones

Lecture Slides are screen-captured images of important points in the lecture. Students can download and print out these lecture slide images to do practice problems as well as take notes while watching the lecture.

  1. Intro
    • Aldehydes & Ketones
    • The Carbonyl
    • Preparation/Synthesis of Aldehydes & Ketones
    • Reaction with Hydride Nu:
    • Reaction with Carbon Nu:
    • Reaction with Carbon Nu:
    • Retrosynthesis of Alcohols
    • Example
    • Example
    • Example
    • Example
    • Wittig Reaction
    • Preparation of Wittig Reagent
    • Wittig Retrosynthesis
    • Reaction with Oxygen Nu:
    • Reaction with Oxygen Nu:
    • Example
    • Mechanism for Acetal Formation
    • What is a CTI?
    • Acetals & Cyclic Acetals
    • Hydrolysis of Acetals: Regenerates Carbonyl
    • Reaction with Nitrogen Nu:
    • Mechanism of Imine Formation
    • Oxidation of Aldehydes
    • Reductions of Ketones and Aldehydes
    • Reductions of Ketones and Aldehydes
    • Acetals as Protective Groups
    • Example
    • Protective Groups
    • Example
    • Example: Another Route
    • Example
    • Example
    • Example
    • Example
    • Intro 0:00
    • Aldehydes & Ketones 0:11
      • The Carbonyl: Resonance & Inductive
      • Reactivity
    • The Carbonyl 2:35
      • The Carbonyl
      • Carbonyl FG's
    • Preparation/Synthesis of Aldehydes & Ketones 6:18
      • Oxidation of Alcohols
      • Ozonolysis of Alkenes
      • Hydration of Alkynes
    • Reaction with Hydride Nu: 9:00
      • Reaction with Hydride Nu:
    • Reaction with Carbon Nu: 11:29
      • Carbanions: Acetylide
      • Carbanions: Cyanide
    • Reaction with Carbon Nu: 15:32
      • Organometallic Reagents (RMgX, Rli)
    • Retrosynthesis of Alcohols 17:04
      • Retrosynthesis of Alcohols
    • Example 19:30
      • Example: Transform
    • Example 22:57
      • Example: Transform
    • Example 28:19
      • Example: Transform
    • Example 33:36
      • Example: Transform
    • Wittig Reaction 37:39
      • Wittig Reaction: A Resonance-Stabilized Carbanion (Nu:)
      • Wittig Reaction: Mechanism
    • Preparation of Wittig Reagent 41:58
      • Two Steps From RX
      • Example: Predict
    • Wittig Retrosynthesis 46:19
      • Wittig Retrosynthesis
      • Synthesis
    • Reaction with Oxygen Nu: 51:21
      • Addition of H₂O
      • Exception: Formaldehyde is 99% Hydrate in H₂O Solution
      • Exception: Hydrate is Favored if Partial Positive Near Carbonyl
    • Reaction with Oxygen Nu: 57:45
      • Addition of ROH
      • TsOH: Tosic Acid
      • Addition of ROH Cont.
    • Example 1:01:43
      • Predict
      • Mechanism
    • Mechanism for Acetal Formation 1:04:10
      • Mechanism for Acetal Formation
    • What is a CTI? 1:15:04
      • Tetrahedral Intermediate
      • Charged Tetrahedral Intermediate
      • CTI: Acid-cat
      • CTI: Base-cat
    • Acetals & Cyclic Acetals 1:17:49
      • Overall
      • Cyclic Acetals
    • Hydrolysis of Acetals: Regenerates Carbonyl 1:20:01
      • Hydrolysis of Acetals: Regenerates Carbonyl
      • Mechanism
    • Reaction with Nitrogen Nu: 1:30:11
      • Reaction with Nitrogen Nu:
      • Example
    • Mechanism of Imine Formation 1:33:24
      • Mechanism of Imine Formation
    • Oxidation of Aldehydes 1:38:12
      • Oxidation of Aldehydes 1
      • Oxidation of Aldehydes 2
      • Oxidation of Aldehydes 3
    • Reductions of Ketones and Aldehydes 1:40:54
      • Reductions of Ketones and Aldehydes
      • Hydride/ Workup
      • Raney Nickel
    • Reductions of Ketones and Aldehydes 1:43:24
      • Clemmensen Reduction & Wolff-Kishner Reduction
    • Acetals as Protective Groups 1:46:50
      • Acetals as Protective Groups
    • Example 1:50:39
      • Example: Consider the Following Synthesis
    • Protective Groups 1:54:47
      • Protective Groups
    • Example 1:59:02
      • Example: Transform
    • Example: Another Route 2:04:54
      • Example: Transform
    • Example 2:08:50
      • Transform
    • Example 2:11:05
      • Transform
    • Example 2:13:45
      • Transform
    • Example 2:15:43
      • Provide the Missing Starting Material

    Transcription: Ketones

    Welcome back to Educator.0000

    The next functional group we are going to take a look at contains two groups--either the ketone or the aldehyde--are going to have very similar reactivities; let's take a look at both of them.0002

    The ketones and aldehydes are molecules that contain the carbonyl; the C-O double bond is what we call a carbonyl.0013

    We are going to see that the aldehydes and ketones are the first of many carbonyl containing functional groups that we are going to be exploring.0020

    What is very special about the carbonyl is that it has resonance; anytime we have a π bond between two different atoms, we know that we can draw a resonance form.0028

    Where we take the π bond and we move it to the more electronegative atom; every carbonyl has a resonance contributor that has an O- and a C+.0037

    That combined with the inductive effects that we have for a carbon bonded to an oxygen means that overall every carbonyl has a significant δ- charge on the oxygen.0050

    And a significant δ+ on the carbon; that is going to define the reactivity of the carbonyl.0064

    For example, what do we associate with something that is partially positive?--it is going to be electrophilic; carbonyls are electrophilic.0069

    What does it mean to be an electrophile?--nucleophiles attack; nucleophiles add here; we are going to see again and again example after example of nucleophilic attack onto the carbonyl carbon.0076

    The oxygen is exceptionally partially negative, very electron rich, compared to an ordinary oxygen; that makes it basic; what does it mean to be a base?0090

    It means that you can protonate here; many of our mechanisms are going to begin with the carbonyl interacting with an acid and getting protonated on the carbonyl oxygen.0099

    Those are the reactivities we are going to start with in the next several units in looking at carbonyl chemistry.0110

    Eventually we are going to move into some reactivity not of the carbonyl carbon but of the next carbon over; this first carbon attached to the carbonyl is described as the α carbon.0116

    There is an interesting feature of the α carbon--is that the protons that are attached to that α carbon are acidic.0128

    What does it mean to be an acid?--it means you donate a proton; in other words, it can be deprotonated here.0134

    Eventually we are going to start looking at that α carbon and deprotonating in that position and seeing what reactions lead from there.0149

    Because of this resonance, the carbonyl is a very very stable functional group; that is what makes it ubiquitous.0159

    We find it all over the place in a wide variety of functional groups; it is extremely strong; it is extremely stable.0164

    If we take a look at the bond dissociation energy for a C-O single bond, it is 79 kcals per mole, an average of that.0171

    What would expect for a C-O double bond?--typically if you think about alkenes, we compare it to C-C single bond.0178

    When we added a π bond onto that, onto the σ bond, we didn't see a doubling of the bond strength because a π bond is typically weaker than a σ bond.0187

    What we might predict for the bond strength of a carbonyl if you were to try and break through the σ bond and the π bond, we would expect it to be less than maybe 160.0199

    This is about 80; so if we had two single bonds, two σ bonds, we would expect it to be 160; we would expect this to be a little less than this.0209

    It turns out that the carbonyl strength is 173 kcals per mole; it is actually stronger to have a C-O double bond than to have two separate C-O single bonds.0219

    This is extremely unusual; why is it so stable?--it is because it has that resonance energy; it has that resonance energy, resonance stabilization.0230

    Adding that π bond makes that resonance possible; that makes it a very energetically favorable thing and very strong bond.0242

    In fact what we are going to see a lot of times is formation of the carbonyl could be the driving force of the reaction.0250

    That might be something that helps decide whether or not a reaction is going to be favorable.0256

    Anytime we see a mechanistic step that creates a carbonyl as part of that step, we need to recognize that that is a very favorable step; that is a good step to happen.0260

    Like I said, we are going to start with just aldehydes and ketones; we call it a ketone when the R group on either side of the carbonyl is a carbon; that is called a ketone.0269

    When we have at least one hydrogen attached here, two hydrogens, or one carbon and a hydrogen, that is what we call an aldehyde.0281

    That is what we are going to start with in today's lesson--is looking at carbonyls that have nothing other than carbons or hydrogens attached to the carbonyl.0288

    But there is many other functional groups that contain carbonyls; this for example when we have an OH attached to a carbonyl, this is no longer an alcohol.0297

    The OH is part of this functional group; together the carbonyl and the OH are described as a carboxylic acid functional group; this is a carboxylic acid.0306

    When we have an OR group attached to a carbonyl, again it is no longer an ether; an ether would mean we have an OR attached to just a plain alkyl carbon group.0318

    But when it is attached to a carbonyl, we call these esters; when we have a nitrogen here; it is no longer an amine; we call this an amide; and so on.0328

    There is a variety of these compounds where attached to the carbonyl we have some group that has lone pairs attached to it.0336

    Just like the oxygen has lone pairs, nitrogen has lone pairs, halogens have lone pairs.0349

    Anytime we have this kind of a structure, these are all going to be related to each other; these are called carboxylic acid derivatives.0354

    Of course this first one is a carboxylic acid; all the others are described as carboxylic acid derivatives.0366

    After we are done talking about aldehydes and ketones, then we will move to these other related compounds.0372

    What are some ways that we can synthesize an aldehyde or a ketone; what reactions have we seen that generate C-O double bonds, carbonyls?0380

    One way we could do it is we could start with an alcohol; if we take an alcohol and we treat it with an oxidizing agent.0389

    We can increase our number of C-O bonds and decrease our number of C-H bonds; that is what our oxidation reactions look like.0395

    That would be a great way to form a carbonyl; we could get either an aldehyde or a ketone depending on what kind of alcohol we started with.0406

    We had things like PCC as an oxidizing agent; that could do this; or maybe Jones, sodium dichromate, Cr2O7, H2SO4; we had Swern oxidation.0414

    There are a variety of oxidizing agents we have seen before; certain situations gave us ketones; others gave us aldehydes as products.0427

    Another reaction we saw that has given carbonyl compounds as products is the ozonolysis of alkenes; ozonolysis means we react an alkene with ozone.0437

    It does a lysis; it cleaves the carbon-carbon double bond; what does it replace the carbon-carbon double bond with?--it replaces it with a carbon-oxygen double; it is replaced with a carbonyl.0446

    This is a way of making two carbonyl containing compounds; again it can be a combination of either aldehydes or ketones depending on what kind of alkene we started with here.0458

    I remember this DMS, this dimethyl sulfide, is just a reductive workup; the ozonolysis is always a two-step procedure to cleave the bond and form the carbonyls.0470

    One other reaction we have seen for creating carbonyls was doing hydration of alkynes; remember that if we add water across a π bond.0482

    We add an H and an OH across one of the π bonds, we get an enol; then that enol will tautomerize to a carbonyl, either a ketone or an aldehyde.0491

    We saw that if we were to add with Markovnikov regiochemistry, then the oxygen would go to the inside carbon and the hydrogen would go to the end carbon.0504

    In other words, we could get a ketone product here; or if we did hydroboration-oxidation, remember that was anti-Markovnikov addition of water.0516

    That would give us a product that has the carbonyl on the end carbon; in other words, we could use that to make an aldehyde.0525

    So an alkyne might be a possible starting material we could use that we can convert into a ketone or an aldehyde if we wanted to.0533

    What are some of the reactions that we can have for carbonyls?--the majority of the reactions we are going to be seeing are going to be reactions with the carbonyl carbon.0542

    Which is always always always partially positive which makes it an electrophile; we are going to be reacting it with a variety of nucleophiles.0553

    One such nucleophile is hydride; we have seen lithium aluminum hydride as a source of H-.0561

    We can put that in quotes because that hydride is still attached to the aluminum; but it behaves as if it is an H-; so it is convenient to draw it that way.0569

    What reaction do you expect to have happen when hydride sees a carbonyl?--it is going to do the same thing that every nucleophile does.0580

    It is going to attack the carbon, then break the π bond, and move those electrons up onto oxygen.0588

    We will get an O-; we will have an H now bonded to the carbonyl carbon, the formally carbonyl carbon; that is what we get with hydride.0597

    Step two here, what is the purpose of step two?--step two is just our reaction workup; we do an acidic workup so that we can protonate anything that needs protonating.0607

    Of course it is the O- here that we want to protonate; we could just describe HA as coming in and providing a proton; the product we would get then is an alcohol.0616

    We could take a ketone or an aldehyde and we can convert it to an alcohol by hydride reaction; this is described as a reduction reaction; you could describe this as a hydride reduction.0631

    Because what we did was we decreased the number of C-O bonds and we increased the number of C-H bonds; that is the exact opposite of an oxidation reaction.0646

    Just a little reminder here that if we had a carbonyl, we can convert the carbonyl to an alcohol by a reduction reaction, a reducing agent.0660

    Something like LAH that we just saw, lithium aluminum hydride; we also know how to take the alcohol and oxidize it to the carbonyl by using something like PCC.0669

    Alcohols and carbonyls are very readily interconverted by functional group interconversions using either an oxidizing agent or a reducing agent.0679

    How about a carbon nucleophile, some sort of C-?--there is two kinds of carbon nucleophiles we can look at.0692

    One is just a straight out carbanion; what carbon can hold a negative charge and just be a salt with something like a sodium cation?0700

    There is really only a couple examples of this we have seen; we have seen acetylide anions; we have seen cyanide anions.0710

    What makes these special and unique and able to hold a negative charge is because they are sp hybridized; that triple bond allows us to simply deprotonate that carbon and use it as a nucleophile.0717

    For example, if we took acetylene and we react it with NaNH2; who is NaNH2?--that means we have Na+NH2-.0734

    NH2- looks to me like a very very strong base; what happens when a base sees a terminal alkyne or acetylene?--this is an acidic proton; we are going to deprotonate.0744

    Once again the reason I can deprotonate here is completely because it is an sp hybridized carbon; that is what stabilizes the negative charge.0765

    This is a reasonable nucleophile; what nucleophile can it react with?--that is what we are doing in step two is we are reacting with this electrophile.0774

    The nucleophile is going to see this electrophile; again carbonyl, partial positive, always an electrophile; what reaction happens?0785

    Our nucleophile, in this case our C- attacks the carbon, breaks the π bond, same thing every time when a nucleophile attacks.0794

    We will end up with an O-; now we have added a carbon-carbon triple bond here to that carbon.0804

    What do we need to do in step three?--step three, we need to have a workup so that we can protonate our O-; we get another alcohol product.0813

    When a nucleophile attacks a carbonyl, we will get this alcohol; but this is not a simple reduction reaction like we saw before because we are adding this carbon chain.0831

    What is new here is we have created a new carbon-carbon bond; that is a really big deal for synthesis; what is exciting about carbonyls is they are carbon electrophiles.0842

    If we combine it with a carbon nucleophile, we can create an alcohol with a new carbon-carbon bond that is being formed.0854

    Cyanide is another example of a carbanion that exists; we could just use that sodium cyanide anion; we can have as commercially available.0864

    Once again it is going to attack the carbonyl and break the π bond; what is going to happen after workup?0876

    We are going to have an OH where we used to have a carbonyl; now we are going to have a CN attached to the carbon.0883

    In each case, we are seeing... we saw hydride attacking the carbonyl; we can also have an acetylide type anion; or we can have a cyanide type anion; those are all good.0890

    These are called cyanohydrins--this structure where we have a CN and an OH on the same carbon.0900

    This is an interesting reaction because this is the only reaction we have seen so far that is reversible; in other words, this can kick back out that molecule of HCN.0905

    Because cyanide is poisonous, this is something that is dangerous; when we have a structure like this, we should know that that is something that could generate some cyanide.0919

    Another class of carbon nucleophiles are the organometallic reagents; what is great about organometallic reagents like a Grignard reagent or an organolithium reagent.0933

    Remember all of these are like having an R-; what is great about the organometallic is you can have any kind of R- that you can imagine.0943

    Unlike having to have a triple bond for a carbanion, with an organometallic you can have phenyl groups; you can have alkyl groups.0951

    You can have just about anything you can imagine, all sorts of different carbon chains.0959

    Let's look at an example of that; what would happen if I took this aldehyde and I react it with phenyl magnesium bromide.0964

    Phenyl magnesium bromide acts like it is a phenyl minus, great nucleophile; I know my carbonyl is a great electrophile.0971

    Let's see if we could predict the product here; I think that nucleophile is going to attack the carbon, break the π bond.0980

    We now have a phenyl group, a benzene ring; we could draw that out if you want or you could just keep it a Ph but just to remind what is happening here.0990

    We have just added a phenyl ring to this carbonyl carbon; then after workup, step two we are going to end up with an alcohol.1005

    Hopefully you are seeing a trend here that reaction of the carbonyl with a nucleophile is going to give some kind of alcohol product.1014

    Where this comes in handy is if we are given an alcohol as a target molecule, we can keep that in mind as we plan our synthesis.1027

    If we wanted to take a look at the retrosynthesis of this alcohol, retrosynthesis is asking what starting materials do I need?--what starting materials do I need to make this alcohol?1036

    What we just learned was that you can identify that carbon bearing the OH group and you can take any one of these other carbon groups and do a disconnection there.1048

    When I do that disconnection, I think about the two carbons that are coming together to form this new carbon-carbon bond.1061

    Then I ask myself which of those was a nucleophile, which of those was an electrophile, what did they look like as starting materials so that they could come together and make this product?1068

    The R group can be good as a nucleophile; something like a Grignard reagent would be a great way to make any carbon group nucleophilic.1080

    Which means this carbon was my electrophile; what did my electrophile look like?--what kind of electrophilic carbon can I have?1093

    That after a nucleophile attacks it, I am going to have an alcohol at that position?--of course it is the carbonyl.1102

    This guy was the carbonyl; I can draw this ketone for example and an appropriate Grignard... a Grignard.1110

    Let's check our work; if I had this ketone and I react it with this Grignard, after reaction workup, absolutely I would get this alcohol.1131

    That new carbon group would add in to the carbonyl; I would now have an OH at that position.1139

    This is a very nice strategy to keep in mind; if I want an alcohol, the way I make an alcohol is I work backwards to a ketone and a Grignard.1144

    It is good to keep in mind that a ketone plus a Grignard gives an alcohol; a ketone plus a Grignard gives an alcohol; a ketone plus a Grignard gives an alcohol.1156

    It is a great strategy to use anytime you need to do an alcohol synthesis; let's try and do an example; how about if you were given this transform problem.1166

    What are the reagents necessary to convert the given starting material into the desired product?--as usual more than one step might be necessary.1177

    The way that we need to approach these problems, the systematic approach we should have is we should look at the target molecule.1185

    Look at this product as a target molecule and do a retrosynthesis, ask what starting materials do I need?1191

    When I compare this alcohol to my starting carbon chain, I see that I started with this six carbon chain.1199

    But now I have this six carbon ring plus these extra three carbons; that directs me to where I need to do my disconnection.1205

    In other words, I know that in the course of this synthesis, I have to form this carbon-carbon bond; how do I do that?1211

    In order to do that, I look at these two carbons involved and I ask myself which one was my nucleophile, which one was my electrophile?1220

    I am going to come back to the carbon that now has the OH; which part was that carbon?--that carbon was the electrophile as a carbonyl; so this carbon was my nucleophile.1228

    How do I make an alcohol?--I have an alcohol target molecule; how do I make an alcohol?--from a ketone plus a Grignard.1243

    I am really asking what ketone and what Grignard do I need in order to make this alcohol?1253

    I need this three carbon carbonyl; I need acetone as my ketone, as my electrophile.1259

    What Grignard do I need?--I need this cyclohexyl Grignard, MgCl in this case; or remember I could do a lithium here too.1269

    When I say ketone, what I really mean is ketone or aldehyde, something like a ketone; when I say Grignard, that means Grignard; organolithium would do the same reaction.1280

    But ketone plus a Grignard gives an alcohol is a nice simple phrase to remember.1289

    If I had these two components as my electrophile and my nucleophile, they would be able to create the target molecule; that is awesome.1296

    How do I get to where I need to go from where I am?--right now, I am at chlorocyclohexane; can I go from chlorocyclohexane to cyclohexylmagnesium chloride?1304

    Of course, all I need to do is add in magnesium metal; I can make this Grignard reagent; once I have my Grignard reagent, I need to add in an appropriate electrophile.1318

    It is going to be acetone which is the ketone I need in this case; and I am on my way to the my alcohol.1328

    Is there anything missing in these reaction conditions?--would this second part work to give me my alcohol?--there is something that is missing.1335

    I could imagine this Grignard attacking the carbon and breaking the π bond; but that is going to give me an O-; how do I turn this into an OH?--I need to have an aqueous workup.1343

    Any Grignard reaction is always going to be a two-step process; first we react the Grignard with the electrophile.1353

    Then step two, we add in some H3O+; we do some kind of acidic workup.1359

    It is really important to show these numbers here, step one and step two, to show that these two are done in sequence, one after the other.1364

    And we can make this alcohol do this transform; here is another one; what if I had to start with this alcohol and make this new alcohol?1374

    Again I see that I can identify my carbon chain; I have one, two, three carbons here; one, two, three carbons; I clearly see that this is a new carbon-carbon bond that has to be formed in the reaction.1387

    If you didn't try and do this with retrosynthesis, you could fall into a trap; you could say I need to get rid of that hydrogen and I need to replace this with an ethyl group.1406

    Maybe I can react this with some really strong base like NaNH2; I have deprotonated hydrogens before with NaNH2.1421

    Then I can make this anion; then I could use that as my nucleophile and react it with something like ethyl iodide or bromide and do an Sn2.1432

    A lot of times when we just started our starting material and force our way through to the product, we come up with a problem like this; we make mistakes.1450

    This synthesis would never work as shown; what is the problem here?--what is the problem here?--first of all we are reacting with a strong base.1460

    Where do I have an acidic proton in this molecule?--do I have any acidic protons?--I do; it is up here; this is the only acidic proton.1468

    In fact this one is not acidic; even if I didn't have that OH, there is no way I can make this anion; this is completely an unstable anion.1477

    It would be impossible to make it; we can't just invent new reagents and new reactive species and intermediates that we have never seen before.1490

    When have we seen NaNH2 deprotonate a CH?--when is the only time we can do this?--only for alkynes; only if you have a CH on a triple bond, an sp hybridized carbon.1497

    That is the only time we are going to do this little trick and deprotonate and then maybe do an Sn2.1512

    This is a failed approach; the reason we fell into this trap is because we didn't do our systematic approach where we look at our product and think what do I need to make this product?1517

    The retrosynthesis is going to be a better approach; what starting materials do I need?--now I see the bond that I am breaking; I see the two carbons involved in the reaction.1529

    I ask how can they come together?--one of them must have been a nucleophile; one of them must have been an electrophile; which one was my electrophile?1540

    The carbon that is now a single bond O-H used to be the carbonyl; this was my carbonyl; this was my electrophile.1550

    That tells me that this carbon was my nucleophile; it had to be a nucleophile in order to react with it.1560

    I see that it is an alcohol; how do I make an alcohol?--how do I make an alcohol?--I make it from a ketone plus a Grignard.1567

    Who is my ketone?--I need this one, two, three carbon with a carbonyl; look it is acetone again; I need acetone.1579

    Then I need this two carbon group to be introduced as a Grignard, MgBr; or the organolithium would be fine here too.1587

    This is the planning that we need to do; we say if I had acetone in a reaction with ethyl magnesium bromide, I could make this product.1597

    Now I look back and see where I started; I am at isopropyl alcohol; I have isopropyl alcohol; I need acetone.1605

    Have I ever seen that synthesis before, that transformation before?--it looks like I am increasing my number of C-O bonds; what does that mean?1614

    It is an oxidation reaction; of course alcohols can be oxidized to ketones or aldehydes; we need an oxidizing agent; name an oxidizing agent.1625

    We have seen PCC; we have seen Jones; we have seen Swern; which of these would work?--all of them would be good; let's just pick one and go for it.1635

    PCC is usually my favorite because it is so short and easy to remember; and that works in all cases so PCC is good here.1642

    Then what did I want to do with this ketone once I made it? I wanted to react it with the Grignard; once again a two-step procedure.1649

    First I add in my Grignard reagent, MgBr; step two, I do aqueous workup, H3O+.1657

    As usual any synthesis problem, once you see it solved, it looks so simple; every step in a synthesis problem should be a simple ordinary reaction that you have seen a hundred times.1667

    But it is that combination of reactions and reagents and how you use them and what order you use them that make these multistep transformations possible.1679

    Without a systematic approach, without planning first, we can have some really disastrous consequences; it is really good to get into habit of doing this planning from the beginning.1689

    Let's take a look at one more example; this one is again going from one alcohol to another alcohol; I see we have a one, two, three carbon chain.1700

    It is not as obvious in this case where those three carbons are now; you might think this is one, two, three.1715

    But if I did that, now I would say here is my disconnection; somehow on carbon 1, I have to add this ethyl group; tell me what kind of reactivity carbon 1 has here.1724

    How would you get anything to happen with this carbon?--could it be a nucleophile?--could it be an electrophile?--nothing.1734

    There is a problem with this; let's redraw it and let's think of another way to identify those three carbons.1743

    What I am going to suggest is that carbon 1 started out as a methyl; it is a CH3; it is still going to be a methyl in the product.1750

    Where is carbon 1?--it is right here; one, two, three; there is my original carbon chain; there is my disconnection.1757

    I have an alcohol; I want to disconnect it; I think about my starting materials; I know that one approach is a ketone plus a Grignard; that has worked well for us so far.1766

    I look at these two carbons; I think who is going to be my nucleophile, who is going to be my electrophile?--we end up in a bit of a dilemma; we end up in a bit of a dilemma.1779

    This three-carbon chain, just my alkyl group, can be my Grignard; this guy was my nucleophile; but what was my electrophile?1791

    Could my electrophile be this two carbon electrophile, in other words, the aldehyde?--would these combine to give our target molecule?1804

    This carbon would attack and we would get a three carbon with an OH on the wrong carbon.1817

    Remember a disconnection we have seen before was always the alcohol carbon was our carbonyl; here it is not the alcohol carbon that we are asking to be the electrophile; it is the next carbon over.1827

    This approach isn't going to work in this case with this disconnection; let's come back and think about what starting materials we really had.1838

    Again I like the fact that this guy was my nucleophile; but here is the electrophile we need; let's just look at it as a synthon and say I need something that is electrophilic.1849

    I need to imagine an electrophile that is electrophilic not on the same carbon as the oxygen but the next carbon over.1862

    What electrophile have we seen before that the Grignard can be adding to?--how about if we add this lone pair back in, what electrophile would you end up with?1869

    How about an epoxide?--have we ever seen an epoxide as an electrophile, an epoxide being an electrophile?--of course.1882

    Ketone plus a Grignard is not the only way to make alcohols; it is just going to be the most common way we are going to see repeated throughout.1892

    But of course you can maybe have a disconnection at the next carbon over; you could do an epoxide ring opening to give that pattern.1900

    If I had this Grignard and this epoxide, yes they would combine to give the target molecule we are shooting for.1911

    Now I look back at where I am; I am at an alcohol; I need to turn this into a Grignard; where do Grignards come from?--let's keep doing our retrosynthesis.1917

    How would you make propyl magnesium bromide?--I would need a bromine in that position; I would need a halide of some kind in that position; then I could convert it to the Grignard.1926

    What I am going to need to do first is convert this to a bromide or a chloride or an iodide, your choice; what would be a good reagent to do that?1938

    Maybe PBr3 would be a good choice; there is no chance of rearranging; remember that makes a good leaving group and it displaces it with the bromine.1949

    Now we have our alkyl halide; what did we want to do with that?--we wanted to make that the Grignard reagent.1960

    We just add in some magnesium metal; now we have the Grignard; that is our nucleophile; what do we do with that nucleophile?1964

    What electrophile do we need?--we wanted this epoxide; this is called ethylene oxide; this will bring us to our target molecule by reacting with ethylene oxide.1973

    As usual with our Grignard, it is going to be two steps; first step one is react it with the epoxide; step two is do H3O+ workup.1984

    Synthesis of alcohols requires identifying the disconnection; then looking at the two carbons involved and saying who would be a nucleophile, who would be a good electrophile?1994

    As always, we want to work back to starting materials and reagents that are recognizable, that are simple, that are things we have seen before, we have used before.2005

    So we know the synthesis is going to work once we put it all together; here is one more.2012

    I am starting out with the phenyl and this carbonyl; I still have the phenyl and this carbon; now I have two carbon groups that I need to add in.2022

    This is going to be a little more challenging; we can start with either one of them; let's start with this disconnection here.2033

    These are the two carbons that we want to come together; this is an alcohol; let's try to go back to a ketone plus a Grignard.2042

    The carbon that now has the OH was my carbonyl; I need this ketone; my Grignard in this case was the three carbon chain; there is my electrophile; there is my nucleophile.2056

    I need to have this ketone and this Grignard if I want to make the target molecule; that is good.2073

    But now I compare my aldehyde and my ketone and say how do I get from an aldehyde to a ketone?2080

    Can I deprotonate this CH with a strong base and add in that alkyl group?--could I deprotonate here??no.2092

    When we are trying to take that approach, again we are grasping at things because we don't know how to get there.2102

    We have to think about the reactivity of this carbon; carbon 2 is a carbonyl carbon; it is an electrophile.2109

    How are we going to add in this isopropyl group?--we are going to add it as a nucleophile.2117

    Let me show this is a nice example because after working backwards a little bit, maybe we get stuck.2123

    Let's go ahead and start working forwards a little bit and see if we could bridge the gap in between.2129

    If I wanted to add this isopropryl group, how do I make it nucleophilic?--I just add on a metal, magnesium bromide or lithium.2136

    Step one, magnesium; step two, H3O+; I would be able to add one of my carbon groups; this clearly is moving me towards my target molecule.2144

    The question is how do I add the second carbon group?--can I just add in my second Grignard?--is that going to add in the second one?--do alcohols react with Grignards?2156

    In fact they do; they don't do it to form a carbon-carbon bond; this simply acts as an acid and the Grignard acts as a strong base; in fact you would just deprotonate.2171

    That is not what we want to do; this is where our planning came in; when can we use this propyl Grignard?--when we have a carbonyl to react it with; we don't have a carbonyl; we need a carbonyl.2181

    If I had this carbonyl, now I could see where I can go with it; I could add in my Grignard; how do I go from an alcohol to a carbonyl?--this is an oxidation; all we need is PCC.2197

    We can get to our carbonyl; now we are ready to add in our second equivalent of the Grignard or our second type of Grignard, H3O+, and it works.2210

    In this case because I had to add two carbon nucleophiles to my carbonyl carbon, the strategy was to add the first carbon nucleophile to give me an alcohol product.2223

    Then I had to reoxidize to a new carbonyl so that I could add a second equivalent of the Grignard, a second nucleophile, to add the second carbon group.2235

    I like this example because sometimes when you are doing your retrosynthesis, if you get stuck, just trying working forwards a little bit.2245

    When we go in both directions, hopefully that will get us through the entire synthesis.2253

    Another interesting reaction we can have for carbonyls is a very special kind of nucleophile called a Wittig reagent; this undergoes what is known as a Wittig reaction.2261

    Notice it is spelled with a ?w but it is pronounced with a ?v; it is a German word, German name.2273

    A Wittig reagent is an example... there is a typo... of resonance stabilized carbanion; it looks like this; it has a P+ attached to a C-; this is called an ylide.2281

    An ylide means that you mean have a + and a ? charge in the same structure; it is called a phosphonium ylide because that is what we call a P+; phosphonium ylide.2294

    This has resonance stabilization; there is this second resonance form we could draw for this; that is taking this lone pair and bringing it in as a π bond.2306

    This is another way that we can draw it; the Wittig reagent is something we can draw either way; we should get used to seeing it either way.2318

    Sometimes it is just drawn as a phosphorus carbon double bond; sometimes it is drawn with a P+ and C-.2324

    It doesn't matter which way we draw it; it is the same thing; we are going to see what it does.2330

    But this resonance stabilized which is why it is okay to have this C-; ordinarily we don't want to have a negative charge on a carbon; but this is a possibility; this one is okay.2334

    What are we going to do with it?--when we see a Wittig reagent like this and we react it with either a ketone or an aldehyde.2346

    What we are going to do is we are going to identify the carbon group that is attached to the phosphorus; we are going to replace the oxygen of the carbonyl with that carbon group.2353

    Where we used to have a C-O double bond, we are now going to have a C-C double bond; here it was a CH2; so now it is going to be a CH2.2364

    The Wittig reaction turns a ketone or an aldehyde into an alkene; this is an excellent method for synthesizing alkenes from ketones and aldehydes.2375

    Let's take a brief look at the mechanism; the mechanism is a little strange compared to some we have seen before.2392

    But I do want you to see how it is not just magical where this carbon-carbon double bond comes from.2396

    The reaction starts out simple enough because when we look at this resonance form of the Wittig reagent and we see the C-, we see how it is clearly a nucleophile.2403

    We have a C-; our carbonyl we know is an electrophile; what is going to happen first?2413

    Same thing that always happens; our nucleophile attacks the carbonyl, breaks the π bond; this now gives us an O-; attached we have the carbon group plus this triphenylphosphine group.2418

    Because we have a P+ and an O- that are close to each other, what happens is the oxygen then bonds to the phosphorus to make this four-membered ring.2434

    It is called an oxaphosphetane; we get this oxaphosphetane intermediate; very rare to see a four-membered ring; I know that; but phosphorus on the periodic table is below nitrogen.2444

    Phosphorus is bigger; it has bigger arms; that four-membered ring is not nearly as strained as we would associate with a carbon or an oxygen type ring.2455

    This is not our final product; this falls apart; this falls apart by undergoing a pericyclic reaction.2467

    What happens is this bond breaks and becomes a π bond; and this bond breaks and becomes a π bond; these four electrons and these two arrows all rearrange at once.2478

    What we form then is a... this is where we get our π bond for our carbon-carbon double bond; what else is formed in this reaction?2491

    We get a phosphorus with three phenyl groups on it and a P-O double bond; we get this triphenylphosphine oxide as a byproduct of our Wittig.2499

    This is something that we can separate, we could filter off; we are left with an alkene product.2512

    Where does the Wittig reagent come from?--it is going to be two steps to prepare this; it comes from an alkyl halide.2519

    For example, if we wanted to make... let's redraw the Wittig reagent we just used on the previous slide.2526

    If I wanted to make this Wittig reagent which has just one carbon on it, the way I would start is I would start with the one carbon alkyl halide.2531

    Obviously I need to introduce this triphenylphosphino group; that is what I used; this is called triphenylphosphine; triphenylphosphine, awesome nucleophile.2542

    Again phosphorus is right underneath nitrogen; we know nitrogen is a very good nucleophile, loves to do the Sn2.2554

    Phosphorus, because it is even bigger, more polarizable, it is an excellent excellent nucleophile.2560

    When it sees an alkyl halide, it very readily will do an Sn2 mechanism, backside attach, and form this carbon-phosphorus bond.2566

    Phosphorus now has four bonds; we count one, two, three, four; just like nitrogen, phosphorus wants five; it is missing an electron; that is why we have a P+.2578

    That is our first part; let me draw this in the other resonance form also so we can think about...2592

    It is always nice to consider where we are heading when we are considering a mechanism or a synthesis on how to get there.2602

    We have introduced this P+ part; what we now need is the C- part; we started with a CH3; now we want it to be a CH2.2609

    What has happened here?--it looks like we have done a deprotonation; we need to deprotonate; the reagent we need for that is a very strong base.2619

    The base that we typically use in the Wittig reagent is butyllithium, extremely strong base; where have we seen butyllithium before or any organic lithium?2630

    We have seen it as an organometallic reagent just like a Grignard; this would be an incredibly strong base; it is just like any organolithium we have seen or like a Grignard reagent.2643

    This is one that is just pretty available, commercially available; so it is an excellent strong base to use anytime we need it.2657

    What we are going to do is we are going to grab one of these protons; let's just make this a CH2; we could see one of these protons and our butyl minus that we have.2664

    Of course we are going to put that in quotes because it is not really butyl minus; it still has the metal attached; but it acts like butyl minus as a base.2675

    It is going to grab that proton and either put those electrons right on the carbon so we have a P+C-.2681

    Or you could draw the other resonance form where it brings the two electrons in as a π bond; either way we now have the Wittig reagent.2687

    We got there in two steps--Sn2 with triphenylphosphine and then strong base to deprotonate that carbon.2695

    Let's try a predict-the-product for a Wittig reaction; we are starting with an aldehyde or a ketone; this is the substrate for a Wittig reaction.2703

    Here is our Wittig reagent; I see we have a P+ and a C-; how do we predict the product of a Wittig?2714

    Very very simple; I know the mechanism is a little scary, but predicting the product is very simple.2723

    We find the carbon group of the Wittig reagent; it is whatever group is attached to the phosphorus; we replace the oxygen on the carbonyl with that group.2729

    We replace our C-O double bond with a C-C double bond; what did this have?--this had three carbons; we are going to add three carbons.2741

    That is a nice way to check that you have done the Wittig reaction; this started with three carbons; we are adding a three carbon aldehyde and a three carbon Wittig.2753

    We need to have a six carbon product; that is a good way to make sure you haven't lost any carbons; maybe if you are doing a line drawing, you might come up with that a little bit.2761

    So we are going to get an alkene product; the Wittig reaction is a great way to make alkenes.2773

    Knowing that, if we ever have an alkene as a target molecule, one way we can make this is by doing a Wittig reaction.2782

    The Wittig disconnection is completely breaking through the carbon-carbon double bond because in the Wittig reaction, both of those two bonds are formed during the course of the mechanism.2790

    What it will do is it will completely cleave it; one of these carbons was the nucleophile; one was the electrophile; because it is an alkene, you can pick either one.2803

    Typically the one that is a little less hindered would be the better electrophile; we could put the carbonyl in the less hindered position.2815

    In other words, an aldehyde would be better than a ketone for the Wittig, a little faster; but both would be okay.2826

    Which means this guy was my nucleophile; how do you make it a nucleophile?--it is going to be a Wittig reagent.2831

    One possible disconnection for an alkene is to work backwards to a suitable Wittig reagent; what does this Wittig reagent look like?2840

    It is this six-membered ring with the PPh3 attached with the double bond; or you could draw the C-P+, same thing.2849

    This is our Wittig reagent; that is our nucleophile; what is the electrophile?--we had this two carbon carbonyl; that is just an aldehyde; it is acetaldehyde.2858

    Typically when we draw aldehydes, we usually draw in that CH in the line drawing; it is acceptable to leave it off; but convention usually puts it in there; we will add that in there for clarity.2872

    In this case, it is an aldehyde; that is going to be our electrophile; this is the Wittig reagent we need; let's see if we could do a synthesis of this.2885

    You may be given instructions where you could just use a Wittig reagent and assume it is commercially available.2897

    But if you had instructions... let's say you had instructions where the starting materials had to be alcohol starting materials only; for example; that makes the problem a little more challenging.2902

    In other words, now you have to make this Wittig reagent starting from an alcohol; you have to make this aldehyde starting from an alcohol.2917

    Let's think then about this Wittig reagent; where do Wittig reagents come from?--we saw that it is a two-step synthesis; it comes from an alkyl halide in that position.2925

    We need a halogen in that position--chloride, bromide, iodide, your choice, whichever one you want.2936

    I need cyclohexyl bromide; but I have to start with cyclohexyl alcohol; how could I convert that to the bromide?--there is a variety of reagents; I could use PBr3.2946

    Or in this case because there is no possible rearrangements to give any other product, I could maybe use something like HBr; that would work well to give this bromide.2963

    A few possibilities here; those would both be good; then how do I go from the bromide to the Wittig reagent?--how do I get this double bond PPh3?2972

    Remember there is going to be two steps; we can do them both over one arrow; the first step would be to introduce the phosphorus as triphenylphosphine--great nucleophile; that does the Sn2.2985

    Then the second step is to add a strong base, something like butyl lithium, to do a deprotonation; those are two-step procedure to make the Wittig.2997

    Then we want to add this aldehyde; where does the aldehyde come from?--if we had to have an alcohol starting material, we could start with the two carbonyl alcohol, ethanol.3006

    How could I go from an alcohol to an aldehyde?--that looks like an oxidation reaction; I know how to do that; we have PCC, Swern, and Jones; are all three of those okay here?3017

    Remember because this is a primary alcohol, this is the case where if we use something like Jones conditions, sodium dichromate and acid, chromic acid oxidation.3033

    This would over oxidize and give me the acid; in fact I want to use either PCC or Swern to do this.3044

    Now I have my aldehyde; now I have my Wittig reagent; I mix those together and I have my target molecule.3051

    Now that we know about the Wittig reaction, this is going to be one additional way that we can do a disconnection for a target molecule.3058

    It turns out that this synthesis is often much more reliable then forming an alkene by dehydration or by elimination reaction; so the Wittig reaction is very widely used in synthesis of alkenes.3066

    Everything we have seen up to now of reactions of aldehydes and ketones have been carbon nucleophiles; well, we saw the hydride nucleophile.3083

    But we also saw carbon nucleophiles--the acetylide or cyanide or a Grignard or the Wittig, forming new carbon-carbon bonds.3089

    We are going to shift gears now and take a look at reactions with oxygen nucleophiles; what is interesting about oxygen nucleophiles is right here--we see that this is reversible.3099

    The other reactions we saw, I know the cyanohydrin was one exception for that, but hydride and Grignard and Wittig, these are all reactions...3113

    Once you form a carbon-carbon bond, you don't go back from there; you don't break that carbon-carbon bond.3121

    But the oxygen nucleophiles are going to be something that you can form the C-O bond and it is going to be possible to break that C-O bond.3126

    The first oxygen nucleophile we will consider is addition of water; when we do that, the product we get is called a hydrate; as usual, this carbonyl is going to be my electrophile.3133

    If water was my nucleophile; if we just think about the pattern we have seen up till now, what does the product look like after a nucleophile attacks the carbonyl?3144

    We know that we end up with an OH where the carbonyl used to be; if water was my nucleophile, what do we end up with here?--we end up with another OH.3154

    What we have done is we have added water to the carbonyl; the oxygen is the nucleophile and then we protonate the original oxygen.3168

    This structure is called a hydrate; it is called the hydrate of an aldehyde or a ketone because we have literally added water to it.3178

    It turns out that this is a pretty unstable arrangement of functional groups; a carbon does not want to have two separate CO bonds and two OHs attached to it; this is extremely unstable.3188

    In fact because it is reversible, it turns out that the reverse reaction is favored; anytime you have this arrangement, it would rather rearrange and do a mechanism to get back to the carbonyl.3201

    This is more stable as the carbonyl; can you think of why that is that we would want to have this carbonyl instead of the two separate C-O bonds?3210

    Remember we started talking about how stable the carbonyl functional group is, how energetically favorable it is; this has resonance; we don't want to give that up to form this product.3224

    Although ketones and aldehydes can react with water, as a nucleophile, it is very rarely a favorable reaction; so I am not going to spend much time about it.3239

    There are a few exceptions though where the hydrate is in fact formed to a significant amount; one such example of that is formaldehyde.3251

    The very unique example of an aldehyde is when we have two hydrogens attached to the carbonyl; that is called formaldehyde; it turns out that this is very reactive; it is extremely reactive.3263

    We have just these hydrogens here; compared to a ketone that has carbon groups, alkyl groups, that can donate electron density, this is a great electrophile.3279

    It is very reactive; it is a huge partial plus; it has no steric crowding of any kind because we have just hydrogens here.3291

    That makes it really susceptible to nucleophilic attack; if you put it in a solution like even a water solution where water is around, water will attack it.3299

    It turns out that in an aqueous solution, you have the vast majority, 99 percent of the structure looks like this instead of the carbonyl.3308

    Because this carbonyl is really quite reactive; but any other aldehyde and any other ketone, we have the opposite; it would prefer to be a carbonyl.3318

    Another interesting example is that the hydrogen is going to be favored when you have a significant partial positive right next to the carbonyl.3328

    This is an interesting molecule; it is known as chloral; we know that the carbonyl carbon is partial positive.3339

    It has a significant partial positive because of the resonance contributor that puts a positive charge on the carbon.3347

    If on the α carbon, meaning the next carbon over, I put three chlorines, I know each of those chlorines is electronegative; those chlorines pull electron density away from this carbon.3354

    It turns out that this α carbon is also significantly partial positive; this is going to be something that destabilizes this molecule; the adjacent partial positive destabilizes the molecule.3365

    What is going to happen is again when you put this in water, we are now going to get formation of the hydrate; instead of a carbonyl, we have two OH groups.3385

    This now is going to be favored in the forward direction because you have less of a partial positive when you have the two separate OHs.3396

    This carbon is now less of a partial positive so we don't have those extremely electron deficient carbons right next to each other.3411

    This would be something that in this rare case, rather than have the carbonyl, we would rather have two separate OH groups.3418

    This molecule is called chloral hydrate; it is something that can be isolated because it is reasonably stable.3427

    This has an interesting history; if you have ever heard of Mickey Finn knockout drops or watched an old movie where they suggest that they slipped him a Mickey.3432

    This is the molecule that used for that--chloral hydrate; it can give off chloroform which acts as an anesthetic; this is something that can be used to render a person unconscious.3444

    A chloral hydrate is an example of one of those unique molecules where we would prefer to have the OHs.3457

    The other oxygen nucleophile we are going to consider is if we have an alcohol reacting with a carbonyl; this is a reaction that can be driven in the forward direction and can be quite useful.3467

    When we react an alcohol with a carbonyl, a ketone or an aldehyde, the product we are going to get is known as an acetal.3480

    Let's take a look at this reaction; if we take a ketone, this is our electrophile; we react it with an alcohol as a nucleophile, here is our alcohol, in the presence of TsOH.3487

    This is tosic acid; you could just say HA here; it doesn't have to be tosic acid; but you do need an acid catalyst.3500

    Tosic acid is a nice choice; that stands for toluene sulfonic acid; it looks a little like tosyl chloride, the reagent we have used before.3509

    If we have the tosyl with an OH group here, this is extremely acidic; in fact this structure looks a lot like sulfuric acid.3517

    Sulfuric acid has these two SO double bonds; it has an OH here and another OH here; we know sulfuric acid is a very strong acid; for the same reason, tosic acid is a very strong acid.3525

    But by adding in this aromatic ring, it makes it soluble in organic solvents; it makes it more nonpolar; so this is a nice acid to use when we are using organic solvents.3536

    What happens... let's imagine what can happen; what product would you get if alcohol was your nucleophile?3551

    We would end up adding an OR group to the carbonyl carbon; where we used to have a carbonyl, we would get an OH; this structure is in fact what is formed.3559

    However this is just an intermediate structure; the reaction doesn't stop here because the second equivalent of alcohol is going to come in and react.3571

    What will happen is we will end up replacing the carbonyl oxygen with two separate C-O bonds, both of them being OR groups.3580

    When you have one carbon with two OR groups attached, it is no longer called an ether; an ether would be if we had just one OR group.3590

    But this one carbon with two OR groups is described as an acetal; this functional group is called an acetal.3599

    For that reason, this structure here where you are just half way towards the acetal is called a hemiacetal, just like a hemisphere is half of the globe.3608

    Because you have just one OR group, we call this a hemiacetal; this is not stable; it will continue until we get the full acetal.3622

    We just talked about for the hydrate how we would rather have a carbonyl than two separate C-O bonds; why is it possible in this case to get the two separate C-O bonds?3630

    You are right; it is not something that is going to happen spontaneously and just on its own; the other product in this reaction, what is missing here?3641

    We lost this oxygen; plus we have the hydrogen from this alcohol and the hydrogen from this alcohol; the other product is going to be water that is formed in this reaction.3651

    The way we push this acetal formation reaction forward is we have to remove the water as it is formed, must be removed to push the equilibrium forward.3661

    That is because every step along this mechanism is reversible; every step we do can be undone.3677

    The only way to push it in one direction or the other is by removing one of the products as it is formed, Le Chatelier's Principle; we are just going to keep going forward to replace that.3684

    And if water is not here, we can't do the reverse reaction; so it stops the reverse reaction and promotes the forward reaction.3695

    First let's take a look at an example of this reaction and see if we could predict the product; then we will explore the mechanism.3705

    What if we took this aldehyde and we reacted it with methanol and tosic acid?--methanol and tosic acid.3711

    What is going to happen is we are going to replace our C-O double bond with two separate C-O bonds; the group that is going to be added is whatever OR group we have in our alcohol.3719

    Because it is methanol, we are going to add a methoxy group on one side and a methoxy group on the other side; we are going to go from an aldehyde to an acetal.3736

    We could always assume that we have an excess of our reagents; in fact in this reaction what you would do is you would use the alcohol typically as the solvent.3748

    You have a huge excess of that nucleophile; we assume that we are going to be able to go completely to the acetal because we have enough equivalents.3755

    We need the two equivalents; we will have them both here; of course our other product is water; if you want to balance your reaction and have everything there.3764

    Although typically a lot of times, predict-the-product, we are just looking for the organic product, what is the fate of this organic starting material.3773

    Let's use this example and let's think about the mechanism; how is it that we go from this aldehyde to this acetal?--let's think a little bit about the mechanism before we get started with it.3781

    I notice that they are acidic conditions because I see tosic acid; in fact this is always going to be true; acetal formation always requires an acid; what do you think the first step is going to be?3793

    If you see there is an acid present, what do acids do?--they donate a proton; they are going to protonate something; first step is protonate, always.3804

    When you have an acid around, strong acid around, you are going to find something to protonate; that is what is going to get the reaction going.3816

    Another thing to keep in mind, we have seen acid catalyzed or acidic condition mechanisms in the past.3822

    What was always true was for the charges in that reaction, all of our species are going to be either neutral or they are going to have a + charge.3828

    We are not going to have any strongly basic species like hydroxide or alkoxide; we can't have either of those in acidic conditions.3837

    We will keep that in mind too when we are doing our mechanism; let's take a look at that.3846

    The mechanism for acetal formation is going to start... because we have our acid, is going to start with a protonation step.3852

    Where could we protonate?--we have a couple oxygens here; we can protonate the alcohol; that will happen.3861

    But the protonation that is going to get our mechanism started is instead when we protonate the carbonyl oxygen; we will do that instead.3868

    Remember our mechanism we want to move us in the forward direction; we are going to protonate in the place that we need to; that is up here.3880

    Every step of this mechanism is going to be reversible; we want to make sure that we draw this as an equilibrium as we go from one step to the next.3888

    Protonate the carbonyl, what does that do for us?--why is that a good first step?--we know that a carbonyl... what kind of reactivity does a carbonyl have?3897

    Is it acid, base, electrophile, nucleophile?--it is an electrophile; every carbonyl is an electrophile because it is partially positive on the carbonyl carbon.3908

    What do you think is going to happen once we protonate that carbonyl?--now this carbonyl is positively charged; is that good for being an electrophile?3917

    Sure, an electrophile is supposed to be electron deficient; this is even more electron deficient now; it is actually has a positive charge; this is a great electrophile.3926

    When we see a species like this, we want to think about looking around for a nucleophile and having it attack; what nucleophile do we have?3934

    Our reaction is done in methanol; we have methanol as our solvent; that is most certainly going to be our nucleophile.3943

    What happens when the nucleophile sees a carbonyl?--it attacks the carbonyl, breaks the π bond.3950

    This top oxygen now is back to being a neutral oxygen--two bonds, two lone pairs; tell me about this oxygen; what does that have attached to it?--it still has the CH3 and the hydrogen.3963

    Does it have any lone pairs?--it used to have two; but these two electrons are now in this bond, being shared as a bond; it just has one lone pair left; this now looks like it is not a neutral oxygen.3979

    Let's check; one, two, three, four, five; oxygen has five but it wants six; this is missing an electron; it is positively charged.3993

    I know my mechanism isn't done here; I need to get rid of that positive charge; how can I do that?4005

    I can get rid of this proton because I need to have only two bonds to oxygen; if I get rid of this proton, what I can use is I can use my A- that I formed in my first step to come grab that proton.4011

    Or I can use my methanol to come in and grab that proton; both of those are reasonable; methanol is probably our better choice since that is our solvent; we have more of that.4023

    This has some nice bookkeeping; we can attack the proton and leave the electrons on the oxygen.4033

    Let's take a look at what we have accomplished so far; what mechanism did we have?--we protonate, then we attack, then we deprotonate.4043

    Protonate, attack, deprotonate; have we seen that pattern before?--absolutely; this is a very common pattern that we have for acid catalyzed reactions.4059

    Have we gotten closer to our product?--we have; we know that eventually we got rid of the carbonyl; we know eventually we have to get two methoxy groups here.4069

    We have installed one of them; we have an OCH3 and we have an OH on the same carbon.4079

    What functional group have we just converted the aldehyde into?--when we have an OR and an OH, we call this a hemiacetal.4085

    You know you are going in the right direction in acetal formation, this is an acetal, when the first thing you should be doing is making the hemacetal.4094

    Now we need to again thinking about where we are going, we need to get rid of this OH and replace it with an OCH3; that is where we are headed; how can we do it?4104

    What can we do to move that substitution in the right direction?--how about if we protonate the OH as our next step?--that is not a bad idea too because remember we are in acidic conditions.4114

    If we are stuck somewhere, we have a neutral compound; let's find a place to protonate to get us going again.4128

    What does that do for us?--why would that maybe move us in a forward direction?--by protonating the OH, it gives us a very good leaving group.4138

    We turn this into a great leaving group; if we want to do a substitution and get rid of that group, this would be ideal for that.4151

    Now here is the question: how does this leaving group leave?--we have seen substitution mechanisms before.4159

    We have seen Sn2 mechanisms, backside attack, where our nucleophile comes in in a single step, kicks out a leaving group.4165

    We have seen Sn1 mechanisms where a leaving group just leaves on its own and then a nucleophile comes in.4173

    Neither of those... those mechanisms are for tetrahedral carbons bearing the leaving group like an alkyl halide.4179

    Neither of those examples are going to accurately describe carbonyl chemistry which is what we are dealing with in this unit.4186

    Instead the way we are going to describe this substitution is this intermediate is called the CTI.4193

    That stands for a charged tetrahedral intermediate; we are going to look more closely into that definition on the next slide.4204

    But what we have essentially is on the same we have a leaving group and we have a group that can help push that leaving group out.4213

    What happens with CTIs is they collapse; the collapse of a CTI looks like this; the leaving group leaves; but it doesn't just leave on its own; it leaves with the assistance of that second group.4222

    We use these two arrows to help push the leaving group out; let's see where that brings us; when we follow those electrons around, we end up with this structure.4237

    What did we just kick out?--we just kicked out our molecule of water; we know that we form water in this product.4254

    We know that that water must be removed in order to push the equilibrium forward; this is the point at which the water is removed; the reverse reaction can no longer happen.4263

    Let's take a look at this structure; something is missing on this structure; I had a positive charge and I lost a neutral molecule; there still must be a positive charge somewhere.4274

    Where is it?--yes, this oxygen has one, two, three, four, five; oxygen wants six; this is a O+.4283

    Still we are moving in the right directions; we have gotten rid of that oxygen that we needed to replace, that OH group; where do we go from here?--what does this structure look like?4292

    Do you think it is going to be a good nucleophile, electrophile?--it has a positive charge; it has a carbonyl with a positive charge; have we ever seen a species like that?4301

    Yes, right here; right here; what did we say about this type of carbonyl with a positive charge?--it is a great electrophile; it is a great electrophile.4310

    What do we do next?--we look around for a nucleophile; this is how our second equivalent of the alcohol comes back in, as our nucleophile.4320

    What mechanism can you imagine happening?--it attacks the carbon, breaks the π bond.4331

    Now we have at this bottom carbon, we are back to just a nice neutral methoxy group, OCH3; what do we have on this top carbon?4343

    Because methanol attacked, we have a hydrogen; we have a methyl is still there; one lone pair and positive charge.4353

    How close are we to our acetal product that we have?--how close are we?--we just have one proton left that we need to get rid of; that will give us our acetal and get rid of our positive charge.4364

    Our final step in this mechanism is going to be deprotonation; again I can use my A- to come in and deprotonate.4378

    Look at what we made; we converted the carbonyl, the C-O double bond, into two methoxy groups, two methoxy groups.4396

    Remember what we pointed out, what we just thought about on the previous slide; we said our first step is going to be protonate because we are in acid.4408

    We said all of our species should have positive charges or should be neutral; take a look; there were no negative charges here.4417

    It might be tempting sometimes to use methoxide as our nucleophile; that would be a quick way to put in a methoxy group.4425

    But there is no methoxide in strongly acidic conditions; instead methanol is the nucleophile we have to use.4434

    Note the charges; no HO- or RO-; the other thing to note is that it is catalytic; it is catalytic in acid.4441

    That means for every step where I use an acid and protonate, there is another step somewhere where I deprotonate and get that acid back.4455

    I used HA; then I reformed HA; here is another step; I used HA here, I protonated; but then at the end, I deprotonated and got that HA back.4465

    To form an acetal, you take an aldehyde or a ketone, dissolve it in an alcohol with just a trace amount of acid, just a catalytic amount of acid; we will form acetal.4476

    Next let's take a little closer look at what describes a CTI because we are going to see these mechanisms again and again when we are looking at carbonyl mechanisms.4489

    What does it mean to be a charged tetrahedral intermediate?--the first thing that we are going to start with is something called a tetrahedral intermediate.4499

    Tetrahedral means that we have an sp3 hybridized carbon; that means there is just four single bonds to that carbon; at least two of those groups have lone pairs.4512

    We have a situation like this where attached to a carbon, we have two separate groups that have lone pairs, at least two.4521

    It turns out that this arrangement can be unstable; this is inherently unstable; we saw that when you have an OH and an OH, that structure is not so good.4529

    When you have an OR and an OR that structure is something that can react and can be undone.4539

    The way it becomes unstable is when it becomes a charged tetrahedral intermediate; this is what CTI stands for.4546

    It is when you have this same situation, tetrahedral carbon with two groups with lone pairs; but now one of the group has a charge.4555

    When you have this then you get an intermediate; you get a structure that can collapse.4564

    We are going to encounter CTIs in acidic conditions and in basic conditions; of course in this unit, acetal formation is always acidic.4571

    We are going to get something like this; we are going to get a CTI where we have one group with lone pairs and another group with a positive charge.4578

    What we just did let's say is protonate with our acid; that makes this a very good leaving group.4588

    What happens is that leaving group will leave; collapse of a CTI means the leaving group leaves; but it does so with assistance from that lone pair.4594

    It can collapse; we have two arrows; we describe this as a push-pull relationship going on; the leaving group is pulling as usual and doing its leaving group thing.4604

    But you have someone pushing them out at the same time; this makes it a very favorable reaction.4616

    In a base catalyzed situation, our CTI is going to have a negative charge; that is going to make the group that is doing the pushing real good; that makes the other group our leaving group.4622

    Same two arrows; in this case, the group with the negative charge does the pushing and the neutral group is what gets kicked out; so two arrows to collapse a CTI; then we go from there.4636

    The key is when you see a CTI, when you see a charged tetrahedral intermediate, by recognizing that as such, it is going to help guide you in your mechanism.4653

    Because you know what a possible thing that it can do--is it could collapse and kick out one of the groups and go from there.4662

    Let's summarize what we have seen for acetals; if we take a carbonyl and we treat it with an alcohol and some acid like tosic acid; we replace that carbonyl with two OR groups.4671

    In other words, it adds two equivalents of ROH, two equivalents of the alcohol.4683

    It turns out that if you take an acetal and you treat it with water, H3O+, if you treat it with water and acid, the reverse reaction can take place.4695

    We could have a ketone or an aldehyde here; we go to an acetal; if we have an acetal and we treat it with water and acid, it can go back to the carbonyl and kick out your molecules of alcohol.4710

    It is also possible to make a cyclic acetal; the way we get that is we use this; when you take a look at this structure, it contains both equivalents of OH; it is a diol.4727

    If I use a diol rather than a regular alcohol, what can happen is that one molecule can deliver both equivalents of the oxygen.4747

    The structure we are going to end up then has those two oxygens still tethered together; we are going to get a cyclic acetal.4755

    Mechanism for that formation?--exact same mechanism we just saw for the acetal formation.4765

    Except when the second equivalent of oxygen comes in, it is not a separate molecule, a separate alcohol coming in and attacking.4771

    It is going to be an intramolecular attack of the oxygen that is already tethered to the molecule; so we can also make cyclic acetals.4779

    Just like any acetal, reaction of this with H3O+ would regenerate the carbonyl and get rid of that alcohol molecule; in this case, a diol molecule.4788

    Let's take a look at that reverse process; we call that hydrolysis of acetals, reaction of an acetal with H3O+; this is something that regenerates the carbonyl.4803

    If I take an acetal; how do I know this is an acetal?--what does it mean to be an acetal?--we have one carbon with two separate OR groups attached.4813

    When I have this and I treat it with H3O+, that means we have water and we have some strong acid.4825

    You can either see it written as H3O+ or you might see it written as H2O, H2SO4, something like that.4832

    When that happens, we take that carbon with the two separate OR groups and we bring it back to being a carbonyl where both oxygen bonds are going to the same oxygen.4839

    What else do we form here?--these two molecules of methanol are going to come back out; we are doing the reverse of that acetal formation; we call this hydrolysis.4855

    Just a quick question: is this an oxidation?--anytime we have seen a reaction that forms a carbonyl like this before, we described it as an oxidation.4869

    Would this mechanism be described as an oxidation?--why or why not?--what do we expect in an oxidation reaction?--we expect to increase our number of C-O bonds.4887

    How many do we start with?--we started with two C-O bonds; now we have still two C-O bonds; no, because we have two C-O bonds at the beginning and at the ending.4897

    We don't use an oxidizing agent; we are just using water; this is hydrolysis; this is reaction of water; we are trading one C-O bond for a different C-O bond.4912

    It is going to be again characteristic of reactions that we described as hydrolysis down the line; so it is good to think of that term.4922

    Let's see if we could do the mechanism; it turns out that the mechanism is the exact opposite of the acetal formation.4929

    However many steps our acetal formation was, we are going to have that exact same number of steps for the hydrolysis.4939

    In fact every structure along the way that we saw in the forward direction, we are going to go through those exact same structures as we move back to the carbonyl.4946

    We have our acetal; we are treating it with H3O+; think about what you would do first.4956

    How do you get started here?--we have acid; anytime we have acid, we are going to protonate first; we always know how to get started.4965

    Where could we protonate?--it must be one of these oxygens on the acetal; we could just say HA if you want for H3O+; that is fine.4977

    Remember this step though is reversible; we could protonate; we could deprotonate; we could protonate, deprotonate; let's see what happens when we protonate one of those methoxy groups.4988

    What does that do for us?--where do we go from here?--this is a pretty interesting intermediate; it is an interesting intermediate because we have a group with a positive charge.5006

    And on that same carbon, we have another group with lone pairs; we have a name for this; it is some kind of charged tetrahedral intermediate; yes, there it is; this is a CTI.5017

    Ding, ding, ding... bells and whistles going off in our head, every time we see that we structure; what do we know it can do?--it can collapse; that is exactly what is going to happen.5029

    How do we collapse that?--it is going to be two arrows; we have the one group with the lone pairs forming the π bond; that is what is kicking the leaving group off.5040

    These two arrows are going to be very useful to us; you might see this mechanism drawn slightly differently in other textbooks.5053

    But look what happens when we use the two arrows to do that collapse; it brings us to a structure that we recognize; it is a carbonyl; we know what to do with carbonyls.5061

    Here if you are keeping track of all your ingredients, our leaving group just left; we just kicked out one equivalent of our methanol.5075

    Tell me about this oxygen that did the kicking out; this is a now positively charged oxygen; we have a carbonyl with a positive charge.5084

    What do we have?--we have a great electrophile; we just made a great electrophile; what is going to happen to that great electrophile?--it is going to look around for a nucleophile.5093

    What nucleophiles do we have?--we just formed methanol; methanol could add back in and go backwards; remember every one of these steps is reversible.5106

    But what nucleophile do we have the most of?--remember our solvent is water; we have a huge amount of water here; so water is going to be our nucleophile.5114

    It adds into the carbonyl; now we have a neutral methoxy up here; we have water attacking; what is left on this oxygen?5126

    We still have two hydrogens; any lone pairs?--we have one lone pair and a positive charge; very good.5142

    Where do we go from here?--now what?--if you are looking very carefully, you see that we just made a new CTI; that is quite true.5156

    If this CTI collapsed, who is your leaving group?--the water here is your good leaving group; so if this CTI collapsed, where would it bring you?5166

    It would go right back to where we started; again yes, water could add in; water could get kicked back out.5175

    In this case, collapsing the CTI is not going to move us in the forward direction; what will move us in the forward direction?5181

    We don't want water to be our leaving group; what do we want to kick out?--what do we want to replace?--we have two methoxy groups; we want to get rid of both of them.5188

    We have already gotten rid of one; what we eventually want to do is get rid of this other one; what we are going to need to do is make this oxygen the good leaving group, not this oxygen.5198

    How are we going to get there?--let's first deprotonate down here to go back to a neutral intermediate; I want you to look closely at this intermediate, see if you could describe it.5208

    How would you describe this intermediate when you have a carbon with a methoxy and an OH on the same carbon, an OR and an OH?--we call this a hemiacetal.5226

    Of course we went through the hemiacetal; we created this in the acetal formation mechanism; we have to go through that exact same intermediate and the acetal hydrolysis mechanism.5236

    We are here; how do we go from here to the carbonyl?--we said we wanted to get rid of that methoxy group.5248

    Let's protonate up on this oxygen because that is going to turn that top oxygen into the good leaving group.5254

    I feel that we are moving in the right direction here; it looks like a good leaving group; now how does this leaving group leave?--where do we go from here?5277

    Now we have a CTI; ding, ding, ding... we have a CTI; that is the one that has a group with lone pairs and a group with a positive charge; this is now our leaving group that we want to replace.5285

    We essentially went from one CTI and converted it to another CTI, the one that is going to move us in the right direction.5302

    We deprotonate at one position, reprotonate in the other position; now we are ready to kick out that methanol; how do we do collapse?5309

    How do we collapse a CTI?--how many arrows?--we are going to use two arrows; the lone pair forms a π bond; that is what kicks the leaving group out.5317

    Here we just kicked off our second equivalent of methanol; by using those two arrows, it brings us to a very recognizable intermediate.5326

    It brings us very close to our product because now we see the carbonyl; we know we have a carbonyl on our product; we see that we are once again just a proton away.5340

    We just have to deprotonate and we would get to our final product; let's do that; A- can grab that proton; I am going to work myself into a corner.5350

    Make sure you give yourself plenty of room, nice big blank piece of paper when you go to do these acetal mechanisms or acetal hydrolysis mechanisms.5363

    We are getting into the territory of giant mechanisms; don't be afraid to snake around up and down and work that way.5370

    Don't stop and redraw a structure so that you can go left to right because every time you redraw a structure, you have a chance for making mistakes and you have a chance for wasting time.5378

    Both of those we can't afford to do like when it is an exam situation; just go ahead and snake your way down the page; finally we get to our final product.5388

    Also resist the temptation where I now have to flip this over so it looks like the carbonyl up here; no, we are done.5396

    We are back at our aldehyde; we kicked out both of our molecules of methanol; we have completed our hydrolysis of the acetal.5401

    What other nucleophiles can we have to the carbonyl?--there is one more to take a look at; that is a nitrogen nucleophile; we are going to look at two types right now.5414

    We are going to look at either ammonia or a nitrogen with just one carbon group attached; we call those primary amines; it has the formula RNH2.5424

    Of course the nitrogen is going to be a nucleophile; we know the carbonyl is an electrophile; this is a reaction that again is typically acid catalyzed.5439

    If we were to look at the oxygen example, what happened when we had an alcohol?--you might think maybe we replaced the C-O double bond with two nitrogen R groups, kind of like an acetal.5451

    But that is not what happens with nitrogens because nitrogen can have three bonds; what happens instead is we simply replace the C-O double bond with a C-N double bond.5468

    That nitrogen had an R group attached; that R group is still there; that is the product that we get; this is called an imine functional group.5483

    When we have a C-N double bond, we call that an imine; what is the second product that is formed in this reaction?--what else is formed?5491

    We lose these two hydrogens and this oxygen; so eventually somewhere in the course of the mechanism, we are going to producing water.5503

    This is another case where every step, just like the oxygen, every step along the way is going to be reversible.5511

    The only way we can push it forward for the imine formation is we have to remove to drive the reaction forward.5517

    To push the equilibrium in the forward direction and remove the possibility of doing the reverse reaction, we have to remove the water as it is formed.5528

    Just a quick example; what is interesting about these reactions, it has the same general format.5540

    But this group, the one group that is attached to the nitrogen, you can have a wide variety of groups here; it doesn't have to be just a carbon.5547

    It could be another nitrogen; it could be an OH; it could be just about anything; but whatever is attached to this NH2 just is along for the ride.5557

    The way we can draw our product is we replace our C-O double bond with a C-N double bond; we know that nitrogen has three bonds.5567

    We take a look back to see what was attached to that nitrogen; in this case, it was a methyl group; that methyl group is still there.5578

    We know at some point these hydrogens must be lost because in order to get a neutral product, the nitrogen needs to have just three bonds and a lone pair.5585

    That is why we end up dropping the hydrogens and just carrying along that one alkyl group or whatever group happens to be attached.5594

    Let's see if we can do a mechanism for this reaction; let's assume we have an acid catalyst; I think our first step is going to be protonate.5606

    Where should we protonate?--the carbonyl is going to be the place to start; we could just say HA for our tosic acid in this case; we can protonate.5622

    This is a reversible mechanism, reversible step; of course you can protonate; you could deprotonate; what does protonation of the carbonyl do for us?5634

    It turns our good electrophile into a great electrophile; the presence of that positive charge tells me that it is even more electron deficient.5645

    It is really going to be looking around for a nucleophile; what nucleophile do we have around?--the amine is going to be an excellent nucleophile.5654

    In fact the amine is such a good nucleophile, it doesn't even have to have a protonated carbonyl; so you might see some variations in mechanisms when you are looking at imine formation.5661

    This is going to actually be done without the acid catalyst; but it is just nice to show that here.5671

    Our nucleophile is going to attack the carbonyl again reversibly so; this nitrogen now has the methyl; it still has two hydrogens.5679

    What we did was we protonated, then we attacked, and now we can deprotonate to get to a neutral product; I can have my A- come back... and go from here and get to this neutral product.5699

    Protonate, attack, deprotonate--such a common sequence we are going to see for acid catalyzed additions.5720

    We are halfway there; we have introduced the nitrogen; we still have this oxygen; where do we need to go?--we need to eventually get rid of this oxygen.5730

    Remember our second product here is water; we are forming water; that oxygen of the carbonyl is going to leave as water; how do we get that to go?5739

    We protonate the oxygen to make it a good leaving group; again anytime you are stuck here, you are at a neutral product, neutral intermediate, and you have to think about what to do next.5748

    Because we are in acid conditions, the way to get out of that hole is to protonate something; we could protonate this nitrogen but that would move us backwards.5757

    We could protonate this oxygen; that would move us forward; how is that a good thing?--what does that do for us, protonating that oxygen?5767

    How do I know that can take me forward in my mechanism?--not only did I make this a good leaving group, but I also made something else that is kind of special here.5777

    It looks to me like a charged tetrahedral intermediate; yes, this is another case, carbonyl chemistry, we are going to see this again and again, a charged tetrahedral intermediate.5790

    Which means the way I am going to get rid of that leaving group is I am going to collapse that CTI; I am going to use two arrows.5801

    This lone pair is going to form a π bond; that is when it is going to kick out water; here is the point in our mechanism where we lose our water molecule.5809

    Our product for this step is going to be the following; nitrogen with a double bond; of course that is an N+.5822

    We have one, two, three, four; nitrogen wants five; we have an N+ here; we have seen this part of this part of the mechanism before with oxygen.5830

    At this point when we have the oxygen, this is now when we added in our second equivalent of oxygen; we ended up with the acetal with two OR groups.5840

    But the nitrogen could do something different to stabilize this molecule; that is because nitrogen can have three bonds, wants to have three bonds to be stable.5849

    There is a very easy way for it to get rid of its fourth bond; what could we do here?--we can just deprotonate and get rid of that hydrogen; that is exactly what happens.5861

    Our A- comes in and deprotonates; and we are done; the imine mechanism is significantly shorter than the acetal because we didn't have to add in two equivalents of the nucleophile.5870

    We just add one equivalent; it ends up replacing both C-O bonds with C-N bonds; it could still accommodate this third group that it came in with.5881

    Another reaction that we can take a look at, moving away from nucleophilic additions to carbonyls, are oxidation reactions.5895

    This is where we increase the number of C-O bonds while decreasing the number of C-H bonds... the number of C-H bonds.5905

    The biggest case where this is going to be relevant is when we are looking at aldehydes because an aldehyde is the only carbonyl that has a C-H bond that can be lost.5918

    We can lose this in an oxidation; if we give a very strong oxidizing agent like Jones conditions, like chromic acid conditions, absolutely we can replace this C-H bond with a C-O bond.5930

    How would I finish up this structure to make it look like a recognizable functional group?--I would just turn this oxygen into an OH.5942

    We could take an aldehyde and convert it to a carboxylic acid by oxidation, by chromic acid oxidation like Jones conditions, sodium dichromate and acid.5950

    That is just like we have seen this before; we have seen Jones before; if we had a primary alcohol and we used Jones conditions, we made the carboxylic acid.5963

    We have seen this reaction before starting with an alcohol; we saw that if you partially oxidize it to an aldehyde, you wouldn't be able to stop; it would go all the way to the carboxylic acid.5975

    Here we are just seeing an example where if you started with the aldehyde, this could also be subject to oxidation and can go to the carboxylic acid.5985

    If we used our other oxidizing agents though like PCC or Swern, remember we used PCC or Swern to make an aldehyde; that means that they must not react with aldehydes.5993

    If we wanted to do that oxidation would be impossible; we need a strong harsh oxidizing agent, something like chromic acid.6004

    How about if we had a ketone; if we did Jones or PCC or Swern oxidation conditions, any of these, and we tried to do it on a ketone.6011

    Here is a case where there is no CH to lose; we are going to have no reaction with these; the only oxidation we could have would be breaking the carbon-carbon bond.6020

    That is going to be much rare and not going to happen with any of the oxidizing agents we have seen before that would oxidize primary or secondary alcohols.6032

    Very limited options here for oxidizing; we are just going to start with the aldehyde and do a strong oxidizing agent to make the carboxylic acid.6043

    When it comes to reductions of carbonyls, either aldehydes or ketones can undergo reductions.6055

    Remember a reduction now is going to be a decrease in the number of C-O bonds and an increase in the number of CH bonds.6063

    For example, we can go from a ketone or an aldehyde to an alcohol; that would be an example of a reduction reaction; how could we do that?6073

    There is two methods we could use, two types of reagents that will do this; one possibility would be using a hydride reagent.6084

    Something like a nucleophilic hydride like lithium aluminum hydride or sodium borohydride would work great here; that is taking advantage of the fact that this carbon is electrophilic.6092

    If we had a nucleophilic hydrogen, that would clearly add to the carbonyl and give an alcohol product.6106

    In fact we have already seen that in this lesson as one of the examples of the nucleophiles that can attack; that would be one way to reduce a carbonyl.6118

    Another option we have for reducing carbonyls, a very special kind of catalytic hydrogenation, using a special catalyst called Raney nickel.6128

    This is a nickel with hydrogen gas adsorbed onto it; this combination of hydrogen and a catalyst, it does a catalytic hydrogenation; but it is one that reduces a carbonyl.6138

    We have never seen that before; the only catalytic hydrogenations we have seen before have reduced carbon-carbon π bonds, either alkenes or alkynes.6154

    If we use this special catalyst, it will also reduce a carbonyl; just like we saw before for catalytic hydrogenation, you break the π bond; you add a hydrogen here, you add a hydrogen here.6164

    That would also give this alcohol product; what is new here is not just the OH, but it is this CH that is critical.6174

    But because it is catalytic hydrogenation, this is also something that would reduce an alkene.6181

    If you have an alkene in this structure and you want to reduce it to the alkane, you could use Raney nickel.6186

    But if you wanted to only reduce the carbonyl and not the carbon-carbon double bond, then we would use a hydride reagent instead which only is going to go after the carbonyl oxygen.6192

    Another type of a reduction would be to take a ketone or an aldehyde and completely reduce it all the way to an alkane.6205

    When you have a CH2 group, that is called a methylene; it is possible to reduce a carbonyl not only a partial reduction to an alcohol.6216

    But it is possible to completely reduce it to a methylene; again there is two good options for this reduction reaction.6227

    One of them is called the Clemmenson reduction; that is where you use a mercury zinc amalgam and HCl and water; it is called Clemmenson.6235

    Another option is a Wolff-Kirschner reduction; this is a two-step procedure; we add in NH2NH2; sometimes we just draw this as N2H4.6243

    That molecule is called hydrazine; first we treat the ketone or aldehyde with hydrazine; could we predict the product of this first step?--that would be an interesting thing.6252

    What happens with this first step if you were to take hydrazine and react it with acetone or some other ketone or aldehyde?6266

    What did we see as a reaction with a nitrogen, with an amine, and a carbonyl?--what is going to happen is we are going to replace the C-O double bond with an C-N double bond.6275

    Remember how I said whatever group is attached to the nitrogen is just along for the ride?--that is what we get; we get a C-N double bond with a nitrogen attached.6287

    These functional groups are called hydrazones; they have some interesting uses for analysis; if you react with hydrazine, you get a hydrazone.6297

    One reaction that hydrazones will undergo is when you treat them with base and heat, it will do an elimination reaction that replaces the C-N double bond with CHs.6314

    I am not going to talk about either of these mechanisms although the Wolff-Kirschner has a pretty cool mechanism.6325

    You would be able to do the mechanism for the first part; the mechanism for the second part is also an interesting one that you should be able to follow.6329

    But for the most part, these two are usually given as yet another set of reagents in order to do a synthetic transformation.6337

    If you wanted to take a carbonyl and reduce it all the way to the alkane, you could use either Clemmenson reduction or Wolff-Kirschner reduction.6347

    Can you think why chemists have developed these two complementary methods?--a lot of times we just give you one exemplary reagent to use for a given transformation.6356

    Why have these two maybe been used so widely?--it looks like clearly the Wolff-Kirschner reduction involves a strong base.6370

    The Clemmenson reduction, this is a redox reduction, doing a metal reduction; it uses acid.6381

    Clearly depending on the rest of your molecule, what other functional groups you have, in certain cases you would prefer an acidic reduction reaction versus a basic reduction reaction.6389

    That is why you almost always see Wolff-Kirschner and Clemmenson being presented in tandem as two complementary methods you can use.6400

    One last thing to talk about is the reason that we are looking at acetals; why are we spending all this time seeing acetals, looking at the mechanism, how do we make them, how do we take them off.6414

    It is because they have a very useful role in organic synthesis; they also have very useful roles in natural products.6428

    We will see acetals and hemiacetals in a variety of organic structures, especially sugars.6438

    But one other use that they have that is critical in organic synthesis is the use as a protective group.6445

    I just want to talk a little bit, now that we know about acetals and how to make them, I want to show an application of those as protective groups.6452

    The strategy behind a protective group is... let's imagine we are doing a synthesis of a target molecule.6462

    But instead of just having a very very simple target molecule where there is one functional group, let's say we have multiple functional groups.6468

    What we want to do is we want to do a transformation that involves just one part of the molecule; we want all the other parts of the molecule, all the other functional groups to not react.6475

    One way to achieve this and the way that is typically done is we use a protective group that we hide...6483

    We put on a protective group and essentially hide that functional group so that we could do the reaction somewhere else on the molecule.6492

    Then when we are done, we can take that protective group back off and get the functional group that we wanted.6500

    Again if you imagine a target molecule that you are trying to synthesize that has fifty functional groups on here; what we do is we kind of protect them all.6505

    Then we deprotect over here and we do a little manipulation; maybe we reprotect it; then we deprotect over here and we do a manipulation; we reprotect it.6513

    With the use of protective groups, you can make fantastically complicated molecules with a variety of functional groups.6521

    That might appear that you wouldn't be able to do some of those transformations without protective groups; let's see just how acetals fit in this picture.6530

    If you start with a carbonyl, if you have a carbonyl in your structure, we know those are excellent electrophiles; we have seen again and again how nucleophiles can add into them.6541

    If you treat it with an alcohol and you make it an acetal, it is no longer an electrophile, this structure has no leaving group; it has no π bond like the carbonyl did; it has no resonance.6550

    It no longer has the acidic hydrogen that we are going to see that ketones and aldehydes have, carbonyl compounds have; in other words, it is protected; we have taken away that electrophilic nature.6563

    If we try to react it with a nucleophile or a base, if we try to deprotonate it, if we try to do some kind of substitution or addition, it doesn't happen; there is no reaction.6578

    Like an ether is a pretty stable functional group and doesn't do a lot of reactions, acetals are very similar that way.6589

    In fact there is only one reaction that we have seen of acetals; that was the reaction of an acetal with H3O+.6597

    What happened there?--it underwent hydrolysis; it gave us back the carbonyl that we had started with.6605

    In fact this one reaction that it undergoes is useful to us because the key of having a protective group is not only that you can put it on and temporarily hide the carbonyl.6617

    But then you have to be able to take it off as well and get that functional group back; so acetals are really ideal for this situation.6628

    Let's see an example where you would need that; consider the following synthesis; let's say I wanted to make this target molecule.6636

    The plan that I had for that is I would start with this halide; I would react it with magnesium to make this Grignard.6645

    Then I would react with formaldehyde; that Grignard could attack the carbonyl and make this alcohol after a workup.6653

    Good idea, reasonable idea for handling the reactivity of this carbon; but what is the problem with it?--this reaction would never work; this synthesis would never work.6662

    Where do I have an error?--right here I have a Grignard which is a very strong nucleophile; in the same molecule, I have a carbonyl which is a great electrophile.6672

    In fact we just said that we utilize the fact that Grignards react with carbonyls; yet we had a carbonyl right here that we chose to ignore.6685

    You might say it can't happen intramolecularly because it is not the right distance away.6697

    But remember you never have a single molecule of this Grignard reagent; you have a solution of these Grignard reagents; you have millions of them.6704

    Even if they can't react intramolecularly, you certainly would have one molecule attacking the other molecule and doing a Grignard reaction that way.6715

    What would we have in this case, in this plan?--the synthetic plan is we come across some incompatible functional groups.6729

    It is impossible to have a Grignard in the presence of a carbonyl without having them react; how can I synthesize this molecule?6738

    I need to protect my carbonyl; I need a protective group; what I am going to do first is I am going to convert this to an acetal.6747

    This is where the diol comes in handy; a lot of times we will see this being used; of course you could use any alcohol you want.6759

    But if we use the diol, we would get this cyclic acetal; now our carbonyl is gone; our carbonyl is hidden; it is masked; there is no carbonyl any longer.6766

    Now if I took this structure and added magnesium, I could make the Grignard reagent.6785

    This Grignard is okay; it is possible to make this Grignard; these are now compatible; the Grignard would have no reaction with the acetal.6796

    I hid my carbonyl; now I can make the Grignard; I can use the Grignard; I can add in my formaldehyde; and my workup and do my Grignard reaction.6808

    Then at the very end, to get my desired target molecule, I need to remove the protective group; I need to get rid of that acetal; how do I do that?6825

    I use water and acid, H3O+; hydrolysis; I know how to put an acetal on with an alcohol and acid; I know how to take it off with water and acid.6835

    You will notice this workup for the Grignard was H3O+; then removing the protective group was H3O+.6852

    Sometimes we don't have to draw that twice; sometimes you can indicate this H3O+ is vigorous enough conditions.6857

    That it will both protonate the O- and it will hydrolyze the acetal; but maybe we could control the pH here to do them stepwise or so on.6864

    But sometimes you might see them all in one step or you might see them separately; this would be a great way to do a synthesis, have a synthesis be allowed, by using a protective group.6874

    While we are talking about protective groups as a general strategy, let me also introduce the fact that carbonyls are not the only thing that can be protected.6890

    A wide variety of functional groups that are protective groups have been developed for each of those functional groups; for example, an alcohol.6897

    An alcohol is another functional group that is ubiquitous; we have a lot of these; we want to be able to hide an alcohol.6907

    Most notably what we need to get rid of on an alcohol is the acidic proton because that can interact with different reactions; it will be available anytime we have a strong base.6917

    There are several strategies that we can have for this; one that is very commonly used is we take an alcohol and we treat it with trimethylsilyl chloride.6930

    This is called TMS chloride for trimethylsilyl chloride; we take this and some base; what happens is the silicon is going to attach the oxygen.6941

    We are going to lose this proton; we are going to lose this chloride; because we are generating HCl, that is why we need the base here, something like pyridine maybe.6953

    What happens is we attach the silicon onto the oxygen; it is like using tosyl chloride to make the tosylate.6963

    But when we use the TMS chloride, we get what is known as a silyl ether; this is another substrate that is very unreactive; like a regular ether, it is very unreactive.6972

    We no longer have the OH group here; we no longer have that acidic proton; so this is protected; it is protected as the silyl ether.6990

    You could draw this; usually we don't draw out our protective groups, we usually use abbreviations to represent them; this is called the TMS group; so this is called OTMS.7000

    There is a wide variety of silyl ethers we can use; instead of using a trimethyl, you can replace one of these with a tert-butyl; that is called tert-butyl-dimethylsilyl chloride, TBS or TBDMS.7012

    Or you could have three ethyl groups; that is called TES for triethylsilyl; a really wide variety that have different stabilities and different applications.7027

    But they all have these interesting abbreviations; when you are looking at a multistep organic synthesis in literature, it looks like alphabet soup.7036

    You see all these acronyms, all these abbreviations all over the place to represent the protective groups that are being put on and taken off at various points in the synthesis.7045

    What is really cool about silyl ethers and the reason they are so widely used is they are very stable to a variety of reaction conditions except for one.7055

    When we want to take them off, we need to be able to do that; the reagent we use for that is tributyl ammonium fluoride... I'm sorry, tetrabutylammonium fluoride.7066

    Which is called TBAF; it is called TBAF for short; when we are done with our silicon group and we want to take it off, we add in some TBAF.7089

    What happens there is... fluoride is something that loves silicon; it is going to attack the silicon and release the oxygen, something like this.7098

    F- will come in, attack the silicon, cleave that ether, and give us back our alcohol; how many reactions have we seen up till now that uses fluoride as a reagent?7114

    It is going to be very rare; we are not going to be using that ordinarily; we are not going to encounter that unless we want to remove a silicon protective group.7126

    This is another great strategy to hide an alcohol; we can protect as a TMS ether; then we can remove it by using TBAF.7133

    Let's see an example where we might need to use a protective group; in this transformation, we have two things we need to accomplish.7144

    We have a carbonyl that we are going to convert to an alcohol; have we ever seen that transformation?7152

    It looks like a reduction; we need to reduce the carbonyl at some point as part of our transformation.7159

    We also have this carbon as a bromine; now it has a carbon chain; that is a new carbon-carbon bond that we also need to accomplish as part of our synthesis.7170

    We need to do two things; we need to reduce the carbonyl and form the new carbon-carbon bond; we can do either one first; it doesn't really matter.7183

    Let's say we wanted to do this disconnection; if we wanted to do this disconnection first, we look at these two carbons and we say we want to make this.7192

    One of these has to be a nucleophile, one of them has to be the electrophile; because this is the carbon that now has an OH, what does that look like?7207

    I think this was my electrophile as a carbonyl; how about the other carbon?--how do we make this a nucleophile?7218

    Remember we have an alcohol product here; how do we make an alcohol?--what two ingredients do we need?--we want a ketone plus a Grignard.7228

    Ketone plus a Grignard gives an alcohol; this is my carbonyl; the other carbon we are going to make a Grignard.7239

    If I had this Grignard and this ketone... it is not really a ketone; it is two carbons; it is just this aldehyde; let's say it is a ketone in quotes.7252

    In this case, this is an aldehyde plus Grignard; if I had this aldehyde and this Grignard, that could make my product.7262

    That is a good plan; the problem is that this alcohol, that Grignard is impossible to make; we have another example of incompatible groups.7269

    It is incompatible because this Grignard is a very strong base, extremely strong base, just like we use butyllithium as a strong base; a Grignard would be a really strong base.7284

    Of course an alcohol is an acid; it is acidic; if you have a Grignard in the presence of an alcohol, it simply protonates the Grignard; you quench your Grignard; the reaction is over.7294

    There is no way you could use that; what we can do is we can protect; we have to protect our alcohol in order to do this Grignard.7305

    We have a plan here; let's think about getting to this alcohol first; how did we get this alcohol?--how do we go from a ketone to an alcohol?7317

    It looks like we have lost a C-O bond; it is a reduction reaction; what reducing agent would we use?--something like lithium aluminum hydride or sodium borohydride.7336

    You could do sodium borohydride and some kind of protic solvent like methanol or water or ethanol.7348

    We can do that reduction reaction no problem; then instead of making the Grignard, we have to first protect the alcohol.7355

    The way that we would protect the alcohol is we are going to protect it as a trimethyl silyl ether or any of the silyl ethers; but TMS is our most simplest one we can use, the most common.7366

    We could make the TMS ether; how do you make the TMS ether?--you use TMS chloride; you put a leaving group on that silicon; that is what gets replaced by the oxygen.7378

    Again some kind of base like pyridine we can use here; TMS chloride, pyridine would be a way of making the TMS ether.7388

    The reason I wanted to do that is because I wanted to make the Grignard here; I couldn't make the Grignard in the presence of an alcohol.7397

    Now I no longer have an alcohol; it is protected; now I can add in my magnesium; that has no effect on the TMS ether.7404

    This is protected; it is not acidic; so this is an okay Grignard; there is no problem; those are now compatible functional groups.7416

    What did I want to do with that Grignard?--I wanted to react it with acetaldehyde; I can bring in acetaldehyde, step one.7431

    Step two, H3O+ to workup my Grignard; I am running out of little room here; that forms the new carbon-carbon bond.7442

    We have done the reduction; we have formed the new carbon-carbon bond; we are very close to our final target molecule.7455

    All we have to do is remove the protective group that we put on; we are temporarily hiding a functional group while we do a reaction somewhere else on the molecule.7462

    Then we want to be able to take that protective group back off; how do we get rid of a TMS group?--we use TBAF; TBAF, tetrabutylammonium fluoride to do TBAF.7470

    This is one approach to the synthesis where we do our reduction first and then we do our Grignard; let's see if we could do the other order and see what that synthesis might look like.7483

    Let's say we wanted to do as our last thing, we wanted to do the reduction last which means we undo the reduction first.7496

    Then we could say now I want to do the disconnection of the alcohol which means I go back to my ketone and my Grignard.7511

    Once again this guy was my carbonyl; that was my electrophile who is now an OH; this was my nucleophile as a Grignard; ketone plus a Grignard gives an alcohol.7520

    I would need this Grignard plus the same acetaldehyde electrophile; what do I find in this case?--I have another example where I want to make a Grignard.7536

    Now I have a carbonyl; that is still no good; I can't have a carbonyl here either; this must be protected; I must protect this carbonyl because I can't have a Grignard in the presence of a carbonyl.7549

    Another way to do this problem would be to first protect the carbonyl; how do we protect the carbonyl?--we do so as an acetal.7561

    Again this diol is very commonly used; but you could just use a methanol or ethanol or any other alcohol you want; it is just convenient to draw that cyclic acetal.7570

    Now that I have my protective group on there, now I can make my Grignard with no problems, no incompatibilities; this is okay; this is perfectly fine to make.7585

    This is the protected version of the Grignard that I needed; the reason that I wanted this Grignard was I wanted to react it with acetaldehyde.7601

    Now I could say step one, put in my aldehyde; step two, H3O+; now I have formed my new carbon-carbon bond.7608

    Then as usual I want to get rid of my protective group; after I have done the reaction and I have gotten rid of that incompatible part, now I can remove my protective group.7624

    How do I get rid of an acetal?--how do I get rid of an acetal?--I want to go from the acetal back to the C-O double bond, back to the carbonyl; that is simply hydrolysis.7636

    Remember hydrolysis is the only reaction that we have for an acetal that is going to do strongly acidic conditions in the presence of a nucleophile like water--is going to give me back my carbonyl.7650

    What did I want to do with that carbonyl?--now I could react it with lithium aluminum hydride or sodium borohydride and H3O+.7662

    You might say I have hydride here; can't that react with the alcohol?--actually it can; but this is a case where LAH is pretty cheap; you could just use in excess.7677

    It is okay if you deprotonate over here; that won't stop the reaction with the carbonyl; then the aqueous workup can protonate both of them.7687

    Or maybe you could use sodium borohydride, NaBH4 and methanol, a weaker hydride reagent; then that would be compatible with the alcohol; either one of these would work well,7694

    But the point is in this reaction, because we want to do a Grignard and we have another functional group somewhere else in the molecule, if that functional group is a carbonyl or it is an alcohol.7709

    We have to protect either one of those; we have to protect them so that we could do the Grignard reaction; then deprotect them when that Grignard is done.7719

    Let's look at just a few more transforms, a few more examples, now that we are finished looking at reactions of carbonyl compounds.7731

    How about if we wanted to do the following transformation; we see that we have a three carbon chain here; let's find those three carbons.7740

    It looks like they are right here; one, two, three; what is nice about that is it tells us what disconnection we need to do.7749

    These are the two carbons that we want to bring together; as usual we have to ask what was our nucleophile, what was our electrophile?7758

    We are asking what starting materials do I need?--what starting materials do I need?--we have an alcohol that we are disconnecting; we have seen this again and again.7766

    When we do that the carbon that is now a single bond O-H used to be a C double bond oxygen; it used to be a carbonyl; this was my electrophile as a carbonyl.7779

    How do I make this carbon, an ordinary carbon, a nucleophile?--we add a metal; we make it a Grignard; the alcohol disconnection brings us back to a ketone plus a Grignard.7792

    Our Grignard is this guy; isopropylmagnesium bromide, for example; our carbonyl is not a ketone actually; it is an aldehyde; this is another example where we are using acetaldehyde.7805

    You could leave this structure like this, but we usually draw in that hydrogen there for the aldehyde; what is great about a retrosynthesis is you can check your work.7817

    You can say if I had this nucleophile, if I had this Grignard, and I had this electrophile, this aldehyde, would they come together to make my target molecule?7826

    They would; you can check that mechanism; you can double check; now you know you have a good plan.7836

    Now all we have to do is figure out how to make isopropylmagnesium bromide when we are starting with isopropyl bromide; that isn't too hard to imagine.7840

    All we need to do is thrown in magnesium; once we have the Grignard, we can add in our electrophile followed by H3O+ workup; and we have done our transformation.7848

    Let's see another one; now we have an interesting example; we start with a carbonyl; we want to go to an alkene; we could think about how do we make an alkene?7868

    The other thing we want to keep in mind is that we started with three carbons; we still have just three carbons; we did see a Wittig reaction as a way to make an alkene in this chapter.7883

    Remember a Wittig reaction adds carbons to the carbonyl carbons that are already there; because we haven't added any new carbons, we wouldn't want to be using a carbon nucleophile in this case.7894

    This is simply a functional group interconversion, a functional group interconversion because we are not changing our carbon structure at all.7905

    Then we think about we have an alkene; what are some ways that we can make an alkene?--what starting materials do I need?7913

    What functional groups have I seen where upon reaction they give an alkene product?--we also want to keep in mind that it came from something that we can make from a carbonyl.7920

    We are working forwards a little; we are working backwards a little; we are trying to find that key intermediate structure that we can both get to and go from.7935

    One reaction that is reasonable here is how about dehydration of an alcohol?--if I had an alcohol... I need to do some kind of elimination to form a double bond.7944

    I can either have an alkyl halide and do an E2 or I can have an alcohol and do an E17955

    What is great about an alcohol is I know that that is something I can create from a carbonyl; then I know that I can go to the alkene; that would be great.7962

    How do I go from a carbonyl to an alcohol?--that looks like a reduction reaction; this is lithium aluminum hydride, for example; two steps; H3O+; that give us an alcohol.7974

    Remember we also learned about Raney nickel; Raney nickel, NiH2 also does this reduction of a carbonyl to an alcohol; that would be fine too.7987

    Then once we have this alcohol, we want to dehydrate; we want to lose water; what conditions will remove water from an alcohol?7999

    We need a strong concentrated acid; something like H2SO4 and heat is a dehydration; this would be a good way to do this transformation.8007

    Again two simple reactions we have seen before; but using them in combination, now we see how to go from a ketone to an alkene.8016

    How about the next one?--we want to go from a... what functional group do we have here?--we have an acetal; we want to go to an alkane.8028

    The acetal is closely related to what functional group?--where do you get an acetal from?--you get it from a carbonyl; what is the only place we can go from an acetal?8040

    We can go to a carbonyl; that is the only place we can go; we start with a carbonyl to make an acetal; from an acetal, we can go back to the carbonyl.8051

    This must involve going back to the carbonyl; now do we know how to go from a carbonyl to an alkane?--that looks like some kind of reduction.8063

    So this second part is a reduction; this first part, what does it look like here?--is this an oxidation to get to a carbonyl here?8074

    No, remember we started with two C-O bonds; we still have two C-O bonds; it is not an oxidation; this is simply hydrolysis; acetals can be hydrolyzed to give the carbonyl.8086

    This first step is just H3O+; it gives that big long mechanism we saw for hydrolysis of an acetal.8097

    This second step, how do we go from a carbonyl all the way down to an alkane?--in other words, we want to have two hydrogens here.8104

    We saw two methods for this; we saw the Clemmenson reduction; we saw the Wolff-Kirschner reduction; either one is fine.8112

    Wolff-Kirschner is N2H4 and NaOH and heat; again get some flashcards together to become familiarized with these reagents.8119

    That is the Wolff-Kirschner, the Clemmenson, the zinc mercury amalgam, and HCl; those kinds of reaction conditions will be the acidic redox reaction.8132

    One last example; let's turn the table around and ask what starting material did I need to get to this product?8145

    If we are used to doing transform type problems and we are good at doing those planning, this is a piece of cake.8153

    Because that is every time we do a retrosynthesis, we are asking what materials did I start with?8160

    The key is this is our final product and what was the reagent that we reacted it with?--we had a phenyl group plus a CH2; we had a one carbon plus the phenyl group.8167

    Here is our phenyl group; here is our CH2; this is the new carbon group that has been added.8178

    Furthermore we have a benzylmagnesium bromide; we have a Grignard reagent; what is the reactivity of a Grignard reagent?8186

    This is a nucleophile; we already know that carbon 1 here was our nucleophile; even if we couldn't see it for ourselves, we know what is required; we need a two carbon electrophile.8193

    This was an electrophile; what is it going to look like?--what electrophile can we have that after a Grignard adds to it, we are going to have an OH here?8207

    It is going to be a carbonyl; it going to be a carbonyl; what we need is a two carbon; we could draw it upside down if you want so that you can track along.8216

    A two carbon carbonyl; this aldehyde, once again here is another example of acetaldehyde; then we could treat it as a predict-the-product; see if we got it right.8226

    If we had this Grignard, it would attack the carbonyl, break the π bond, and after a workup, we would get this phenyl plus these three carbons; that would be our final product.8236

    So a lot of interesting things we can do with carbonyls, ketones and aldehydes; we can do some oxidations and reduction reactions.8247

    But the vast majority of our reactions are going to be reacting the carbonyl as an electrophile.8255

    We add a variety of nucleophiles; wee could add the hydride; we could add Grignard; we could the Wittig nucleophiles.8261

    Then we get to the alcohol and amines, we get some of these reversible reactions where we form acetals and we form imines.8267

    Of course the importance of acetals not only extends to natural products such as sugars; we will see that down the road; but also they become very useful in organic synthesis as protective groups.8275

    Thanks for joining me; I look forward to seeing you again soon.8289