Enter your Sign on user name and password.

Forgot password?
Sign In | Sign Up
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

Enols and Enolates, Part 1

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 (23)

1 answer

Last reply by: Professor Starkey
Tue May 1, 2018 12:05 AM

Post by Carol Moghnieh on April 28 at 11:01:26 PM

Hello Dr. Starkey,

In Claisen condensation, we did a final deprotonation that was the driving force for claisen, but after workup its the exact same molecule before having deprotatonated it. I'm not too sure what was necessary with that step, can you please clarify it for me

-Carol

2 answers

Last reply by: Brijae Chavarria
Mon Mar 9, 2015 12:59 PM

Post by JaeYoung Sim on April 1, 2014

I download all power point and print out to study but why the slide order dose not match with lecture slide order? I am just so confused. How can do arrange these slide order?

2 answers

Last reply by: Some one
Wed Apr 24, 2013 4:17 AM

Post by Some one on April 23, 2013

Hi professor, we mentioned that it usually takes strong nucleophiles to attack the carbonyl carbon, such as LAH and Grignard reagents. What makes the enolate such a strong nucleophile in the aldol reaction that it would disrupt the resonance stabilized carbonyl. Thank you so much.

1 answer

Last reply by: Professor Starkey
Mon Apr 22, 2013 6:55 PM

Post by Some one on April 22, 2013

Hello professor, why is C-alkylation preferred over O-alkylation on an enolate?

1 answer

Last reply by: Professor Starkey
Sun Mar 31, 2013 12:35 PM

Post by Marrbell Martey on March 30, 2013

What would the product be if aldehyde is used in Dibenzalacetone formation

1 answer

Last reply by: Professor Starkey
Sun Apr 29, 2012 9:38 AM

Post by Rachel Paquette on April 27, 2012

at 41:00 you are explaining the mechanism for the aldol condensation, and you say that the alpha hydrogen will be deprotonated because that is the theme but if you have OH wouldn't you be able to attack the carbonyl carbon and then move the electrons in the double bond move up to the oxygen? how do you know whether you are deprotonating the alpha hydrogen or attacking the carbonyl carbon

0 answers

Post by Misael Nieto on March 28, 2012

I love the detail in this lectures. Thankyou

1 answer

Last reply by: Professor Starkey
Mon Jan 23, 2012 11:29 PM

Post by Jason Jarduck on January 22, 2012

Hi Dr. Starkey,

I like your lecture alot!! Today I watched the complete lecture to find the answer to a question.

Thank you

Jason Jarduck

0 answers

Post by Jamie Spritzer on August 12, 2011

in 15:49, where is the counter-ion Na+ going to be? If there are 2 resonance forms, is it with one O- or the other one, depending on the resonance form?

1 answer

Last reply by: Professor Starkey
Thu Oct 27, 2011 11:02 AM

Post by Jamie Spritzer on August 10, 2011

In 65:22 the base LDA is used to deprotonate, but in the second step at the end, there is an acidic workup with H3o+. How can you have both acid and base in the same mechanism?

1 answer

Last reply by: Professor Starkey
Thu Oct 27, 2011 11:05 AM

Post by Jamie Spritzer on August 7, 2011

Is the acidity of the alpha proton in a carboxylic acid about the same as for an ester?

0 answers

Post by Senghuot Lim on July 17, 2011

i bow down to the god of Ochem

Enols and Enolates, Part 1

Draw the tautomerization mechanism for this reaction:
  • Resonance-stabilized cation:
Draw the stepwise mechanism for this reaction:
Draw the product for this reaction:
Draw the product for this reaction:
Draw the product for this reaction:
Draw the product for 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

Enols and Enolates, Part 1

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

    Transcription: Enols and Enolates, Part 1

    Welcome back to Educator.com.0000

    Today, we are going to talk about enols and enolates, which are components of aldehydes and ketones.0003

    So far, what we have seen for aldehydes and ketones involved the reactivity of the carbonyl, the C-O double bond; and the most significant part that we have seen so far is the polarity of the C-O double bond due to the resonance, which makes this carbon partially positive and makes it an electrophile.0010

    In other words, nucleophiles add here; and that is certainly a significant reactivity of aldehydes and ketones--of any carbonyl.0030

    What we are going to shift toward in this lesson is looking at the alpha carbon (that is the carbon right next to the carbonyl): and consider the protons that are attached to that carbon.0041

    It turns out that these protons, the alpha protons, are acidic: and what does it mean to be an acid?--it means you donate a proton.0052

    In other words, they can be deprotonated.0063

    In this lesson, we are going to explore the deprotonation of the α carbon and the consequences of that deprotonation.0069

    One other component that is of interest to us in this unit is the idea that any carbonyl-containing compound (like a ketone or an aldehyde) is in equilibrium with another form called an enol.0077

    Now, this structure is called an enol because it has an alkene (a carbon-carbon double bond) and an alcohol (OH), and they are on the same carbon.0093

    The interconversion between a ketone and its enol form is known as a tautomerization, and as you can see, the equilibrium is favored in the reverse direction here: the ketone is more stable.0104

    Having that carbonyl there is preferable, so that is the form that it prefers to be, but what is important to recognize is that there is always a small amount present here of the enol--a small amount present at equilibrium.0117

    So, in other words, any time you have a ketone or an aldehyde or any carbonyl-containing compound, you also have some of the enol form around; that is going to be important to us when developing some of the mechanisms, down the road.0136

    Let's look, first, at this tautomerization mechanism: how do we go from a ketone to an enol?0149

    First, let's draw the enol form, because that is going to be helpful for us to get from one place to the other.0155

    Let's think about where we are headed; and when we compare these two structures, we see that there are two things that need to be accomplished, and that is why we have a two-step mechanism here.0165

    It looks like we have an oxygen here, and now it's an OH; so one of my steps is: I need to protonate here at this oxygen--I need to add a proton at some point.0175

    And here we have a CH3, and now it's a CH2, so I need to deprotonate down here.0187

    And, of course, the π bond has moved as well; that is going to be part of our mechanism, and could be seen as resonance, too.0195

    The only question we have is: those are our two steps--what step are we going to do first?0203

    Well, typically, this tautomerization--the presence of enol is going to be something that we find in acidic conditions, so in acidic conditions, let's protonate first; so that is going to be our step 1 (protonate), and step 2 is going to be deprotonate.0207

    So, I can protonate; let's add in our lone pairs on this oxygen: step 1 will be "protonate the carbonyl oxygen."0220

    That is going to give an oxygen with three bonds and a lone pair: 1, 2, 3, 4, 5; that is a positively charged oxygen.0239

    OK, and my second step, then, is going to be to deprotonate this α carbon.0248

    It turns out we are deprotonating right away; so instead of making a CH3, let's make this a CH2, so that we can see one of the hydrogens involved.0255

    What we want to do is deprotonate that hydrogen; we can use the A- that we formed in this first step to be a base; and can you see how the mechanism might work to get us to our enol structure?0263

    Typically, when you do a deprotonation, the electrons just go and sit on this atom; but instead of moving them here, we can move them over to be a π bond, which would push this π bond up onto the oxygen; and now, we end up with the best resonance form here, where we have no formal charges.0280

    Any time we need to do a tautomerization, it is going to be a two-step mechanism; and we should practice this both forward and backwards until we get pretty good at it, so that it will be automatic when it comes to part of a larger mechanism.0298

    Let's take a look at that reverse mechanism.0312

    We have an enol, and we want to go back to the ketone.0316

    This is now the more favorable mechanism that we will see, and what do we have to do?0321

    Well, again, it is still going to be two steps: the reverse mechanism (we already have it written down here) is going to be the same number of steps and involve the same intermediates as the forward mechanism.0328

    And so, what do we need to accomplish?--well, we have an OH that now needs to go back to an oxygen; so one thing I need to do is: I need to deprotonate.0339

    It really helps to think about where you are headed and what you have to accomplish before you dive into a mechanism.0350

    And my CH2 becomes a CH3, so I am going to protonate in this position.0355

    Those are going to be my two steps: and what do you think we should do first?0364

    Well, I am thinking again, because we are in acidic conditions, we should protonate first; so that should always be our first step in our tautomerization.0367

    Let's redraw this: I need to protonate at that CH2; so I can bring an acid over here, HA, and how could I protonate this carbon?0375

    Well, I can use this π bond as my base; I can grab that proton, and that way, I can add a proton to that position.0388

    What happens to this carbon now: it only has three bonds, and so I have a positive charge.0401

    Just like any time I protonate a π bond, like we saw for alkenes, you get a carbocation as your product.0405

    Our second step (that was step 1: to protonate): step 2 is going to be to deprotonate, so I can bring my A- in here to deprotonate this oxygen.0412

    Once again, rather than deprotonate and give an O- next to a C+, my mechanism would be much more efficient if I grabbed that proton and took these two electrons and filled them in as a π bond between the carbon and the oxygen.0423

    There we go--our two steps, and we have gone from our enol to our ketone.0442

    Now, I mentioned at the beginning that we are going to be able to deprotonate α carbons, and let's think about why a ketone's α protons would be acidic.0449

    As usual, any time we want to determine something about the acidity of a compound, we should take a look at the conjugate base, and see how stable that is.0459

    Here is an α proton; the pKa for such a proton is on the order of about 20, and if we imagine deprotonating it (treating it with some strong base that can come in and remove it), we would get this carbanion.0466

    Now, normally a carbanion is not a very happy charge, because carbon doesn't like having a negative charge; but there is something about this conjugate base that makes it reasonably stable.0483

    Well, that is because the lone pair is allylic; it is next to a π bond; in fact, it is next to a carbonyl, which means it has resonance; I can delocalize this charge.0494

    Any time I have an allylic lone pair, I can bring the π bond in, and bring this π bond up, and I can draw a second resonance form.0506

    Any time I could draw a second resonance form, that is always a good thing; and that explains why this is a reasonable place to deprotonate, because the conjugate base is resonance-stabilized.0516

    It is a resonance-stabilized carbanion; so it is a carbanion, but it is stabilized by resonance.0533

    And we can not only delocalize that charge, but we could delocalize that charge to the more electronegative oxygen; so this is an excellent resonance form.0543

    Now, there is a name for this resonance-stabilized carbanion: it is called an enolate.0550

    We just saw what an enol looks like: an enol has a double bond with an OH attached to that, right on that double bond; an enolate is the charged version of that structure.0555

    We have a double bond with an O- attached to that same carbon.0566

    And so, as you could see, the title of this lesson is "Enols and Enolates"; so those are going to be the two species that we are going to be interested in both forming and reacting.0569

    It turns out that we are going to be using both the enol and the enolate; if we have acid-catalyzed mechanisms, that is when we will be using the enol version of this compound, and in a base-catalyzed mechanism is when we are going to be using the enolate version.0586

    So, we will see many examples of these in the following slides.0601

    Now, before we progress, though, I want to talk a little bit about deprotonating a carbon; that is not a very easy thing to do.0607

    We are going to see repeatedly, throughout this unit, that we can do it for α carbons; let's think about other types of CH's.0614

    OK, if you have an alkyne, that has a reasonable pKa, as well--somewhere around 25; that means...that is a low enough number that, if you do treat it with a strong base, it is possible to deprotonate here and form this carbanion.0623

    Remember, this is sp hybridized, and that is what made this possible; and this is an OK carbanion to make.0637

    We have made these; we have used these in synthesis; and this is something that you should recognize as a staple carbanion.0647

    OK, however, if you tried to do that same thing with an alkane or an alkene--if you try to take an sp3 hybridized carbon or an sp2 hybridized carbon and try and do the same thing and react with a base, you would get a completely unstable carbanion here and a completely unstable carbanion here.0654

    We cannot deprotonate alkanes and alkenes; OK, it is possible to deprotonate alkynes, and the focus of this unit, of course, is deprotonating α carbons, such as aldehydes and ketones.0674

    Now, if we are going to be protonating, that means we need a base; let's think about what bases are possible.0689

    If you had to name a base, you might say something like sodium hydroxide; we know that is a good base, so let's try that.0693

    Let's react this with sodium hydroxide and think about what product we would get.0699

    OK, I could use hydroxide here as my base; it can grab this proton; and rather than have the electrons sit right on carbon, most often, when we deprotonate an enolate, we are going to go right to that better resonance form.0707

    We are going to take these electrons and form a π bond and move those electrons all the way up to be on that oxygen.0723

    That is the preferred resonance form--that is the better resonance form.0729

    We can go ahead and draw the enolate that way.0733

    OK, we can get that enolate; and what is the other product here?0737

    If I used hydroxide as my base, I just formed water.0741

    Now, water has a pKa of about 16, so when we compare these two acids, the acid in the forward direction has a pKa of 20; the acid in the reverse direction has a pKa of 16.0746

    Which is the stronger acid?0759

    Water is the stronger acid; and how does the equilibrium lie in a proton transfer reaction?--it always lies in the direction of the weaker acid-base pair.0761

    So, this reaction can happen, but just to a small extent; it is actually the reverse reaction that is favored in this case.0772

    So, if I were to use a base like sodium hydroxide, what would happen is: I would deprotonate just a small amount of this ketone; I would make a small amount of the enolate; a small amount of enolate will be present at equilibrium.0780

    But, for the most part, the ketone would still be a ketone; it would be the neutral form.0802

    This is exactly the situation we want in certain reactions; so in those cases, we use sodium hydroxide.0808

    We also want to recognize--let's just make that note here--we have a large amount of the neutral ketone or aldehyde present at equilibrium.0817

    So, with a weak base like hydroxide, we have mostly ketone with a tiny little bit of enolate around.0830

    If we wanted to completely deprotonate the ketone or aldehyde to make it an enolate, 100%, we are going to need a much stronger base.0837

    One of the bases that has been developed for this, that is used very widely, is this one; this is called lithium diisopropylamide (that means we have an N-).0846

    Lithium diisopropylamide is very conveniently abbreviated as LDA; and this is a great base, because it is very strong base, and it is very bulky (having those two isopropyl groups introduces a lot of steric hindrance).0858

    That makes it a non-nucleophilic base.0876

    So, in other words, LDA is just a base; all it does is find a proton to take, and that is its only purpose.0882

    Where do we have acidic protons?--of course, the α protons are acidic, so we can deprotonate here.0890

    Again, we could show that mechanism; the N- can come and be the base, and we can make this enolate.0897

    This would be the lithium enolate; it would be the lithium cation here, because it's lithium diisopropylamide.0907

    We most often don't have the counterion there, but of course, it's there every time we have a negative charge.0914

    OK, but the other product here, now, is going to be diisopropylamine: diisopropylamine has a pKa of around 40--this is a very, very weak acid.0920

    That means this reverse reaction of having an enolate try and deprotonate diisopropylamine is very, very small: essentially nonexistent.0930

    We can think of this as a one-way street--as a way to completely deprotonate a ketone or an aldehyde and convert it to its enolate form.0939

    Now, we don't always have to use LDA to do a complete deprotonation; there are cases, like this one, known as an active methylene; an active methylene is when you have this situation, where this carbon is between two carbonyls.0951

    That makes it even more acidic: the pKa...let's compare it to this α carbon (this α carbon has just one carbonyl, so it is similar to an ordinary ketone): this has a pKa somewhere around 20.0971

    OK, but when you put one next to 2 carbonyls, you have a pKa somewhere around 11.0986

    So, it is orders of magnitude more acidic.0992

    When you think about deprotonating anywhere else, neither of these is at all acidic, being next to an oxygen or just being a plain old alkyl; remember, we are never going to deprotonate an ordinary alkyl hydrogen, so these are not acidic at all.0997

    It is only the ones that are going to be α to carbonyls that we are going to be considering deprotonating in this unit.1016

    Sodium methoxide is a good base; so we could use that as our base, and if we did that, we would (let's just draw a line drawing here) deprotonate this completely.1021

    Again, the reverse reaction is minimal; we can completely deprotonate this α proton, and that is because this enolate not only has the carbanion (and we could delocalize it into this carbon on this oxygen on the left--the carbonyl on the left), but this could also have resonance to the other carbonyl, and that is what makes this conjugate base so very stable, and therefore makes the parent acid so acidic.1038

    OK, my other product here--if I used ethoxide, it gives me ethanol; that has a pKa of somewhere around 18.1070

    So again, comparing a pKa of 11 to a pKa of 18, that is a huge difference, and that strongly favors the forward direction and negates the reverse direction.1079

    This is called a stabilized enolate: when we have something that is next to two carbonyls that resulting enolate has extra resonance, and so we describe it as a stabilized enolate.1091

    In this case, you could use LDA; but as usual, we always want to use a reagent that is the lowest reactivity, most stable; that makes it easier to handle and less expensive.1108

    And so, sodium ethoxide would work just as well here, so we would use that.1118

    Just a quick question: we talked about how sodium hydroxide is something that can be used to form a small amount of enolate: why not use sodium hydroxide in this case?1122

    That certainly is on the order of the same basicity as ethoxide, so it would also do a good job of deprotonating this.1133

    But is there another reaction that can happen if I use sodium hydroxide as a base instead of sodium ethoxide?1141

    Well, take a look here: we have an ester in this starting material; so what would happen if you took this ester?--there is another reaction that can happen, besides just the acid-base reaction.1150

    We could also have hydroxide add into the carbonyl, and then come back down and kick off the ethoxide; so we could also get hydrolysis substitution--an acyl substitution--here, if we used hydroxide.1163

    Notice: because this is an ethyl ester, what base did we choose to use? we used the ethoxide.1177

    OK, so the key here is: for esters, when we go to choose a base and we want to deprotonate α to an ester carbonyl, we are going to use the matching base.1186

    So, if we have an O-R ester, we are going to use the alkoxide that matches that; so if it's a methyl ester, we use methoxide here; we had an ethyl ester--we used ethoxide; and that is to avoid the substitution reaction that can happen with the carbonyl.1202

    If you have ethoxide, ethoxide can add into this carbonyl, but what is it going to be kicking out?1219

    It is going to be replacing ethoxide; so that reaction becomes invisible, and no longer a side product.1223

    Now, I just started to introduce how you could have esters be deprotonated at the α carbon; and that is true--we are focusing most of our reaction on aldehydes and ketones initially.1231

    But you can have any carbonyl; so here we have a proton that is α to a carbonyl that has a pKa somewhere around 20; we can deprotonate here.1243

    Here we have, again, an α proton that is next to a carbonyl, but that carbonyl happens to be an ester; that is still acidic--not quite as acidic as the ketone, but it is still acidic, and we still can deprotonate here.1253

    OK, but carbonyls are not the only groups that impart acidity to the carbon adjacent to it.1266

    OK, the nitro group, the NO2 group, also makes this carbon acidic--in fact, significantly more acidic than having just a carbonyl.1273

    And the cyano group is another group that makes α carbons acidic, kind of like the same as an ester might.1285

    OK, and let's think about...let's draw those conjugate bases to see if it makes sense to us; this should make sense on why each of these hydrogens is acidic.1294

    If we have a ketone, and we put an anion here, why would that be an appropriate place to have an anion?--well, because it is next to the carbonyl, and it can have resonance.1307

    OK, how about if I had an ester?--I'm sorry...I have an ester...I have a methoxy group over here, instead of just a methyl group.1322

    Well, we could still have resonance here, and this is still a resonance-stabilized enolate, so you can make the enolate of an ester, just like you can for a ketone.1332

    OK, but how about the nitro or the cyano?--well, let's take a look at the structure of the nitro group.1343

    Let's imagine deprotonating; so we just lost a proton here, and we now have this anion.1348

    When you draw out the nitro group, it looks something like this; and how would that be a stable carbanion?1356

    Well, this can have resonance just like a carbonyl can; we have an N-O double bond instead of a C-O double bond; but just like the carbonyl could, we can use that to delocalize the negative charge and move it to an oxygen atom.1370

    Of course, having a negative charge on an oxygen atom means this is a very good resonance form.1385

    OK, plus you have this positively charged nitrogen pulling electron density and stabilizing inductively; that is why this is even more stable than an enolate; it makes the α proton so much more acidic.1390

    How about a nitrile?--let's imagine this anion and draw out the nitrile: a nitrile, of course, has a C-N triple bond.1401

    Well, again, we have an allylic negative charge and an allylic lone pair, so the lone pair can come in, and the π bond can move over.1411

    We can have resonance; it puts the negative charge on nitrogen; that is not as good as oxygen, but it is certainly better than carbon, and it is because of this resonance stabilization that it makes it a reasonably acidic proton and something we can deprotonate with a strong base like LDA.1420

    These are enolate-like species; when we say "enolate," we mean a carbonyl of some kind--either a ketone or an aldehyde or an ester; but these are enolate-like species, as well.1437

    Just a quick question: there is a big difference here--5 orders of magnitude less acidic for an ester, compared to a ketone: why do you think that is less acidic--what is there about this conjugate base that is better than this conjugate base?1451

    Or why would a ketone be less willing to donate a proton?1467

    It must have something to do with this O-R group: well, remember: what effect does this oxygen have to the carbonyl next to it?1471

    It is an electron-donating effect to that carbonyl.1479

    So, an ester carbonyl is more electron rich; so that means it does not want to have this negative charge--this negative charge, now, has to compete with the oxygen's electron donation for this carbonyl, so there is less resonance stabilization that can go on to delocalize that negative charge.1485

    OK, so it is because the ester carbonyl is more electron rich that that makes it a weaker acid.1509

    Just to summarize: the carbonyl, the nitro, the cyano...each of those groups are described as electron-withdrawing groups (or EWG for short); and what they all have in common is: if you put a negative charge right next door to them, they would be able to stabilize that negative charge by resonance.1519

    That puts these three groups together in a certain category; we are going to see lots of examples, actually, where the EWG comes into play, and imparts a particular reactivity to the groups attached to it.1539

    So, now that we have taken a look at how to make enolates with a mechanism, what kinds of bases we can use, what types of α protons are going to be acidic...what would we do with an enolate--how are they used?1555

    Well, they are carbanions; they are examples of carbons with a negative charge, which makes them good nucleophiles: anything that is electron rich is going to be a good nucleophile.1567

    And so, we are going to react it with a variety of electrophiles.1578

    Electrophiles are things that are electron poor: things like an alkyl halide--that is an electrophile we have seen: we know that this halogen (chloride, bromide, iodide...) pulls electron density from this carbon, making it partially positive.1582

    So, we can have nucleophiles attack here, doing something like an SN2 mechanism, for example; and so, an enolate would be an example of that.1600

    OK, or even just Br2 or a halide like that--it doesn't have a carbon bearing a leaving group, but it has a halogen bearing a leaving group.1613

    For that same reason, you could have an SN2 occurring with that; we will see reactions of enolates with something like Br2.1624

    Now, a carbonyl has a partial positive/partial minus; so we have seen carbonyl reactivities as electrophiles, and we will see something like a ketone, aldehyde, ester...OK, in general, any carbonyl would be a good electrophile; and we will see enolates react with those.1635

    And finally, an epoxide would be a good electrophile, as well; remember, the carbons of the epoxide are partially positive, because the oxygen pulls electron density.1657

    There is a lot of ring strain involved in that: it's a three-membered ring, and so those also readily react with nucleophiles.1667

    Let's look at some of these examples.1674

    The first one, reaction of an enolate with an alkyl halide, is described as an alkylation reaction, and let's take a look at this reaction sequence.1677

    If we were to take cyclohexane and first treat it with LDA (remember, that is lithium diisopropylamide), every time we see LDA, we know that we have a base, a strong, bulky base.1685

    And what do bases do?--they deprotonate.1699

    So, we look at cyclohexane and ask, "Where can we deprotonate?"1703

    And of course, it is that α proton that is going to be acidic; so step 1 is going to deprotonate the α carbon to give us a carbanion.1706

    OK, and what I'm suggesting is that this carbanion, now, is going to be a very, very good nucleophile.1719

    In step 2, when I react with methyl iodide (which is a good electrophile), what reaction can happen here?1726

    I think the nucleophile is going to attack the carbon and kick off the leaving group; that looks like a back side attack--it looks like an SN2 mechanism.1736

    That is exactly what happens, and I have now installed a methyl group at the α carbon; so this is called an alkylation or an α alkylation reaction.1744

    It is this two-step process: we deprotonate, and then we treat it with an alkyl halide.1759

    Now, because it is an SN2, remember, that back side attack requires minimum steric hindrance, so we have to have an unhindered alkyl halide; a methyl group would be great; primary would be fine; but as soon as we get to secondary or tertiary, then E2 is going to be preferred, because the enolate is still a pretty strong base.1764

    Now, as shown here, the enolate is a nucleophile at carbon: in other words, C alkylation--putting the alkyl group on the carbon--is preferred, rather than O alkylation.1783

    OK, and this is important to point out, because remember: the enolate has two resonance forms.1794

    It doesn't matter which resonance form you draw; you should still be getting the same product.1800

    OK, so let's take a look at the mechanism using the better resonance form, the preferred resonance form.1804

    What we'll do is: we will have our base, our LDA, come in and deprotonate; but instead of putting the negative charge on this carbon, the more appropriate place to put that negative charge is on the oxygen.1810

    I am going to draw the enolate like this.1825

    Now, that is the better resonance form, because it has the negative charge on the more electronegative oxygen; in other words, this better represents the actual hybrid of the enolate structure.1831

    However, it is very tempting now, when you look at this, to think, "When I bring this together with my electrophile, it's very tempting to use the negative charge from oxygen to go and attack."1841

    That would be described as O alkylation, where the alkyl group ends up on the oxygen; that does not happen.1854

    That does not happen; it is the α carbon; it is the α carbon that is the nucleophile in an enolate, no matter how you draw it; it is the α carbon.1860

    So, how do I get this carbon to react?--well, this is what enolates do: the enolate is here: the enolate is a nucleophile; and I'm going to start with the lone pair up on the oxygen, but instead of having that attack the electrophile, it's going to come down and re-form the carbonyl, and that is going to push these electrons out.1871

    We are going to form this bond here between the α carbon and the methyl group.1889

    These two electrons are going to come and attack the carbon, and that is what kicks off the leaving group; so it is the α carbon that is nucleophilic and does the SN2.1894

    So now, when we follow the arrows around, I see that I am back--my oxygen has two lone pairs; I have my carbonyl back; and attached to that α carbon, I have my alkyl group.1905

    OK, this is typically how we are going to be drawing our enolates for the rest of the chapter, and how we can use them.1917

    This is not wrong; this is still an acceptable drawing of an enolate; it is just not as good a representation as this one.1924

    We want to get used to using this mechanism.1933

    What else can we do with the α carbon?--we can also halogenate at the α carbon; that reaction is described as the α halogenation.1940

    Here is an example: if I take this ketone and treat it with chlorine and base with water, I can install a chlorine in the α position.1947

    Now, that mechanism is analogous to the one we just saw for α alkylation; we deprotonate the α carbon, and then we attack the Cl2 to put in the chlorine.1959

    OK, and we can look at that reaction; but this reaction is not that useful, because this product that we formed--if you take a look at that α carbon, it turns out that this is now more acidic than your starting α carbon.1969

    And why is that?--well, we just added a chlorine here; we know chlorine pulls electron density; or any halogen is electronegative and pulls electron density here; so that enhances the acidity here and makes it easier to deprotonate here.1987

    So now, I am going to be forming some of this enolate, and I'm going to end up adding a second chlorine; so we could have multiple halogenations.2000

    This would not be a very good way to make this 2-chloro, (1, 2, 3, 4, 5) 3-pentanone, because it would be hard to stop in this case.2010

    Any time your product is more reactive than your starting material, it is difficult to control those reactions.2021

    OK, in fact, it is so reliable that there is a test called the iodoform test that counts on this overreaction.2027

    It is when you have a methyl ketone (so I have a CH3 here, and attached to a carbonyl, that is called a methyl ketone)--if you treat a methyl ketone with iodine and sodium hydroxide, what happens is: you end up replacing all three of those protons with iodines by successive α halogenations.2035

    And that turns this group into somewhat of a leaving group; now, it's very unusual to have a carbon leaving group, but because that carbon has three iodines on it, all pulling electron density away, it is a reasonable leaving group.2058

    And so, hydroxide can add into the carbonyl now and do a substitution reaction.2073

    We can get a CTI, and again, even though we don't normally think of this carbon as a leaving group, it can, in fact, get kicked out; and the product we are going to get--we will get CI3-, which gets protonated to iodoform.2081

    We will get the carboxylic acid product out here when we are done; and this ends up being a precipitate; this is a yellow precipitate, and this is the test.2098

    The iodoform test is when you treat a sample with iodine and sodium hydroxide; if a precipitate forms, then that is a chemical test, a qualitative test, to indicate the presence of a methyl group attached to a carbonyl.2110

    So, these kinds of tests are outdated, now that we have such powerful spectroscopic techniques, like NMR, where you can really see a methyl ketone a lot less ambiguously.2124

    But this still has some historical note, and you will often see this reaction still, in textbooks.2135

    With a base-promoted reaction, we expect to have multiple halogenations.2141

    If we want to do a single halogenation, that is possible; but what we are going to do is: we are going to use acid-promoted reaction conditions instead.2147

    In this case, if we used Br2, but with acetic acid now instead of a base (because here we see a carboxylic acid, so we recognize that these are acidic conditions), it is possible to get a single halogen in here with good yield.2157

    OK, but because our conditions now are acid-catalyzed, rather than base-catalyzed, we can't use the enolate; we are going to use the enol instead.2174

    The first two steps are going to be making the enol (remember, we already looked at that mechanism).2183

    It might help to think about what the enol structure looks like; the enol has (instead of a carbonyl) an OH, and then it also has the double bond between what used to be the carbonyl carbon and the α carbon; so that is the enol.2193

    What are the two steps to get there?2207

    Well, first we need to protonate; we will just abbreviate our acetic acid as HA; so step 1 is protonate.2209

    And then, step 2--I need to deprotonate.2223

    This is our tautomerization mechanism; it's just a series of protonations and deprotonations; I'm going to take this α carbon; I'll use the A- that I just had, since it's catalytic in acid, because I use the acid in the first step, and I get it back in the second step.2230

    I form the π bond and move the π bond; so 2 steps--we should always be able to form an enol.2245

    An enol, now, is a nucleophile, just like an enolate.2252

    It is not as easy to see, because we don't have a negative charge; but it is nucleophilic, and it is nucleophilic at the α carbon, just like the enolate was.2255

    So, if we bring in Br2 as our electrophile, notice, it has that leaving group attached to the bromine.2267

    How are we going to get these two together?--well, we are going to react the enol, just like we did the enolate.2274

    What we are going to do is: we are going to start up on this oxygen, this lone pair; we are going to form the carbonyl, and that is going to kick the π bond out, right?2281

    We are forming this bond between the α carbon and the bromine and kicking off our leaving group.2289

    That installs a bromine at the α carbon; this gives me an oxygen; I still have the hydrogen on here; what else do I have?2297

    I have the π bond, and I have just one lone pair left, and a positive charge.2306

    So, I am very close to my product, right?2313

    What do I have to do to get to my product?--I simply have to deprotonate the carbonyl; we can bring A- back in, or we could use the Br- that we just formed; and we can deprotonate.2315

    So, as we will see is common in these reactions, the acid-catalyzed reaction is going to be more steps than the base one.2334

    And we will be using an enol as our nucleophile, instead of an enolate.2344

    But this would be a way that we make...we effectively can do an α halogenation on a ketone or an aldehyde.2350

    We have seen how to add a halide to the α carbon; we have seen how to add an alkyl group to the α carbon; what other electrophiles are there?2359

    Well, the carbonyl, of course, is a big electrophile, and we will study that reaction next; we are going to be spending quite a bit of time, actually, on that reaction.2368

    It is known as the aldol condensation, and it is the reaction of two equivalents of a carbonyl-containing compound, an aldehyde or a ketone.2379

    We'll take a look at an example where it uses base, but it can also be acid-catalyzed; we will see both mechanisms here.2392

    The product looks like this: now, we use two equivalents of the aldehyde, and here is one of them, and then here is the other one.2399

    It is like we had our...if we drew the second acid aldehyde molecule down here, you can see, here is the reaction that is happening.2412

    We are forming a bond between this α carbon and this carbonyl carbon.2422

    OK, we will take a look at that mechanism next.2427

    Now, this product has both an aldehyde component and an alcohol component; so this is described as an aldol product, because it has an aldehyde and has an alcohol.2429

    This is actually one of the few cases in organic chemistry where this is not named after Professor Aldol; this is not a named reaction that is capitalized; it is simply described as an aldol because that is what the product might look like.2442

    OK, and we will also see that, if you heat an aldol product, you can cause it to lose water; so this aldol product will react further upon addition of heat.2456

    It readily loses water to form this carbon-carbon double bond; so we'll look at both of those mechanisms, "How do we get to this aldol product?" and then "How does that aldol product lose water?"2474

    OK, let's look at the base-catalyzed mechanism first: and when we are in base, we are going to deprotonate first--let's ask where would be a good place to deprotonate.2487

    Certainly, it's going to be the α carbon, because that is the theme for this unit; and so, this is not an α carbon; this is not an α proton; this is attached directly to the carbonyl.2499

    That is not at all acidic; but here is my α carbon; here is an α proton; let's change that to a CH2, so we can see one of those hydrogens.2511

    And, absolutely, that is going to be our first step: to deprotonate that α carbon to form an enolate.2518

    Now, every one of these steps is reversible, so we will use our equilibrium arrows here to go from one to the other.2525

    OK, so my first step is to make an enolate, and what kind of reactivity do we expect for an enolate?2535

    Well, it is a nucleophile; so we need to look around for an electrophile.2541

    OK, and this is where it becomes important the choice of base that we use.2548

    We only used hydroxide; we didn't use LDA in this case--we just used hydroxide; hydroxide is a weaker base, so it has taken some molecules of this aldehyde starting material and made the enolate.2552

    But, by and large, most of this aldehyde is still the aldehyde; so the aldehyde is still present.2567

    Therefore, it can serve as our electrophile; the carbonyl can be our electrophile.2575

    So, we let our enolate do its thing: form the π bond; form the carbonyl; kick the π bond out; and attack the carbonyl; and then, what happens when a nucleophile attacks the carbonyl?2582

    We break the π bond, and we move those electrons up.2594

    Let's redraw our enolate part here: we have our carbonyl back; we have a new bond from this carbon to this carbon; this carbon is this carbon; now what do I have on this carbon?2598

    I have an H and a C; I have a hydrogen and a methyl; and I have a single bond O-.2616

    That is a nucleophile attack on an electrophile.2630

    We're not quite done yet: we have an O-; how can we get rid of an O-?2634

    All we need to do is protonate; so we can bring...we just use water; we formed water in this first step, and hydroxide acted as a base; so we could use water as our acid.2637

    We can protonate the O-, and we have our aldol product; here is our aldol product.2652

    Notice, it has a new carbon-carbon bond, because we had a carbon nucleophile attacking a carbon electrophile; so here is the new carbon-carbon bond in the aldol product.2662

    That is going to be important to us, to identify when we try and do synthesis problems.2675

    OK, and overall then in base, it is going to be a three-step mechanism: first, we deprotonate, and then we had attack of the enolate onto the carbonyl, and then we protonate.2681

    Deprotonate, attack, protonate: we are going to see that pattern again and again and again for base-catalyzed mechanisms.2699

    OK, so a summary then: an aldol--what does it mean to be an aldol reaction?2707

    It forms a new carbon-carbon bond between the α carbon of one carbonyl compound (in this case, a ketone or an aldehyde) and a carbonyl carbon of another.2711

    Between the α carbon and the carbonyl carbon, we describe that reaction as the aldol reaction.2722

    Now, we said that this aldol product can lose water; so let's draw the aldol product we have so far.2730

    We said that this, now, can undergo loss of water, and that mechanism is also a two-step mechanism; it is described as a β elimination.2740

    OK, and it starts--the first step is going to be to deprotonate; so I'm going to take that hydroxide again, and I'm going to deprotonate the α carbon, so let's make that a C-H.2753

    We are going to deprotonate the α carbon and make an enolate.2768

    And now, typically, after we have made an enolate, that enolate that we have used thus far on mechanisms--that enolate has always formed the carbonyl and kicked this π bond out to some external electrophile.2779

    But, in this case, what we have is a leaving group that is in the β position.2797

    Remember, the α position is the first carbon next to the carbonyl; the β position is the next one over; and hydroxide can act as a leaving group.2805

    So, when you have a leaving group in the β position, that enolate will re-form the carbonyl, shift this π bond down, and kick the leaving group off.2812

    We are going to deprotonate as our first step; and step 2--we are going to inject the β leaving group.2823

    And, when we do those three arrows, the product we get is the aldol product that we are expecting: the carbon-carbon double bond in between the α and the β carbon.2831

    This is our mechanism: this step here kind of looks like a collapse of a CTI, a little bit.2846

    Remember, collapse of a CTI was when we had an O- kicked down, and on the same carbon, had an OH; it would kick off the OH.2858

    This is an extended system, but it is still the O- kicking down and forcing the OH off.2864

    OK, now think about it: we just lost hydroxide here; that is not a typical leaving group, but we have seen it before for collapse of a CTI; so that is acceptable.2872

    And now, we are seeing that, because this mechanism is similar, it is also acceptable for a β elimination mechanism.2883

    You can lose hydroxide as a leaving group; OK, and remember, the reason for both of these--the reason that it is OK--is that your driving force is your formation of the carbonyl.2888

    In both of those mechanisms, what is pushing the hydroxide out is an O-, which is forming a carbonyl at that same time, so because I am forming this carbonyl, it is OK to lose hydroxide as a leaving group.2907

    OK, just a quick note of caution: this loss of water--this mechanism is not an E2 mechanism.2919

    OK, it is very tempting here (I have redrawn it)--if I wanted to go from this aldol product and eliminate water, what is very tempting is that I just use my base to deprotonate.2928

    And, instead of using it to form an enolate, like I need to, I think, "Well, let's just form this π bond and kick out the leaving group; wouldn't that be a fast, easy mechanism--shouldn't that be better?"2940

    OK, that would be an E2, when we have a single-step elimination mechanism; that is described as E2.2951

    OK, but that does not happen: there is no way we can do an E2, because hydroxide is not an acceptable leaving group for such a mechanism: we have to have a traditional leaving group like bromide, chloride, iodide, tosylate, something like that, in order to enable this.2958

    The only reason this elimination can take place is because of this carbonyl, because you have this resonance-stabilized enolate intermediate, and so it is critical and must be used as part of your mechanism.2975

    OK, so just a reminder not to do a single-step elimination here of water, but to do a two-step β elimination.2985

    OK, so let's summarize the aldol: an aldol is what we have when we have an aldehyde or ketone; we are going to treat it with either base or acid; the ketone (in this case) is going to serve both as the nucleophile (the α carbon is doing the nucleophile), and it is going to serve as the electrophile (the carbonyl of the second molecule is going to be the electrophile, so there is the bond we are forming).2996

    We form a new carbon-carbon bond between the α carbon in one and the carbonyl carbon in the other.3020

    OK, so the product we get could be described as a β hydroxy ketone, right?--not in the α position, but in the β position, where it's going to have this hydroxy group.3027

    And then, if we heat this, we can lose water, and so now we form a double bond between the α carbon and the β carbon; so this structure is described as an α β unsaturated ketone, because we have a point of unsaturation; we have a double bond between the α carbon and the β carbon.3039

    So, when we do an aldol, we can kind of choose which kind of product we want to draw: it's either the β hydroxy ketone, or sometimes it's an α β unsaturated ketone; very often, the trigger on whether or not you are going to lose water will be the addition of heat.3061

    OK, sometimes this is spontaneous, because this dehydration is a relatively easy one.3076

    OK, let's think about why that is: typically, when we dehydrate an alcohol, we need strong conditions: sulfuric acid, phosphoric acid, heat--it's very hard to dehydrate an alcohol.3085

    This one happens very, very easily: you don't need a strong acid; you could even do it in base; and you just need to warm it up a little.3095

    In many cases, it is very, very facile.3103

    OK, but think about your final product: you are not just forming an ordinary carbonyl; it is not just an ordinary alcohol; it is a β-hydroxy alcohol...it is β to a carbonyl, and so this resulting double bond is now going to be conjugated with the initial carbonyls.3106

    This is a conjugated system, and that conjugation--when you have a double bond right next to another double bond, that means you have resonance, and it is a very stable structure.3128

    So, that is why aldol products are very likely to lose water and go to an α-β unsaturated carbonyl.3144

    OK, so so far, we took a look at the base-catalyzed mechanism; we will look at the acid next, but let's draw some comparisons.3155

    In the base-catalyzed mechanism, everything was either...all the species were either neutral, or they had a negative charge; the nucleophile we used was the enolate; the electrophile we used was the ketone carbonyl.3162

    OK, now how is that going to change for an acid-catalyzed mechanism?3182

    Now, an acid-catalyzed mechanism--you can't have a strongly basic species, like an enolate.3185

    You need to have either neutral compounds or positive charges: you are not going to have any O- in an acid.3193

    So, instead of the enolate, what species could we use that would still be nucleophilic?3198

    How about if we protonated that to make it an OH; what would that be called?3204

    That is the enol, and that is going to be the nucleophilic species in the acid-catalyzed.3209

    We also can't have a neutral carbonyl, because if you attack a neutral carbonyl, that forms an O-; you can't have an O- in an acid-catalyzed mechanism, so what we are going to do is: we are also going to protonate the carbonyl, and it will be a protonated carbonyl that gets attacked.3214

    So, it turns out that this mechanism is going to be a little longer, in order to accommodate these species; but let's take a look at that.3232

    We said we had to make an enol; those will be our first two steps of the mechanism, then: we will start with our...we are doing acetone, in this case; and we have some acid present.3244

    So, to make an enol, first we protonate; and then the second step to make the enol is deprotonate; so we take this α proton, A-, and we have an enol.3256

    That has to be our first two steps: to make the enol.3281

    Now, I have my nucleophile: what electrophile is it going to react with?3288

    Well, we just saw on the previous slide: it is not going to react with a neutral carbonyl; it needs to react with a protonated carbonyl.3292

    We just showed the mechanism on how to form the protonated carbonyl, so we can use that again; but this is going to be our electrophile.3300

    What is the bond that we are going to be forming?--it's going to be between this α carbon and this carbonyl carbon, so our mechanism to get there is: our enol starts at the lone pair on the oxygen, forms the carbonyl, and that is what kicks the π bond out.3308

    It kicks those electrons out; those attack the carbonyl of the electrophile and break the π bond; that is the key step in any aldol--when the α carbon attacks the carbonyl carbon.3327

    Let's see where this brings us: let's redraw the enol.3341

    It now has a carbonyl and still has the proton up here; and we just formed the new bond between the α carbon in one and the carbonyl carbon in the other; what does this carbon have on it?3346

    It still has the two methyl groups, and it has a single bond OH.3358

    What do we have to do to finish this up?--it looks like we just have to deprotonate; so we'll bring A- back in here, and we are done.3368

    There is our aldehyde; so once we made our enol, then we protonated the carbonyl; we attacked the carbonyl; and we deprotonated the carbonyl.3385

    OK, but it is going to be a little bit longer mechanism to get where we want to go.3395

    Notice, overall there are no O- charges in the acid; everything is positively charged or neutral--that is going to be consistent with any acid-catalyzed mechanism.3397

    Now, let's think about losing water from that aldol product to form the alpha, beta unsaturated ketone; we describe that mechanism as a beta elimination mechanism; we saw, in base, it was just two steps.3416

    The first step was: we deprotonated to make the enolate.3428

    And then, the second step was: that enolate kicked down, kicked down, and kicked out the leaving group; so eject the beta leaving group.3432

    Now, how do we have to adjust that--who is the beta leaving group?3439

    It was hydroxide in the base-catalyzed.3442

    So, how are we going to adjust this for the acid-catalyzed version?--we can't have an enolate, so instead, we are going to make the enol.3446

    OK, and what do you think about hydroxide--do you think that would be an acceptable leaving group in acidic conditions?3455

    No way--much too strong of a base; so what would be a leaving group that would be OK to have around in an acidic solution?3460

    We would have to lose water; OK, so with that in mind, let's think about our mechanism: let's give it a try.3468

    We are going to start with our aldol product; we want to lose water from this, so the first thing we need to do is: we need to convert this to the enol.3475

    How do we make the enol?--two-step tautomerization mechanism--2 steps.3489

    First, we protonate; that tautomerization practice is really going to pay off when you get to these more complex mechanisms, so that hopefully this part will be somewhat automatic: protonate at the carbonyl, and then deprotonate at the α carbon.3495

    That is the first thing we have to accomplish: we have to make the enol.3520

    OK, and now, we need to get rid of our beta leaving group, but it is not a good leaving group right now.3527

    If this kicked down and kicked off, the leaving group would be hydroxide leaving.3532

    So, how do we make it a better leaving group?--we need to protonate, and so now it is going to look like water when it leaves; it looks like water right now, as it's attached.3535

    This is a good leaving group in acid; so when we said that hydroxide is an OK leaving group for collapse of a CTI for beta elimination, that is true, but that assumes you are looking at a base-catalyzed mechanism, because you have a hydroxide.3554

    In this case, we need water as our leaving group; so now, we are ready to do our beta elimination and eject that beta leaving group.3569

    The same idea as with the enolate, though: we are going to start up here in the lone pair on this oxygen and form the carbonyl; that is what pushes this π bond down; that is what kicks our leaving group off.3577

    All right, we just lost water.3590

    And now, we track our product; see where we are; this, now, is an O+ up here, so we are this close again; we just have one proton to go.3594

    All we need to do is deprotonate: we can bring A- back in.3606

    A-...of course, that is the only negative charge we can have in an acid-catalyzed mechanism: A- represents some very stable conjugate base of a strong acid (like sulfuric acid conjugate base, let's say).3611

    OK, so that would be an OK thing to have in acidic conditions.3624

    A final deprotonation, and we have done our elimination.3631

    So again, it was just two steps in base and several steps in acid; but practice with the base--get used to that; understand the logic, and be able to talk yourself through the mechanism, and know where to go, so that you can make those adjustments and make it work for acid.3634

    So again, it's all positive charges or neutral species.3648

    Now, in all the cases we have looked at so far, aldol has always been a self aldol, meaning one molecule of a ketone has reacted with the exact same structure of another molecule of a ketone.3657

    OK, when we have two different ketones or aldehydes coming together, this is something that can be reasonable, if only one of the compounds has α protons.3670

    So, for example, if we bring it together--acetone and benzaldehyde with base (sodium hydroxide and water), we think about who could be the nucleophile and who could be the electrophile.3681

    Well, we know we have a base here; so we can deprotonate, and we are going to look to our α carbons to deprotonate.3693

    Well, acetone certainly has an α carbon; so this one--when we deprotonate it, that would be our nucleophile.3703

    We have one nucleophile here, but what about benzaldehyde?--there are no α protons on the benzene ring, and this hydrogen is not alpha, so this has no α hydrogens; so that means this cannot be a nucleophile in any way.3708

    It has to be an electrophile.3725

    We only have one nucleophile; how about looking for electrophiles?3728

    Well, both of these structures have carbonyls, so you might think they both could be the electrophile in the reaction.3732

    OK, however, we have a ketone and an aldehyde, and the aldehyde is the better electrophile.3738

    Now, let's just take a quick look at why that is: OK, well, remember: alkyl groups donate electron density; so when we look at a ketone, we know that these carbons are going to be adding electron density to the carbonyl.3750

    That makes the ketone more electron rich.3761

    OK, is that good for an electrophile?--that is not good for an electrophile.3765

    OK, this is more electron rich; so this is a poorer electrophile, and the aldehyde is the better electrophile, because this only has one alkyl group donating; this has a larger partial positive.3770

    So, comparing an aldehyde and a ketone, an aldehyde is going to win, in terms of electrophilicity and reactivity.3784

    And so, comparing acetone and benzaldehyde, benzaldehyde is a better electrophile.3791

    We have one electrophile; we have one nucleophile; which means we can expect to get one major aldol product--and what would that look like?3798

    Well, we could start by drawing our acetone: we know we are going to form a new bond between...this α carbon is our nucleophile, and where is it going to attack?3809

    It is going to attack this benzaldehyde carbonyl; so this used to be a CH3; it is now a CH2, because we deprotonated there, and that is how we have room for this bond.3818

    And then, when we are all done, what do we have on this carbon?--we have a phenyl, we have a hydrogen, and we have an OH.3830

    It would be an O-, but we had protonated at some point, so we get this β-hydroxy ketone; this would be our major product.3837

    However, this probably would lose water spontaneously; we wouldn't really have to warm this up, probably; just having it at room temperature would be enough for this to lose water.3845

    In this case, it is very likely that you would get this as your major product.3860

    OK, and let's think about this particular example: why is it, in this case, that it would be very difficult to isolate this alcohol--very difficult to not have it undergo this dehydration step, this β elimination step?3868

    Well, that is because we have...this double bond is not only in conjugation with the carbonyl, like it always is in an aldol; but we also have this benzene ring right here, so this is conjugated with the benzene ring π bonds, and that makes this π system an extended, conjugated π system--very, very stable.3881

    So, in the case with benzaldehyde, it's very common to seemingly spontaneously lose water and go straight to the alpha, beta unsaturated carbonyl, even though you haven't seen the addition of heat explicitly.3905

    Now, what if I wanted to do a mixed aldol between two ketones or two aldehydes--two groups that have similar reactivities?3923

    Well, we could exert control there; we wouldn't just want to mix those two together in the presence of base, because then, you can get all sorts of possible products out.3931

    You have two possible nucleophiles; you have two possible electrophiles; so in a mixed aldol like that, you might have up to four possible products.3939

    But the way you could exert control is: instead of just mixing everything together, you could do it step-wise by using something like LDA.3947

    Remember, LDA is our strong base; and so, if we started out with just a single ketone, and treated it with LDA, we would expect that ketone to be deprotonated.3954

    Now, this is an interesting case, because we have two different α protons in this case; how would we know which one is the major site of deprotonation?3967

    Well, remember: lithium diisopropylamide had those two isopropyl groups; it is a very bulky base; LDA prefers to attack the less hindered α carbon (and therefore, α proton).3978

    So, it has to do with sterics; it has to do with kinetics; it goes to the less hindered side.3995

    So this is going to deprotonate to give the following enolate: this is a CH2...so we have just one nucleophile; we have this enolate being formed.4001

    Remember, the reason we use LDA--we use a full equivalent of LDA so this gets completely converted to this enolate.4021

    OK, and now, after the enolate is formed, now we add in a second carbonyl; we have just one electrophile, so there is really just one major product that can occur.4028

    What is the bond that we are going to form?--the electrophile has reacted with the carbonyl carbon; the enolate is reactive at the α carbon; and so, we expect the enolate to attack the carbonyl.4039

    And so, what is our product going to look like after workup?4055

    We are going to form a new bond to the α carbon, like we would in any aldol; this carbon is part of the 6-membered ring; and then, on this carbon, we also have a single bond O-, which then gets protonated upon workup.4059

    Now, we would do a separate workup: when our reaction is all done, we get this β-hydroxy carbonyl.4076

    Now, I want to point out just some stuff to you, some common mistakes: it is very common to draw as the product of this, this product; and what would be the problem with drawing this product?4084

    You have attached the carbonyl carbon to the carbonyl carbon; something is missing here.4098

    OK, you have an α-hydroxy carbonyl; that is not the product you should be getting--it should be a β-hydroxy carbonyl.4105

    So, especially when it comes to line drawings, it is very easy to lose carbons when you are drawing your zigs and zags; so make sure you explicitly show your α carbon that was your nucleophile.4111

    There is a new bond to your β carbon, which was your electrophile (that carbonyl carbon).4121

    And that way, you won't make mistakes of accidentally losing carbons when you are dealing with line drawings.4126

    Let's see if we can take one of these problems and do it as a retrosynthesis: if we are given this starting material...this target molecule, rather...and asked to synthesize it, how could we do that?4136

    Can we predict what reagents we need for the aldol to give this target molecule?4149

    Remember, a retrosynthetic arrow asks, "What starting materials do I need?"4156

    "How could I create this target molecule?"4164

    Well, it looks like an aldol product, even if it doesn't give us that clue; it looks like an aldol product, because between the α and the β carbon, we have a double bond.4167

    This is an alpha, beta unsaturated carbonyl (ketone, in this case).4176

    And that is the type of functional group pattern we would get if we did an aldol reaction.4185

    So, it is possible to just kind of disconnect the bonds that we know that are being formed; but I think maybe an easier step backward would be to say, "OK, well, remember: I got this double bond because I lost water from the β-hydroxy ketone."4192

    Maybe you can kind of add water back in; let's abbreviate this as just a phenyl group; let's add water back in, so that we add the hydrogen, and we add OH.4208

    We already had hydrogens here, so we can leave those in if we want, so we don't get too confused.4221

    Let's add water back in to go back to the β-hydroxy ketone, because this is also a pattern that we could get from the aldol reaction, but it's a little easier to grab onto this one, because we have some more interesting functional groups.4225

    OK, the key disconnection we make: remember, what is an aldol?--it is the reaction of an α carbon to a carbonyl carbon.4243

    This is the key disconnection that we make in an aldol; it is between the α and the β carbons.4251

    This carbon--remember, one of these carbons was a nucleophile; one of them was an electrophile; that is how they were able to come together to make this product.4256

    The α carbon, of course, was the nucleophile; this α carbon was the nucleophile--in other words, that was the enolate in the mechanism.4267

    And that means that this carbon was my electrophile; what electrophile could I have that, after it gets attacked, we end up with an alcohol at that carbon?4280

    It was a carbonyl; if I had a carbonyl here, and an enolate attacked it, it would break the π bond, and I would get an alcohol there.4292

    That is the logic we can use: when we do this disconnection, then, we end up with just a phenyl and a 1-carbon aldehyde (it looks like benzaldehyde, again, is involved in this).4302

    That would be our electrophile, and what would our nucleophile be?--it would be a phenyl group with a carbonyl and then a CH3.4313

    So, if I had acetophenone and benzaldehyde, I could actually just mix these two, because this is similar to the mixed aldol we just looked at--because this is a ketone and this is an aldehyde.4328

    I could just mix these two together in the presence of base (sodium hydroxide and water, or methoxide and methanol--something like that), and a little heat to afford the dehydration.4341

    These actually would come together to form this single product as our target molecule, what we expect to get.4352

    This is our major aldol; we wouldn't have to bother first treating this with LDA and then adding the benzaldehyde separately.4359

    OK, but this would be a good process by which we could come up with the starting materials required for an aldol synthesis.4366

    Next, let's take a look at a reaction called the Claisen condensation: this is very much related to the aldol condensation; in fact, it is an aldol reaction; but instead of using a ketone or an aldehyde, we are going to be using an ester instead.4376

    We call that a Claisen.4388

    Let's look at an example of it and see where it takes us.4390

    Let's say we have this ester and we react it with ethoxide, sodium ethoxide, and ethanol; this is a base.4393

    Any time you see hydroxide, alkoxide...you know it is a base.4401

    And then, after that, we are going to do some mild workup; let's see where it brings us, rather than looking at the product first.4404

    What do you think the first step will be of this mechanism?4410

    We have a base, so let's deprotonate something; where do we deprotonate?--α carbon.4415

    α carbon, α carbon, α carbon: that is the whole theme of this lesson.4420

    So, I am going to look: and remember, these carbons are not attached to the carbonyl; those are not α carbons, but this one is; so I could use ethoxide as my base, and I could deprotonate the α carbon.4425

    This is done reversibly, because ethoxide is not LDA--it doesn't do so in just one direction.4439

    But I will get out some of this enolate; let's just abbreviate this--this is an ethyl group here, so we can abbreviate, OEt, and save us a little time drawing it.4448

    OK, so deprotonate to form an enolate: that is a good idea; and what kind of reactivity does an enolate have?4461

    We know that is a nucleophile; so let's look around for potential electrophiles.4468

    Well, remember: because we use this weaker base, ethoxide, we still have most of this ethyl acetate, still as the ester form; so that is still around.4474

    We can bring in another molecule of the ethyl acetate as our electrophile; so see how it is just like an aldol?4486

    We have an enolate of a carbonyl-containing compound attacking a non-deprotonated copy of itself; so our enolate does its thing; re-form the carbonyl; break the π bond.4493

    And then, what happens when you attack a carbonyl?--always, always, always the same: break the π bond and move it up on oxygen.4507

    Let's draw this product over here; let's draw our enolate again--it now has a carbonyl.4516

    Single bond to the α carbon; new carbon-carbon bond here; very good, and then we have...what is on this carbon?...we have a CH3; we have an O-; and we have an O ethoxy--we have an O ethyl.4526

    OK, now if this were an aldol reaction, if we were using aldehydes and ketones, our reaction would be done right now...essentially--almost done.4547

    We deprotonate; we attacked; and then, all we would do is reprotonate; we would have our β-hydroxy ketone product.4554

    OK, however, when you are dealing with an ester, it takes a different path, because what happens when a nucleophile attacks an ester?4562

    You now have an O- on the same carbon as a leaving group; we call this a CTI (a charged tetrahedral intermediate).4571

    So, this is not a stable intermediate: this is not just sit-around-and wait-for-something-to-come-and-protonate-it.4581

    What happens to a CTI?--we use two arrows, and we collapse that CTI.4590

    The lone pair comes down; the leaving group gets kicked off.4597

    And so, our product ends up being this: we kick off ethoxide.4604

    All right, what happens with esters when they get attacked by nucleophiles?--we get addition-elimination; we get a substitution at that carbonyl.4615

    So, taking the place of this ethoxy group is going to be the enolate group.4621

    OK, and it looks like our reaction is done here, because we are at a nice, stable, neutral, happy product; and this is the ultimate product that we will be isolating.4630

    However, in the reaction conditions, this product is not stable, because our reaction conditions are basic.4640

    And what do you see about this product that makes it want to react with base?4648

    We have an active methylene here; we have an active methylene that has two EWGs, two electron withdrawing groups; it has an ester and a ketone attached to it; that makes it very acidic, and because we are in basic conditions, we are going to deprotonate this.4653

    Now, you can draw it, if you like.4680

    We could deprotonate the α carbon.4684

    OK, to make this stabilized enolate, of course, this has lots of resonance; so this is very, very stable; and in fact, this last step--this final deprotonation--is the driving force for the Claisen.4692

    If we did not have this last step--if, for some reason, you didn't have a hydrogen here, and you couldn't deprotonate--the Claisen actually wouldn't go; the retro-Claisen would happen instead.4708

    It is because this final step is essentially irreversible--this is such an acidic proton--that we get this as our final product.4722

    OK, so that is what happens after step 1; and now you can see, perhaps, why we need this step 2: we need to have an acidic workup to reprotonate this enolate that has formed as the final product, and that is how we can get the product that we kind of imagined we were going to get.4732

    We can go back to this neutral intermediate that we had for a fleeting instant, and we come back to our actual Claisen product.4753

    So, how do we describe the Claisen product?--it is described as a β-keto ester.4762

    We have added a new group; we have added a new bond to our α carbon; and the group that we have added is another carbonyl, because we had addition-elimination at that ester group.4770

    We had a substitution there; so that regenerates the carbonyl in the β position, so we get a β-keto ester when we do a Claisen condensation.4781

    Let's take a look at an example and see if we can predict the product here.4794

    OK, we have, in this case...we have a methyl ester; so that is why we are using sodium methoxide and methanol.4798

    Remember, any time we want to have a base around an ester, we want to use that matching base.4804

    And so, what do you think would happen here?--well, I think this base is going to deprotonate our α carbon.4812

    Where do we have an α proton?--right here.4818

    So, I think we are going to have this anion as our nucleophile (I'm just seeing if we can do a little work here, without going through a complete mechanism; let's see if we could come up with the product).4822

    What is that going to react with?--well, there are no other ingredients in here, so this is going to just be a self Claisen condensation; we are going to have another molecule of our ester.4834

    We can draw the carbonyl down here, if you would like, so it's a little easier for it to attack.4848

    I'll bring a second structure in here, and that is our electrophile; our key bond, then--just like the aldol: the α carbon of one to the carbonyl carbon of the next.4856

    But this is going to attack the carbon and break the carbonyl π bond; but then, what is going to happen next?4868

    That O-, in the following step, is going to re-form the carbonyl and kick out the ester.4875

    OK, so it is not an SN2 mechanism; you don't want to just bring the arrow in and show it kicking out--that implies a back side attack; but even if you want to do some of this work in your head, you can imagine it going up into the carbonyl and then coming back down out of the carbonyl and kicking off the leaving group.4881

    OK, and what it does--affect the substitution.4897

    And, after our aqueous workup, our mild workup, we will be able to get to our neutral products; so, can we draw our product, do you think?4902

    Well, let's redraw this enolate part: CH3, CH2, CH; and then our ester group; and so, what we did was: we had to take off one of those α protons so we would have this room here.4909

    This is our new carbon-carbon bond--just a little reminder--just like we have in the aldol.4925

    And then, what is that going to be attached to?--that is going to be attached to this carbonyl, which has a propyl group attached to that CH2, CH2, CH3.4931

    And does that kind of look like the product we would expect?--we get, not α, but β we have a β-keto ester; it is exactly the kind of product we get from a Claisen condensation.4947

    α carbon of one; carbonyl carbon of the other; so if you can see its relationship to the analogous aldol, that is really going to help you work through the Claisen when you need to.4958

    Let's take a look at one last example: what if we had this diester, and it's a diethyl ester, and we treat it with sodium ethoxide, and we just saw what was going to happen?4970

    What product can you get?4983

    OK, well, any time you are reacting something with base, that means we are going to lose a proton; we are going to deprotonate somewhere, and we are going to lose what kind of proton?--we are going to lose an α proton.4984

    We are going to deprotonate the α carbon.4998

    So, this is a symmetrical molecule: it doesn't matter which side we deprotonate; let's deprotonate over here.5001

    We could do that; OK, there is our α carbon--that is our nucleophile; and now, rather than having a second molecule that we can attack, because this has two functional groups, let's see if possibly we can get an intramolecular reaction to take place.5010

    Do we have any electrophile, internally, that is the appropriate distance away?5025

    So, let's check: if this is our first carbon, this is 1, 2, 3, 4, 5 atoms away from a carbonyl which is electrophilic.5031

    Would forming a 5-membered ring be a favorable ring to form?--absolutely: 5- and 6-membered rings are the ones that we are always going to be looking for.5044

    So, what we could do is: we could draw a nice 5-membered ring: 1, 2, 3, 4, 5, and number it: 1, 2, 3, 4, 5, and then just add in our groups on what is missing.5054

    On carbon 1, what do we have?--attached to that is where we have our ethyl ester, because carbon 1 was the α carbon, so it should be α to a carbonyl.5066

    And then, we had a CH2, a CH2, CH2, and then carbon 5 has what?--it has the new bond to carbon 1, of course.5078

    Here we can show it as the bond that we are imagining forming; so it has the new bond to carbon 1, and what else does carbon 5 have?5086

    It has an O ethyl, and it has an O-.5099

    That is what we would get as one of our intermediates, after we deprotonated and attacked.5107

    All right, we can imagine this attacking and breaking the π bond up; and where do we go from here?--well, this looks like a charged tetrahedral intermediate, and so we are going to have this collapse with our two arrows.5113

    Our O- comes down and kicks off our leaving group, and we end up forming a ring that still has that same pattern of a beta-keto ester that we expect for a Claisen.5127

    An intramolecular Claisen condensation has its own name: it is called a Dieckmann reaction; but is the same exact sort of reaction.5142

    Aldol reactions can happen intramolecularly, as well, to form rings, and a Dieckmann is when we have a diester cyclizing to do an aldol-type condensation.5151

    This wraps it up for part 1 of our enols and enolates discussion, and we will continue the discussion, looking at some different types of species, different types of electrophiles, that enols and enolates can react with, next.5163

    Thanks for visiting Educator.com.5180