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Dr. Laurie Starkey

Dr. Laurie Starkey

Alkynes

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
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Lecture Comments (28)

1 answer

Last reply by: Professor Starkey
Sat Aug 25, 2018 7:02 PM

Post by Justine Deacon on August 16 at 08:06:54 PM

Hello, Can I see the 3-D orbital image for an alkyne vs allene, & why is the NMR shifts so different between them?

1 answer

Last reply by: Professor Starkey
Wed Jun 21, 2017 12:38 PM

Post by Sevada Minasian on April 22, 2017

In the first "practice question" for this lecture  that asks for the hydrogenation of the alkyne with lindlars catalyst, the overall product ends up being trans instead of cis when you check the answer. is this a mistake?

1 answer

Last reply by: Professor Starkey
Sun Sep 27, 2015 11:02 AM

Post by Jinhai Zhang on September 26, 2015

Dear Prof. Starkey:
for the addition of HX of alkyne, when we formed the vinyl carbocation, the Br- attacked from the top or from the bottom?  Is there a stereoselective for the vinyl carbocation? Can I think is a syn addition or trans addition of Br from alkyne to alkene

1 answer

Last reply by: Professor Starkey
Sun Sep 27, 2015 11:01 AM

Post by Jinhai Zhang on September 26, 2015

Prof. Starkey:
For the bromination of alkyne, if we add 1 mole of Br2, does the mechanism have the same as alkene that you talked in previous lecture. I can think it is trans addition when we brominate the alkyne to alkene? Thank you for answering.

1 answer

Last reply by: Professor Starkey
Sun Dec 21, 2014 11:22 PM

Post by Parth Shorey on December 21, 2014

At 38:13, Can I use NH2 for the final bond adding to the alkyne? I got it right when you used OH but then for the 2nd Br to break off with an additional bond I used NH2, is that possible?

1 answer

Last reply by: Professor Starkey
Sun Dec 21, 2014 10:09 PM

Post by Parth Shorey on December 21, 2014

I don't understand what is it about peroxide that replaces B ? In hydroboration-oxidation?

1 answer

Last reply by: Professor Starkey
Sat Dec 20, 2014 10:32 PM

Post by Parth Shorey on December 20, 2014

I don't understand when reacting with NaNh3 in the beginning. How you keep giving out H, so it hoes from NH3 to NH2 but then the next H on the trans, where did that come from? I am doing the mechanism and the it doesn't make sense?

1 answer

Last reply by: Professor Starkey
Sun Nov 9, 2014 10:05 PM

Post by Foaad Zaid on November 9, 2014

Hello, for the hydration of an alkyne reaction. Is it safe to say that the acid is H2SO4, that it does all the deprotonating?

2 answers

Last reply by: somia abdelgawad
Wed May 7, 2014 6:24 PM

Post by somia abdelgawad on May 5, 2014

thank you so much. I think to are inspiration to me to be a chemistry teacher one day. you are a great teacher and great help

1 answer

Last reply by: Professor Starkey
Sun Nov 25, 2012 12:13 AM

Post by cheyenne bolanos on November 20, 2012

Hello Dr. Starkey,

I have been doing my homework and in some examples NaNH2 is used as a reagent and in other instances HC(triple bond)C- is used. Could you verify what the difference is?

Thank you,

Cheyenne

2 answers

Last reply by: Jessica Martinez
Sat Nov 3, 2012 10:58 PM

Post by Jessica Martinez on November 2, 2012

Hi Dr. Starkey,

31:25 after you protonated CH2, i think you are missing an "H" it should be CH3COHCH3. I may be wrong

1 answer

Last reply by: Professor Starkey
Wed Dec 28, 2011 11:37 PM

Post by Robert Shaw on December 26, 2011

Could we also use KOH- For the Rx.

1 answer

Last reply by: Professor Starkey
Sun Nov 20, 2011 9:25 AM

Post by Aneseh Ardeshir on November 20, 2011

Dear prof
When we reacting with NaNH2 we suppose to have terminal alkyl, however here we have internal alkyl, I think the second reagent should be koH rather than NaNH2.

Alkynes

Draw the major product(s) formed from this reaction:
Draw the major product(s) formed from this reaction:
Draw the major product(s) formed for each of the reaction:
  • Reduction of Alkynes using Lindlar's Catalyst produces cis alkene:
  • Reduction of Alkynes using Na and NH3 produces trans alkene:
Draw the major product(s) formed from this reaction:
  • This is a dehydrohalogenation reaction.
  • The starting molecule is a geminal dihalide (Two X atoms on the same carbon), which can also undergo dehydrohalogenation similar to vicinal dihalide (Two X atoms on adjacent carbon).
  • The starting molecule will undergo two E2 reactions to form an alkyne.
Draw the major product(s) formed from this reaction:
  • This is a hydration via hydroboration-oxdiation problem
Provide a synthesis for the following reaction:
  • Step 1:
  • Step 2:

*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

Alkynes

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.

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

Transcription: Alkynes

Hello and welcome back to Educator.com.0000

Today we are going to talk about alkynes; an alkyne is a molecule that has a carbon-carbon triple bond in it.0002

We could describe these three bonds connecting the two carbon atoms here as one σ bond and two π bonds.0009

The hybridization of each carbon in this alkyne because it has just two regions of electron density around it--the triple bond and the single bond.0022

We describe it as being sp hybridized; both carbons are sp hybridized.0032

The way that the σ bond is formed is the sp hybrid orbital from one overlaps with the sp hybrid orbital on the other; we describe that as an sp σ bond.0038

Of course, π bonds as usual come about from an overlap of a p orbital with a p orbital and another p orbital with a p orbital.0049

When we try to do a 3D sketch of an alkyne, it tends to get a little messy because we have six electrons here we have to find homes for in a small area; we will get a little practice in that.0058

Let's take a look at a model so maybe you can visualize this before we go to draw it; what we have here is a model of an alkyne; of just acetylene as our simplest alkyne.0071

The two black atoms are the carbons; we just have a single bond out to hydrogen here; notice the geometry of the alkyne with that sp hybridization is linear.0082

We can mention that with our sp--is that it is linear, meaning these bonds are going to be 180 degrees.0094

If you take a look at the π bonds, as usual the p orbitals are going to be perpendicular or orthogonal to each other.0101

With the purple, we have one set of p orbitals; that will be one π bond; that is going to be drawn in the plane of the page, perpendicular to the sp linear.0112

The second set of p orbitals are coming straight out and straight back.0123

If you imagine that the p orbital that was used to hybridize is here along the x-axis, then the π bonds are from the py axes and the pz axes.0127

We can add that little detail if we would like to here--is that we have two aligned p orbitals in the y-axis and two aligned orbitals in the z-axis; we could do that too.0140

When we go to do a sketch, we want to draw the carbon-carbon σ bond as well as the σ bonds going either direction; that is going to be 180 degrees.0151

Then 2hen we draw our p orbitals for our π bonds, we can draw one in the plane very nicely, two lobes of the p orbital.0163

Then we show some interaction with the top and the bottom half there; that represents one π bond; where is the second π bond?0172

The second π bond, that p orbital is going to be coming out and going back; what we could do is just maybe twist the molecule a little bit to the side so we can see both halves.0180

Maybe we can draw one as a wedge and one as a dash, one as a wedge and one as a dash; then try and show some connectivity between these front halves and these back halves.0189

Again, the larger you draw your 3D sketch, the better chance you have of having enough room to show everything.0200

Maybe we could show the bond angle over here since it is a little less messy; we can say that it is 180 degrees.0208

We want to note that our p orbitals are perpendicular to the sp linear line; that is what we are showing in our 3D sketch.0214

So really, an alkyne is a linear molecule; you can see that you have as a cylinder electron density around the carbon-carbon σ bond; that is what a triple bond looks like.0223

A triple bond has room for bonding on either end; it has two things that are going to be attached to it.0237

One other bit of terminology we are going to use to describe alkynes, we are going to describe them as being internal if there is a carbon group on either side of the triple bond.0244

In other words, the triple bond is within a carbon chain; we are going to describe it as terminal if it is at the end of the carbon chain.0253

What makes a terminal alkyne unique is that it has a hydrogen attached to the triple bond carbon; we are going to see some unique reactivity for that.0261

We will see some reactions that are good for all alkynes; then we are going to see some reactions that are specific just to terminal alkynes.0269

One of the reactions we can do for an alkyne is we could do a reduction; if we do catalytic hydrogenation much like we did for alkenes.0279

In other words, we react with hydrogen gas and some kind of catalyst like palladium or platinum, something like that typically.0286

If we have an excess amount of the hydrogen gas available, then what we expect to happen is much like we did for the alkene.0293

We break one π bond and we add a hydrogen to each carbon; then we are going to break the second π bond and do the exact same thing.0303

If we do an exhaustive hydrogenation like this, we can convert an alkyne to an alkane; you would end up adding two equivalents of your hydrogen gas.0313

However if we used a different kind of catalyst, if we still had plenty of hydrogen around.0326

But instead of just using palladium, we use this combination of palladium with some kind of salt, like barium sulfate or calcium carbonate, and quinoline.0333

The molecule of quinoline is here; it has two aromatic rings with a nitrogen replacing one of the carbons.0341

This combination is known as Lindlar catalyst or Lindlar's catalyst sometimes; sometimes you might see all these ingredients listed out or sometimes you might just see it referred to as Lindlar catalyst.0347

This is described as a poison catalyst; what happens with a poison catalyst is that there is no reaction with alkenes.0361

We are going to only partially reduce the carbon-carbon triple bond; we are going to add one equivalent of hydrogen; but then we are going to stop at that point.0376

Remember the mechanism for the catalytic hydrogenation; the metal is going to absorb the hydrogen; the metal is going to grab onto the alkene or alkyne in this case.0387

It is going to deliver both of those hydrogens to the same face of the π bond.0397

We are going to be able to observe that in this case because the two hydrogen that are added are going to be added to the same face.0402

We are going to get... I forgot there was a prime here... we are going to get a cis alkene as our product when we do a poison catalytic hydrogenation; a cis alkene.0411

Up here when we added two equivalents, yes those hydrogens were added in a syn fashion.0423

But because each carbon received two hydrogens, we didn't have any stereocenter there; so there is no way to observe that stereochemistry.0429

There is no stereochemistry to show here; but here we want to be sure to very carefully draw the cis stereochemistry when we add a single equivalent of H2.0435

There is one additional reduction reaction we can do for alkynes; that is called dissolving metal reduction--that is when we use either sodium metal or lithium metal in ammonia.0446

Ammonia is being used here as our solvent; it is also part of the mechanism; it is a proton source in the mechanism.0457

What happens in this case is we reduce the alkyne partially and we get the trans alkene as our product.0466

I am not going to go through a mechanism for this; that is something that you can find in a textbook or some other resource.0480

But just to give you an understanding of what is going on in this mechanism--is we are using sodium metal; this is sodium metal, lithium metal; it is not the cation.0489

Each of those metals has a single electron in its valence shell, very readily loses that single electron, makes a great reducing agent because it donates that electron to someone else.0498

The alkyne is accepting that electron, getting reduced; what is happening is our Na0 is going to Na+ after it donates the electrons.0508

The sodium is getting oxidized as the alkyne is getting reduced; this is a redox reaction like we have seen for electron transfer reactions.0521

What is important to note here is that, as opposed to the Lindlar catalyst, we are going to get the opposite stereochemistry.0532

We are going to get the trans alkene; that is due to the stability of the intermediate that is formed in this reaction.0539

A lot of different options for reducing an alkyne; you can do it completely to an alkane; or you can do it either to the cis or trans alkene.0549

When it comes to synthesis problems, we have a lot of variability, a lot of versatility, with an alkyne starting material.0557

We just talked about reductions of alkynes because we were increasing the number of C-H bonds; oxidations of alkynes means we are increasing the number of C-O bonds.0567

There is a few different ones; the one that you will see most often is this one--it is called ozonolysis.0577

When we react with ozone, just like we did for an alkene, we are going to completely cleave this carbon-carbon triple bond.0585

Because we have three carbon-carbon bonds that we are breaking, this is an oxidation; we are going to be replacing those three with carbon-oxygen bonds.0595

How do we a draw a carbon with three bonds to oxygen?--we are going to make one a carbonyl just like we did for ozonolysis of an alkene.0607

We replace the double bond with a carbonyl, C-O double bond; then we are going to add a third bond to oxygen which will result as an OH group.0616

We are going to convert all three carbon-carbon bonds to three oxygen bonds; that is going to happen on both sides of the triple bond.0627

The functional group we make in this reaction is a carboxylic acid; so oxidation of an alkyne would be a way to make a carboxylic acid functional group.0637

You are also cleaving your carbon chain; you are going to be losing some of your carbons and getting a carboxylic acid as a result.0649

Most of the reactions that we are going to be studying in this unit involve addition reactions; again similar to alkenes where we break the π bond and we add groups to either carbon.0659

One example of such a reaction is the bromination of an alkyne; if we used Br2 and we had an excess amount of Br2, what do you think might happen?0669

I am thinking we are going to break the carbon-carbon triple bond, break one of the π bonds, and add a bromine and a bromine.0682

Then we are going to break the second π bond; we are going to add a bromine and a bromine as well.0690

That is exactly what happens; it adds two equivalents of the Br2; both π bonds react just like the single π bond in an alkene.0695

What is nice about this reaction is that there is no regiochemistry to consider; in other words, since we are adding a bromine and a bromine, we don't have to decide who goes where.0705

There is really only one place to put them; there is also no stereochemistry to be concerned with in this reaction.0714

We know that bromination occurs with anti addition because of that bromonium ion intermediate.0720

But because we end up adding two bromines to each carbon, again there is no chiral centers; so there is no way to observe that anti addition.0725

This ends up being one of the simplest products to predict because it is almost impossible to get it wrong; all we do is break the π bonds and add four bromines.0733

It is a little more interesting when we add HBr across a triple bond because now we are adding two different groups and we have to decide where does the hydrogen go, where does the bromine go.0746

Remember we learned about Markovnikov's rule for alkenes; it turns out Markovnikov's rule holds for alkynes as well.0756

Just as you might predict from what you know for alkenes, we are going to break the π bond; we are going to add a group to either carbon.0767

We are going to add the hydrogen to the carbon with more hydrogens; that is what Markonikov's rule tells us; we are going to the hydrogen to this end carbon and the bromine to the middle carbon.0776

It turns out that the second equivalent of HBr that adds follows the exact same regiochemistry.0788

We are going to break the second π bond, add a group to each carbon; hydrogen again goes to the end carbon and the bromine goes to the middle carbon.0793

It is essentially the same mechanism as the alkene; but let's go through that because it is a little interesting.0801

After we add our first HBr, we want to think about the influence that might have when we go to add the second equivalent of HBr; let's take a look at that mechanism.0807

It is going to start with the reaction of the alkyne with HBr as a strong acid; we are going to start by protonating the π bond.0819

This is an acid; the alkyne, any alkene or alkyne around, any double bond is going to act as a base--is going to get protonated.0830

This the point at which we decide our regiochemistry; we are going to want to put the hydrogen on the end carbon so that our carbocation goes on the more substituted carbon, the more stable carbocation.0841

This is as usual the foundation for Markovnikov's rule and the foundation for our regiochemistry determination--is we want to go through the lowest energy intermediate possible.0857

This is interesting; it is called a vinyl carbocation; we have never seen one of these before--having a positive charge on a triple bond; but it can happen; it will happen.0866

What happens from this point forward?--we just made Br- in this first step; that is going to act as a nucleophile; it is going to add to the carbocation.0879

We are going to have... after this, we will have added our first equivalent of HBr following Markovnikov's rule as we expect; but let's think about this second equivalent.0892

If we assume that the second protonation occurs with the same regiochemistry, that is going to yes put the positive charge on the more substituted carbon.0904

But that carbon... it is secondary versus primary; but that carbon also has a bromine attached to it; we can't just assume that that bromine is not going to have an influence.0921

We need to consider that to see if this still is the better carbocation or maybe the carbocation wants to be on the other carbon away from the bromine.0932

We need to ask: is the bromine good or bad for the carbocation, for the positive charge?--is that a stabilizing thing to have the bromine or is it destabilizing?0939

You might think bromine is more electronegative than carbon so bromine is pulling some electron density away; that is not a good thing for a carbocation.0953

It is already electron deficient; pulling electron density would make it less stable; that would not be good; but take a look at what else bromine has.0960

Bromine has lone pairs; that is a source of electron density; what can happen is these lone pairs can actually be shared, can donate to the carbocation and offer some resonance stabilization.0968

It turns out that yes the carbocation chooses to go here; in fact it is going to be stabilized by that bromine by resonance; it is resonance stabilized.0985

I just wanted to point that out and have you think about that; if you ever had a mechanism with a carbocation and you have a heteroatom like this--a bromine with a lone pair.0999

It is something that could be an electron donating group; it could stabilize the positive charge; that would be a good thing.1009

That is just a little note here for our resonance; let's redraw our first form so we are not making too much of a mess here.1021

We have this carbocation now; after our second protonation, what do we do to finish up our mechanism?1028

We simply attack with our second equivalent of bromide, Br-; and our mechanism is done.1034

Ultimately it is the same mechanism as the addition of HBr to an alkene; we just do it twice; protonate and attack.1043

Then protonate again with the same regiochemistry, the same Markovnikov regiochemistry, to give the more stable carbocation; and then attack.1051

Let's take a break for a second and see if we can do a transform problem beginning with an alkyne starting material and some of the reactions we have seen; we know about alkynes.1061

Let's say we wanted to get to this product; we have gotten rid of the triple bond; the two bromines are new; but there is something else that is new in this product; what do we have?1070

One π bond is gone; the other π bond is also gone though; so there is also two new hydrogens in this molecule that need to get added in throughout the course of our synthesis.1085

How about if I just used... I need to add an H and a Br, an H and a Br; so how about if I added HBr?--an excess of HBr?--would that give me my product that I'm expecting?1101

That would break both π bonds and it would add HBr twice; but where would the location of those bromines be?--they would not be on opposite carbons; they would be on the same carbon.1113

Remember we get Markovnikov addition of both equivalents; the hydrogens both go to one carbon; the bromines both go to the other carbon; that would give the wrong regiochemistry.1123

What reaction have we seen that puts a bromine on one carbon and another bromine on the carbon next to it?--what did you need to add to... what reaction have we seen that does that?1132

How about the bromination reaction of an alkene?--if we think about a retrosynthesis of this, in other words, what starting materials do I need to plan this synthesis?1143

If I want two bromines, then I need to have a double bond; if I had a double bond in this position, then I would be able to add Br2 to that; I would now have two bromines.1159

That is good; I know I need to get to the alkene; but the second question we have is how about the stereochemistry?1177

If I were to have this alkene and add Br2, what do we know about the stereochemistry of that bromination reaction?1184

Remember the first bromine comes in to make the bromonium ion; then the second bromine comes in to open that up; we get anti addition because of that backside attack, that Sn2.1193

If these methyl groups were on the same side like they are here, would you get the two bromines adding from the same face?--that would not give us the right product.1206

Something is wrong here; the stereochemistry of our alkene is wrong; maybe we can... another way to look at this is we can rotate this.1216

And say: I know that bromination occurs anti so let me look at the product in a slightly different way where the bromines are drawn anti--they are drawn one up and one down.1228

In other words, if I just rotate this... I just did that backwards, excuse me... when I rotate this bond, if I just turn around here and bring that bromine down.1243

Then what happens to my methyl group?--it was a wedge; when I rotate it 180 degrees, now it is going to be a dash.1256

If we look at it from this point of view, now when we think about what starting material do I need to do the bromination, what is the actual relationship that we need between those methyl groups?1269

One is back and one is forward; they need to be trans to each other in order to get the proper stereochemistry in the product.1281

We can confirm that; if I had this alkene with the trans methyls and I brominated, add a bromine, one to the top and one to the bottom, yes I would get this product out.1293

This is now... now we have solved our problem as to how we are going to get there; what we need to do to our alkyne is first convert it to the trans alkene.1304

Then we can take that trans alkene and add the bromine to it; the second part is just simply Br2; we will add the bromines trans.1319

How do we go from an alkyne to a trans alkene?--it looks like we have done some kind of reduction; we have added hydrogens to the carbons.1332

Catalytic hydrogenation would totally get rid of the triple bond; poison catalytic hydrogenation adds the hydrogens to the same face; it would give the cis double bond.1344

How do we get the trans?--that is the dissolving metal reduction; sodium metal and ammonia solvent, NaNH3, is dissolving metal; that reduces it to give the trans alkene.1355

Then bromination gives the final product; so we need to think about regiochemistry; we need to think about stereochemistry when we propose a synthesis.1368

We have to check every step of the way, is this actually the product, the product we are expecting?--is that actually the product that would be formed?1377

One quick thing I want to mention about these reagents--Na and NH3 is not the same as NaNH2; that is another reagent we are going to be seeing shortly.1383

NaNH2 is a salt; it means we have Na+NH2-; that is a completely different reagent than having sodium metal and NH3 solvent.1394

You could list them separately or make sure you put a comma between them; you don't want to squeeze them together and confuse it with NaNH2.1408

What else can we add to a triple bond?--we have seen adding hydrogens; we have seen adding bromines; we have seen adding a hydrogen and a bromine.1417

How about if we wanted to do a hydration of an alkyne?--that means we are going to be adding an H and an OH; we are going to add the components of water.1426

What do you think might happen based on what we know about the addition of HBr?--I think I am going to break the π bond; let's just do this one at a time.1436

I am going to break the π bond; I am going to add a group to each carbon; where do you think the hydrogen should go of H2O?1445

If it has a mechanism similar to all the other addition reactions, then I expect the hydrogen to go to the carbon with more hydrogens so that it follows Markovnikov's rule.1452

This in fact is what happens; but this is not a final product; you might think it is going to continue and we will do a second addition.1463

If it were exactly analogous to addition of HBr, we would add one equivalent; then we would add a second equivalent; and we would be done.1474

The problem is that this functional group, having two OHs attached to the same carbon, is extremely unstable; that is a very very rare arrangement of functional groups.1482

This is not the product that is observed; what happens instead is we add a single equivalent of water; this product is described as an enol.1497

It is called an enol because it has both an alkene, a carbon-carbon double bond, and an alcohol on the same carbon; one carbon has both the double bond and the OH.1509

It is no longer an alkene; it is no longer a simple alcohol; it is called an enol.1521

Enols do something very special; they will undergo a process called tautomerization; this will tautomerize... tautomerize... I thought I spelled it wrong, sorry.1526

What is going to happen is it is going to rearrange; instead of having an enol, we have a carbonyl; we are going to get a ketone as our product.1548

This is actually called a keto-enol tautomerization; we will take a look at that mechanism; it is a two-step mechanism; let's look at the mechanism for the complete process.1560

You will notice in our reaction conditions, we have water as you might expect; we have acid as we also typically have for hydration; it is an acid-catalyzed mechanism.1578

We have this last guy--mercuric sulfate is usually thrown in here; this is simply a catalyst... and this is a catalyst.1588

If you... you might be able to do a mechanism using that catalyst; but let's just take a look at a simple mechanism where we don't use that catalyst.1598

What do you think our first step will be for a mechanism in these reaction conditions?--clearly we have acidic conditions.1610

Anytime we have an acid and we have a π bond, a good first step is to protonate the π bond; let's just use a J to represent an acid.1620

We will protonate the π bond; we are going to do that with Markovnikov regiochemistry to give this more stable secondary vinyl carbocation rather than a primary carbocation.1631

What could we do next?--we look around for a nucleophile to add in; we have water as our solvent most likely; but that is the best nucleophile we have around.1647

So water is going to attack the carbocation... I will just condense this to be a CH2 here.1661

What do we still have on this oxygen?--it still has the two hydrogens and still has one lone pair of electrons; the other lone pair is right here now being shared.1672

This looks like it is charged; one, two, three, four, five; one, two, three, four, five; oxygen wants six; it has five; this is an O+.1683

We do the same mechanism we had for HBr; we protonate and then we attack; but because water is a neutral nucleophile, after we attack, we have a charged species.1692

We need to get rid of that charge; the way we do that is the usual; we deprotonate the oxygen; we remove one of these protons.1701

Let's bring in A- again, grab the proton, leave the electrons behind; and we are done with our addition, our first addition.1711

We are here; this is where we are--at the enol; now we need to go to the... we are going to want to go to the ketone.1725

This is going to... I think it helps to think about the rest of this mechanism by drawing the product that we know that we get; we don't get the enol; we get a carbonyl where the enol carbon was.1739

Let's draw that product out; there is our product; now by seeing where we are going, we can think more carefully about how we get there.1751

If you compare the structure of this enol to the structure of the ketone, we know we have to do this tautomerization mechanism; what changes do we have to accomplish?--what differences are there?1763

The π bond moves; but that is part of our mechanism; that is part of the resonance in our mechanism; but here we have an OH; now we have just an oxygen; we have to remove that H+.1774

The way we could describe that is we have to deprotonate here; that is one of the things we need to accomplish; we need to deprotonate that oxygen.1788

What other change is taking place?--this double bond carbon used to be just a CH2; now he is a single bond; he is a CH3.1796

How would you describe what has to happen here on that carbon?--I have to protonate here; that is it; those are our two steps for our tautomerization.1805

It is a two-step mechanism; it is simply protonations and deprotonations--are what describe any tautomerization process.1819

The only thing we have to decide is what should we do first?--what should be our first step, a deprotonation or a protonation?1828

How about we consider our reaction conditions; we are still in our acidic reaction conditions; we are here at a neutral molecule; where do we go from this point?1834

Let's protonate something; let's use our acid; let's protonate; this is going to be step one is protonate; and step two is deprotonate.1843

I will bring in HA again... let's just think about this for a second; how is it that I can protonate this carbon; it doesn't have a lone pair of electrons; how can I protonate it?1852

I can use the π bond attached to it; what we are going to do is we are going to protonate this π bond as a way to put the hydrogen on the carbon.1864

That is step one--is we are going to protonate that CH2; now let's think about going from here to here; this is step two; we need to deprotonate.1881

Can you think about what our deprotonation mechanism is going to look like?--I am going to grab this proton; where am I going to put these two electrons?1892

Rather than put them on this oxygen and have an O- and a C+, all I need to do is bring those two electrons down to be a π bond.1902

There we go; we have our carbonyl; we have our ketone product; we have our carbonyl product; this is called a tautomerization.1911

We are going to be seeing lots more tautomerizations down the road when we are studying carbonyl compounds and the mechanisms they undergo; but this is our first example of it.1918

Where we are going to see it is in the case of hydrating an alkyne; what we do is we add just a single equivalent of H and OH.1928

Then that resulting enol, we have to get used to converting an enol structure to a ketone structure, a carbonyl structure.1939

The carbon that used to have both the OH and the double bond is now a carbonyl; the carbon that used to be part of the double bond will have a new extra proton.1947

That is how we get our ketone structure out; if we use water and acid, we are going to get our Markovnikov addition as usual.1957

Remember when we did hydration of alkenes, we had a few different mechanisms that we could do, a few different reaction conditions we could do; for alkynes, we have those options as well.1967

If you recall the process of hydroboration-oxidation, that was another way that we could add water across a π bond.1979

But this is the one that did it with anti-Markovnikov regiochemistry; this is the one that was complementary to the others and did the opposite.1987

We are going to do the same... we could do the same thing for an alkyne; if we have a terminal alkyne, we can do this reaction and get a specific regiochemistry.1996

This guy is called disiamylborane; it has two bulky siamyl groups attached to the boron; but like every boron reagent, the most important thing is that it has a boron and it has a hydrogen.2009

The reaction that it does is called hydroboration; in a single step it adds the hydrogen and the boron; that helps explain the regiochemistry.2025

The regiochemistry that we see is that we add the hydrogen to the internal carbon and we add the boron to the terminal carbon.2035

I say this has to be a terminal alkyne because if the triple bond has a carbon group on either side, then you are not going to get a fixed regiochemistry because there is no significant difference between the two carbons.2045

But if there is a hydrogen here and an alkyl group here, then the boron clearly goes to the less hindered carbon; we will get this anti-Markovnikov regiochemistry.2056

The second step of this process is typically the oxidation; we treat it with an oxidizing agent like hydrogen peroxide; what happens is this boron gets converted to an OH group.2066

We are going to break the π bond and add just a single equivalent of water; we are going to do it in anti-Markovnikov regiochemistry.2081

The hydrogen goes to the carbon on the inside; the OH goes to the carbon on the outside; what do you think happens next?2090

Are we going to add a second equivalent of water?--or can this structure do something else that is going to be more favorable?2099

Once again, every time we add H2O across a π bond or the components of water across a π bond, we are going to end up with an enol intermediate.2107

That is going to not be our final product and not react further to add the π bond.2117

Instead it is going to undergo a rearrangement which is an equilibrium but highly favored in the forward direction where we have, instead of an enol, we have a carbonyl.2125

This carbon becomes a carbonyl; this carbon gets an extra hydrogen.2136

When we do hydroboration-oxidation on a terminal alkyne, the oxygen goes to the end carbon; the product we get here is an aldehyde.2147

When you have a carbonyl at the end of a carbon chain so there is a hydrogen attached to that carbonyl, we call that an aldehyde rather than a ketone.2156

We still call this a tautomerization; but sometimes the enol might go to a ketone; sometimes it might go to an aldehyde depending on what other groups are attached to the enol carbons.2163

Let's think about some syntheses we can do; if we wanted to make an alkyne, how could we do that?2180

We have already talked about the reactions that alkynes can undergo; but if we wanted to create a triple bond, where could it come from?2187

We have two good ways to make an alkyne target molecule; one option is to do a dehydrohalogenation; what does that mean?--it means we lose H and a Br; we do a dehydrohalogenation.2193

If we start with a carbon chain with two bromines here and two hydrogens here and we treat it with some really strong base like KOH or NaNH2.2211

Very strong base, we have NH2-; we have hydroxide; you should recognize both of those as very strong bases.2224

We add heat here; these are perfect conditions to do an elimination reaction; do you think this is going to be an E1 elimination mechanism or an E2 elimination mechanism?2231

We have a really strong base so I am thinking it is going to be an E2; it is going to end up doing this twice; we can show our first equivalent of base; let's just use the hydroxide.2243

We could show the mechanism; he E2 is a one-step mechanism where our strong base attacks a β hydrogen, forms a π bond, kicks off the leaving group.2257

We do anti elimination; we haven't really shown stereochemistry here; but you could maybe see the stereochemistry up to this point.2271

But again typically we don't stop here; we have heat; we do more vigorous conditions; we need a really strong base to do this double elimination; we are going to a second elimination.2278

Even though this is harder, but we can have the hydroxide or the NH2- come in and grab and even eliminate a vinyl bromide; we get a vinyl bromide intermediate here.2297

Up to now, we have never seen an E2 elimination occur when a leaving group is already on a double bond; but in fact you can force those conditions and you will be able to form a triple bond.2312

We are losing HBr times 2; we call this a dehydrohalogenation reaction; just like we can use an E2 to form an alkene, if we have two leaving groups, we can use an E2 elimination to form an alkyne.2328

Let's see if we can apply this strategy to the following alkyne synthesis; if I had this alkene, how could I convert it to this alkyne?2349

Once again we really should be thinking about these retrosynthetically and plan our synthesis first; let's look at our product and say what starting materials do I need?2362

What structure could I have started with that I know I can convert into this target molecule, into this alkyne?--what did we just learn?2373

We said if there were two leaving groups, if we had a bromine on each carbon like this, then that would work as an elimination; if I had this, I would be able to do a double E2 to get the triple bond.2383

I look at where I want to be; then I look at where I am starting and say how can I get from the double bond to the intermediate structure that has the two leaving groups?2408

All I have done is I have removed the π bond and replaced it with a bromine and a bromine; what reagent will do that?--all we need to do is add Br2.2421

It doesn't really matter what our stereochemistry is at this point; because once we do our double elimination, all the stereochemistry is gone; we are left with a linear molecule.2435

In this kind of synthesis, it doesn't matter whether you get one stereochemistry or another; that is not a concern in this case.2443

But we could add the two bromines; then we could add some strong base like NaNH2 and heat.2451

It is a real good idea to put that heat in there because we definitely need vigorous condition; that always favors the elimination; but in this case, it definitely favors the double elimination.2458

Then we can do our alkyne synthesis; so one route to creating a triple bond is by having two leaving groups in a position that can do a double elimination.2468

A more common way to synthesize an alkyne is to start with a triple bond already in place but then to functionalize it--to add groups on either side of the triple bond.2483

What we are going to be using is if we had this kind of an intermediate with a negative charge on that carbon, then we could use that as a substrate to make different alkyne products.2494

How do we get a negative charge on a carbon?--what we are going to do is we need to deprotonate that carbon; let's talk a little bit about the potential acidity of an alkyne.2511

How willing would an alkyne be to lose its proton to make this anion?--what I would like to do is I would like to compare an alkyne to an alkene to an alkane.2522

Let's look at these three different types of CHs and think about how easy or how difficult it is to deprotonate them.2533

I have shown you their pKa's; alkyne has a pKa somewhere around 26, an alkene about 36, an alkane about 49; again huge differences in their numbers here because these are orders of magnitude.2540

Who is the strongest acid here with these three numbers--26, 36, 49?--what is the relationship between pKa and acidity?--the lower the pKa, the higher the acidity.2555

This number of 26, this is the most acidic; it is ten to the ten times more acidic than an alkene; the alkane is by far the least acidic.2567

How can we justify that?--how can we explain that?--as usual what we want to do is we want to look at the conjugate bases.2588

In other words, let each of these acids be an acid; let them donate a proton; let's see what we end up with after that happens.2594

In other words, let's have some base come in and remove this proton; where I used to have a hydrogen, now I have a lone pair and a negative charge.2604

I can do that for the alkyne and the alkene and the alkane; this is a C- versus a C- versus a C-.2614

There is no periodic trends we are looking at here; there is no difference in electronegativity of these atoms; but the difference we do have is the hybridization of those carbons.2620

We can see that the alkyne is an sp hybridized, the alkene is sp2, and the alkane is sp3; we have another way to describe these hybridized orbitals.2632

We could say that the sp orbital... because in order to make an sp hybrid orbital, we took an s orbital and a p orbital and mixed them together.2651

The new hybrid orbital has--50% of its character is like an s orbital and 50% of its character is like a p orbital; we describe an sp hybridized carbon as having 50% s character; it is 50% s-like.2659

How about an sp2 hybridized orbital; how did we get an sp2?--we took one s orbital and two p orbitals.2676

Of the three total orbitals only one of them is s; so one-third, we describe an sp2 as having 33% s character.2683

An sp3, we have one, two, three, four hybrid orbitals, only one of which is an s; this is described as having 25% s character.2695

That is this hybridization difference in this s character difference is going to be the difference here; let's remind ourselves the difference between an s orbital and a p orbital.2706

If we take a look at the energy of these various orbitals, an s orbital is lower in energy than a p orbital.2721

Remember a p orbital is further away from the nucleus; it has a node in it so it is a higher energy orbital.2729

Where do you think the energy in sp hybrid orbital is?--it is going to be right in between; because it has 50% character of an s and 50% of a p.2734

How about an sp2?--that is going to be maybe two-thirds of the way up; it is going to be a little closer to the p orbital; and sp3 even closer still.2743

These different hybrid orbitals are of different energies; when you in this case have this negative charge in an sp hybrid orbital, that is a lower energy orbital.2754

That means it is going to be more stable; let's state the facts here; let's describe this; the lone pair and the negative charge is in a lower energy sp orbital.2767

That means that it is a more stable anion; let's stabilize the negative charge by putting that electron density in a lower energy orbital.2794

If you are more stable, what does that mean for your reactivity?--more stable means you are less reactive; this anion is the least reactive; therefore it is the weakest conjugate base.2806

Because he is more stable, he is less reactive; that makes him a weaker conjugate base than the others.2828

If something has a very weak conjugate base, what does that say about the parent?--we have that inverse relationship; this has the strongest parent acid.2835

Is that what the pKa data tell us?--is that confirmed by the pKa?--sure, that had the lowest pKa; so we knew that the alkyne going into this was the most acidic.2848

This explains why; the negative charge doesn't mind being in sp hybridized orbital because it is relatively low energy.2857

We compare that to this sp3 hybridized carbon with a negative charge; this has no stabilization; it has nothing good about it.2864

It is on a carbon; carbon doesn't like having a negative charge; it is on a sp3 hybridized carbon, the highest energy orbital we can have.2877

That makes him, because he is very unstable, that makes him the most reactive and therefore the strongest conjugate base.2886

What do we know about something that has a very strong reactive conjugate base?--it must be a weak parent acid; this has the weakest parent acid.2901

When we look at an alkyne versus an alkene and an alkane, which one is it reasonable to deprotonate?--only the alkyne.2917

What we are seeing here is that alkynes can be deprotonated... alkynes can be deprotonated.2926

They are acidic; they are acidic terminal alkynes, assuming you have a hydrogen attached to the triple bond.2936

Alkenes and alkanes, what do we makes of these numbers like 36 and 49?--that means never; we are not ever going to deprotonate an alkene or alkyne.2945

We are never going to deprotonate an alkene or an alkyne; we are just not going to ever see any cases.2958

There is no base strong enough to remove that proton; that is never going to be a favorable reaction.2962

Again this is something we are going to be seeing a lot in the upcoming chapters--is when can we deprotonate?--when can we not?--who is the stronger acid and why?2970

An alkyne, what is unique about a terminal alkyne is it is one of those few carbon groups that can be deprotonated; normally carbon doesn't like having a negative charge; so this is pretty special.2979

I mentioned that we need some base here to come in and deprotonate it; let's think about what base we can use.2990

We are going to need some very strong base; very strong base meaning not something like NaOH; hydroxide is a strong base; but it is all relative.3000

It is not a strong enough base to deprotonate an alkyne; that would form water in this reaction; that is not going to be as stable as having just the neutral alkyne and hydroxide.3013

Instead we are going to use a stronger base like NaNH2; this guy is called sodium amide; it is NH2- is what we have here; this is ionic.3027

A nitrogen doesn't handle a negative charge as well as an oxygen; this is a more reactive anion; this is a stronger base than hydroxide would be.3042

This could and will deprotonate the alkyne--a lone pair and negative charge; we would have the sodium salt here; if we use sodium amide, we have the sodium salt.3052

Anytime there is an anion, there is always a cation; sometimes we draw it; sometimes we don't.3068

What would the other product be here?--if NH2- was our base, when we protonated that, we would get out ammonia, NH3.3072

I want to point this out because remember any proton transfer is always a fight between two acids trying to give up their protons, two bases trying to take the protons.3081

We need to consider this reverse reaction if we are going to determine whether or not this is going to be favorable.3090

In the forward reaction, we have alkyne as our acid; in the reverse reaction, it would be ammonia as our acid; ammonia has a pKa of about 36.3097

Compared to 26 and 36, who is the stronger acid?--the alkyne is a much stronger acid; the ammonia is a weaker acid.3109

When we take a look at this equilibrium, what direction does it lie?--it always lies in the direction of the weaker acid; in other words, the strong acid and the strong base; this is a very strong base.3121

The strong acid and the strong base are going to react; they are going to transfer their proton and give the products which are more stable.3135

This equilibrium is really a one-way street; the reverse reaction is negligible; so this would be an excellent base if we ever wanted to fully deprotonate an alkyne.3143

What are we going to do with this?--before we move to the next slide, let's take a look at this.3160

What we are saying then is that this is pretty stable; this is relatively stable; this is reasonable to make; this is an anion that we can make; we are going to want to use it.3166

What use do you think you might have for a carbon with a lone pair and a negative charge?--what kind of behavior might that have?3175

Do you think maybe a nucleophile or an electrophile?--electron rich lone pair, it is going to be a very good nucleophile.3183

It is a carbanion; it is an example of one of the few carbanions we can make by deprotonation of a CH; that is how we are going to use it in our synthesis--is as a nucleophile.3192

This is described as an acetylide anion; because if this were acetylene just with the two hydrogens, this would be called acetylide.3206

These are acetylide-type anions; we call it that when we have a C- on a triple bond, an sp hybridized carbon.3213

Let's take a look at a possible synthesis then; how could we use an acetylide anion in synthesizing an alkyne of some kind?3221

The first thing we are going to do is we will start with an alkyne, a terminal alkyne; once again point that out; NaNH2,NH3.3230

Where did the NH3 come from?--again just to get used to seeing that; that is the typical solvent we are going to use when NH2- is our reagent.3243

NH3 is a reasonable solvent; just like if we were using methoxide as our base, we usually use methanol as the solvent; we very often use the conjugate acid as the solvent.3252

We should get used to seeing these conditions; again just a reminder here, this is not the same thing as Na,NH3;.3265

These are so similar; you really want to make sure that you are not confusing those and you make some flashcards, separating them out and delineating them.3275

Na,NH3, this is something that reduces the triple bond to an alkene; NaNH2 is a strong base that will deprotonate an alkyne.3283

I'm sorry... it would reduce the alkyne to an alkene; and this will deprotonate the alkyne; what is this going to do in this first step?3293

We are going to have our strong base; it is going grab that proton and it is going to convert this into the acetylide anion; the acetylide anion is a nucleophile.3301

If we treat it in a second step here with an electrophile like ethyl bromide or bromoethane, where is this electrophilic?--how would I recognize an alkyl halide as an electrophile?3316

Remember the bromine acts as a leaving group, pulls electron density away from the carbon; so this is partially positive; that is where we see that it is electrophilic.3331

What is going to happen?--what do you think?--with this nucleophile and an alkyl halide, what mechanism can happen?--how about the lone pair attacks the carbon and kicks out the leaving group.3341

What do we call that mechanism?--it is the Sn2; it is just backside attack; it is exactly what can happen and what will happen; what we do here is we form a new carbon-carbon bond.3350

This is something that organic chemists get very excited about when you form a new carbon-carbon bond because this is how we can build up new carbon chains and new carbon molecules.3366

It is happening because we have a carbon nucleophile reacting with a carbon electrophile; so we form a new carbon-carbon bond; we just synthesized a new alkene from an original alkene.3375

We started out with a new alkyne from an original alkyne; we started out with a terminal alkyne after this two-step synthesis--deprotonation followed by alkylation.3387

We could describe this as deprotonation followed by alkylation to describe each of the two steps that we did.3401

We now have an internal alkyne; so this is a way that we can add carbon groups to one or both sides of an alkyne starting material.3411

Let's look at a few examples of this; here is one example; we are starting with this alkyne; we are making this new alkyne.3427

We can pretty readily identify the three carbons in our starting material are still these three carbons in our product.3438

Which means this is a new carbon-carbon bond that needs to be formed in the reaction; what we do is we make a disconnection here as part of our planning, as part of our retrosynthesis.3446

We know that is the bond that we are going to cleave; then we need to think about the two carbons involved in that reaction.3463

If we want to form a carbon-carbon bond between these two carbons, that means one of those carbons must have started out as a nucleophile; one of them started out as an electrophile.3469

Which was which?--the carbon that is part of the triple bond, the sp hybridized carbon, what kind of behavior have we seen recently on that kind of carbon?3480

We have seen a lone pair and a negative charge; that means that would be a very good nucleophile; we can identify this one as--this was my nucleophile; which means this guy was my electrophile.3490

When I do my retrosynthesis--asking what starting materials do I need, I need to come up with a reasonable nucleophile.3502

My reasonable nucleophile would simply be a carbon with a negative charge at that position; we have seen that anion; that is stable anion; that is a good nucleophile.3512

How about this carbon though?--that is my electrophile; how do I make this carbon electrophilic?3521

It would be great to just put a positive charge here and say, if I had that carbocation, if I had this benzylic carbocation, and I hit it with this alkyne anion, I would definitely make my target molecule.3528

The problem is that this is not... you can't go to the stockroom and ask for a benzylic carbocation; it is a fleeting intermediate; it is not a stable reagent or starting material that we can use.3540

What we have to think of is what is an actual reagent that is stable that reacts as if it had a positive charge here that will still be electrophilic?3551

The strategy that we do is we simply add a leaving group; if we attach a leaving group here; your choice--bromine, chlorine, iodine.3563

Then we no longer have a carbocation; but we do have a partial positive; that is what we typically see for electrophiles; this would be a great electrophile.3572

What the beauty of doing a retrosynthesis like this is you can test yourself and ask if I had this nucleophile and this electrophile and brought them together, would it make this product?3581

Absolutely, because we know we would do an Sn2--attacks the carbon, kicks off the leaving group; that would be successful.3591

Our planning tells us what we need; now we come back to where we are; we are at propyne; we need to have the anion of propyne; we need the anion of propyne; where does that anion come from?3598

How do we go from a CH to a C-?--we removed an H+; we need to deprotonate; what we need is a very very strong base.3612

NaOH is not going to cut it; that is going to give just a small equilibrium; it is going to form a little bit of this; but it is still mostly going to stay as the undeprotonated species.3621

The strong base that we are going to use instead most often is NaNH2; there are other options as well; but NaNH2.3632

We should get used to seeing NH3 thrown in there as the solvent; that would be effective at doing a deprotonation.3640

Now that I have this, all I need to add is benzyl bromide, phenyl CH2Br, or benzyl chloride or benzyl iodide; your choice, anything like that.3647

Then we have an Sn2; and we have synthesized our target molecule; two-steps again--deprotonation, alkylation.3657

How about the next one?--this is a little more complicated because we no longer have a triple bond in our molecule.3670

Again a good first step is to identify the carbons in your starting material and find those carbons in the product.3677

Here they are; we started with three carbons; now we have four carbons; that means this methyl group is new.3686

That is going to be a disconnection we need to make because at some point in this synthesis I have to bring that methyl group in and form a bond between that and carbon number 3.3692

The other change that has taken place is I went from an alkyne to a trans alkene; both of these transformations we have seen in this unit; so we are capable of both of those.3702

The question we need to ask is: which one should we do first?--let's imagine doing our alkylation first; let's say we wanted to add the methyl group first; then convert the alkyne to the alkene.3716

Let's see if we can fill in those reagents; how do we go from a CH to a CCH3?--how do we replace this proton on the terminal alkene with a methyl group?3739

That is going to be an alkylation of the alkyne; that is our two-step procedure; step one is NaNH2,NH3, a strong base to deprotonate.3753

Step two, after we do that... in a multistep synthesis, you can either draw an arrow and then your product and then an arrow and your next product.3763

Or if it is really long, you can save some time and condense them over a single arrow; but you want to be very clear that the first step is separate from the second step.3771

The second from the third step; you are assuming, after each step, you do a reaction work up; you isolate your product; then you carry it on to the next step.3780

That is clear to do; but make sure you include these numbers here because that is critical to make your synthesis work.3788

After we do that deprotonation, then we are going to add in the methyl group; how do we make methyl an electrophile?--we need an alkyl halide; we will use methyl iodide.3795

When it is methyl, usually the bromine, iodine, and chloride are not a good choice because methyl iodide is a liquid; the other ones are gases; usually for methyl, methyl iodide is a better choice.3805

On paper, it is not as critical because it doesn't float away from paper; but in the laboratory, you would pretty much be using methyl iodide as your best choice.3816

I know how to do this transformation to go from the terminal alkyne to the internal alkyne; how do we go from an alkyne to a trans alkene?3826

This is one of the reduction reactions we saw; which one is it?--we want to do partial reduction; so is it the Lindlar's catalyst with hydrogen gas or is it dissolving metal reduction?3835

Lindlar's adds the syn hydrogens; we get the cis alkene; the dissolving metal, which is sodium and ammonia or lithium metal and ammonia, would do a partial reduction and give the trans alkene.3847

This looks like a reasonable synthesis; I think this will work pretty well; but let's consider what would happen if we tried the other way.3864

What if we started here and we said I want to first reduce the π bond and then I want to add on the methyl group; we know how to do this reduction.3871

We could do dissolving metal reduction here first to get to the alkene; but here is the question now: how do we go from an alkene with a hydrogen here and replace that with a methyl group?3885

If we try to add in a strong base here, can we deprotonate an alkene hydrogen?--no way; no reaction; this transformation can't happen.3905

Remember alkynes are very special that way; only alkyne CHs can be deprotonated; it is alkyne nucleophiles, acetylide type nucleophiles, that we are going to be using in our synthesis, not alkenes.3920

Another problem, even if we could have this happen somehow, how would you control the stereochemistry?3934

How would you be able to deprotonate just this trans one, and not the other one, so that you get the trans alkene?3939

Because there is stereochemistry in this product, we need to think to ourselves when we are doing our retrosynthesis and say: how do I get a trans alkene?3945

What reaction have I seen that gives specifically a trans alkene product?--I know that if I had this alkyne, if I had this alkyne, I could stereospecifically get the trans alkene.3955

That is part of the problem too--is this is a stereochemistry issue; but we also can't invoke reactions.3969

We don't want to mix our functional groups and just start deprotonating any carbon we want now; this is a reaction that is specific for terminal alkynes.3974

One last example, let's imagine going from this alkene to this alkyne; we have one, two, three, four carbons here; and one, two, three, four carbons here.3985

It looks like this is a new carbon-carbon bond; this ethyl group, this CH3CH2 is still a CH3CH2 so I know I should number it that way.4003

But my π bond is gone; that is interesting; I need to form this bond; let's think about how to form that bond; let's do our retrosynthesis asking what starting materials I could have.4014

What I need to consider is if I want these two carbons to come together and form a bond, that means one of them started out as a nucleophile, one of them started out as an electrophile.4028

Who is who?--which is which?--who would be the good nucleophile in this case?--it has to be the carbon that is part of the triple bond; this guy was my nucleophile.4038

Which means this guy must have been my electrophile; it must have been an electrophile for it to be attracted to the nucleophile.4049

What does this two carbon nucleophile look like?--it is a C- with a CH; it is the acetylide anion; that is a good nucleophile.4057

Who is my electrophile?--we have four carbons with a leaving group attached; remember we still have one, two, three, four; be careful with your line drawings.4069

It is easy to lose the carbon at this point; so don't hesitate to number your carbons; number them throughout so that you don't miss any carbons.4079

If I had this alkyl halide--bromide, chloride, iodide, and I reacted it with this nucleophile, would I get this product?--sure, I would expect an Sn2; that looks great.4085

The question is then how do I go from my alkene to this bromide?--I need this bromide in order to do my synthesis; but I am starting with an alkene.4100

It looks like the double bond is gone; I have added a bromine; what else?--there is also a hydrogen here that was new; how about if I just add HBr?4117

I can take an alkene and I can add HBr across the π bond--break the π bond, add the H and the Br; would that give this product?4126

What is the problem with just adding HBr?--what is the regiochemistry you would expect when you add an HBr?--hydrogen goes to the carbon with more hydrogens.4135

That is the end carbon in this case; that would give the wrong product; how do we get to anti-Markovnikov regiochemistry?--there is a few options we have had.4144

We have seen one case where we did hydroboration-oxidation; we could first make the alcohol and then convert it to the Br.4156

But we have actually seen a reaction with Br; it is a good thing we picked Br as our leaving group because we have seen a reaction with HBr that added anti-Markovnikov.4163

That was, instead of using a mechanism involving HBr as an acid, we threw in some peroxides; when we add in peroxides, we get a radical mechanism; and we get anti-Markovnikov regiochemistry.4171

That would be a way of adding the hydrogen to the middle carbon and the bromine to the end carbon; then once we have this, we can add in our sodium acetylide.4196

Which you can assume that you can just get commercially or you could show how you make that; it depends on the instructions for the particular assignment; you can do that as well.4208

One thing that I wanted to point out is, that I forgot to mention, is that this nucleophile is a very strong nucleophile; it is also a strong base.4221

FYI (for your information), if we tried to react this with a secondary leaving group or definitely something with a tertiary leaving group, then we are going to get E2 elimination instead.4235

For example, if I took cyclopentyl bromide and I tried to do a reaction with this to do an Sn2, remember Sn2 is very sensitive to sterics.4249

As soon as we have any kind of steric hindrance like this, rather than do the Sn2, it is going to give E2 as the major product.4267

For this alkylation process that we are talking about, we need to have an unhindered electrophile.4280

Something like a methyl halide, like methyl iodide we just saw, or a primary alkyl halide, primary RX, is a good Sn2.4286

If you don't want to use this peroxide, this radical mechanism, or you don't recall that, the other anti-Markovnikov mechanism that we should know is the hydroboration-oxidation.4299

In other words, we can add water across the π bond in anti-Markovnikov regiochemistry; that was BH3-THF, hydroboration-oxidation, H2O2 and base.4312

A few more reagents to remember if you choose to go this route; but that will work just as well.4329

We also have an extra step because we can't just add in the acetylide; we don't have a leaving group; what we would need to do is we need to convert this to a leaving group.4335

How do we make an OH a good leaving group?--several options; we can make the halide by using something like PBr3; or we could make it the tosylate by using tosyl chloride.4346

Either of those would be good; then we could react that with the sodium acetylide; we can get a Sn2 with our nice primary leaving group; that would be another route to it.4365

This step is a little longer because it requires conversion of the OH into something bearing a good leaving group.4380

This first method would be a little better because it is more succinct and a shorter synthesis.4386

That finishes it up for alkynes; I hope to see you again soon at Educator.com; thank you.4393