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Dr. Laurie Starkey

Dr. Laurie Starkey

Conjugated Dienes

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 (25)

2 answers

Last reply by: Jinhai Zhang
Tue Sep 29, 2015 11:11 AM

Post by Jinhai Zhang on September 27, 2015

Dear Prof. Starkey:
the the diene you mentioned, the addition of X2, halogenation of alkene has disparate mechanism of HX, since there no carbocation formed in the reaction halogenation of alkene, how does the 1,4 addition happen for diene?
Thank you for answering.
Sincerely

4 answers

Last reply by: Professor Starkey
Wed Jul 19, 2017 10:32 AM

Post by Dalina dom on May 19, 2014

Hi Professor Starkey
I really love your lectures and your explanations.I am really enjoying your lectures. I am wondering if you are planning or will plan to add more lectures such as advanced topics: more in depth details of diels alder including stereo-specificity (in the diene the out and in substituents) which you have mentioned that you will not discuss it at this level. Also if whether or not you will add more lectures to this lecture such as other the pericyclic reactions: other examples of cycloaddition, sigmatropic rearrangement(cope, claisen etc. etc.) and electrocyclic reactions.  Also do you have lectures on carbenes (or in the future).  

2 answers

Last reply by: Brijae Chavarria
Sat Feb 21, 2015 7:55 PM

Post by Gear McMillan on April 30, 2014

Kinetic VS. Thermodynamic control shows the product on the right as having two chlorine halogens attached to it but then in the explanation of the more stable product is has a H where the Cl was in the 1,4 product. Now I believe I have figured it out but that is still an error that cost me ten minutes to fifteen minutes. Let's fix it for the next person

2 answers

Last reply by: Stephanie Bule
Wed Jul 3, 2013 8:15 AM

Post by Stephanie Bule on July 2, 2013

Also, for the enantiomer of the bicylic compound on the Diels-Alder rxn with cycle Dienes, it looks like you put the EWG (CHO) on carbon 5 which is a structural isomer instead of being a stereoisomer. In order for it to be a stereoisomer wouldn't you just switch the CHO from being endo to exo? - You did mention that if you rotated it you would be able to see it, so maybe I'm not looking or thinking of the structure right.

1 answer

Last reply by: Professor Starkey
Wed Jul 3, 2013 12:33 AM

Post by Stephanie Bule on July 2, 2013

professor Starkey, at around minute 25, on the reaction is reversible slide, after you formed the resonance structures, the final (lower in energy - more stable product) has only one chlorine atom to it, and a Hydrogen in place of the first chlorine atom. this isn't correct, right? The Hydrogen should still be a chlorine.

2 answers

Last reply by: Yun Seon Heo
Mon Sep 24, 2012 9:47 AM

Post by Yun Seon Heo on September 23, 2012

Professor Starkey, I have a question about "retro DA Reaction". You have mentioned during lecture that cyclopentadiene is really good for DA reaction since it's locked in cis. However, you've also said it reacts with itself sometimes so it is needed to reverse DA reaction by heating. (I believe "reverse DA reaction" is "Retro DA reaction") How much heat does it need to reserve it back to cyclopentadiene?

From my understanding, some heat is still needed to do DA reaction but I guess for retro DA reaction, "more" heat is required? Can you please tell me how the processes of DA and retro DA reactions are?

2 answers

Last reply by: Professor Starkey
Wed Jul 19, 2017 10:27 AM

Post by Michael Grier on April 17, 2012

Help.... I am in Organic 2 and we are discussing carbohydrates and I need help. Major help. Is there a lecture that can help me?

1 answer

Last reply by: Ramez Younis
Sun May 15, 2011 11:44 PM

Post by alexandra ortega on March 6, 2011

we need more teachers like you who make organic interesting!

Conjugated Dienes

Which diene has the larger heat of hydrogenation and which is more stable?
  • The more stable diene has a smaller heat of hydrogenation.
  • Conjugated diene = double bond separated by one σ bond.
  • Isolated diene = double bond separated two σ bond.
  • Compound B is an isolated diene. It has a higher heat of hydrogenation and is less stable than Compound A.
  • Compound A is a conjugated diene. It has a smaller heat of hydrogenation and is more stable than Compound B.
Compound B has the larger heat of hydrogenation. Compound A is more stable.
Draw the 1,2 and 1,4-product for the following reaction. Then label each one as kinetic or thermodynamic and predict the more stable product.
  • The 1,2-product is formed faster at a lower temperature and is also known as the kinetic product.
  • The more stable 1,4-product is formed predominately at equilibrium and is also known as the thermodynamic product.
Draw the product for this Diels-Alder reaction:
Classify each diene as reactive or unreactive in a Diels-Alder reaction:
  • Diene must have ß-cis" conformration to react in a Diels-Alder reaction.
  • Diene Ä" has an s-cis conformation therefore it is reactive.
  • Diene "B" has an s-trans conformation and cannot rotate to form s-cis so it is unreactive.
  • Diene "C" can rotate to form s-cis conformation therefore it is reactive.
Draw the product for this Diels-Alder reaction:
  • The endo product is preferred in a Diels-Alder reaction.
Draw the product for this Diels-Alder reaction:

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

Answer

Conjugated Dienes

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

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

    Transcription: Conjugated Dienes

    Welcome back to Educator.com.0000

    Today, we are going to be talking about conjugated dienes--what they look like and how they behave and what sort of reactions they undergo.0002

    A diene has two π bonds; a conjugated system has those π bonds in an alternating fashion--so we have a double bond, and then a single bond, and then a double bond.0009

    OK, so what we have is a p orbital on each carbon for the first π bond, and then a p orbital on each carbon for the second π bond; so what we end up with is aligned sets of p orbitals, where those π electrons can delocalize over multiple aligned p orbitals.0022

    What we get is resonance, and that makes these systems very special and allows them to undergo some unique reactions.0042

    Now, there are two orientations--two conformations that a diene can have.0050

    This one is described as an s-trans conformation; so you can see that these groups are trans to each other (on opposite sides), but we call it s-trans because it is trans about a single bond, or a σ bond.0057

    In other words, you can rotate around this; there is nothing stopping this from rotating.0073

    And if it did so, it would have this conformation: we call this conformation the s-cis conformation, because it's cis about a single bond.0078

    And, although these two conformations exist, the equilibrium is favored in the reverse here; the trans is more stable, because the s-cis has hydrogens that are on these end carbons, and they are forced to be in a coplanar arrangement here.0090

    And so, we have some steric interactions with those two hydrogens.0109

    So, s-cis is less stable; we are going to see that this conformation is going to be necessary for certain reactions to take place.0112

    Now, let's talk about this nature of being conjugated, and what kind of stabilization this resonance imparts, and how we can get some evidence for that.0122

    Let's take a look at three different types of dienes: each of these has five carbons, so these are all pentadiene examples.0134

    Here, the two double bonds are right on top of each other--we call this a cumulated diene, where the p orbitals are perpendicular--the ones on this π bond are perpendicular to the ones for the second π bond.0143

    Here, we have π bonds that are unrelated--they are isolated; we have...the p orbitals on these two carbons have no relationship at all to the p orbitals on the other two carbons.0157

    And then, finally, we have the conjugated system, where we are saying we can have some interaction here, and some delocalization, because of resonance.0171

    We can take a look at the heats of hydrogenation for each of these dienes to see if we can observe some differences in their energies.0181

    When you catalytic-hydrogenate each of these, they give the same product (they give pentane)--all of those have the same energy, so when we measure the ΔH, that gives us a relationship that tells us something about the initial energy of our starting materials.0190

    Let's take a look at the isolated π bonds, initially: the energy released there is -60.7 kilocalories per mole--that is essentially the heat of hydrogenation for an alkene, times 2.0204

    So, because these double bonds are separate from each other and have no interaction, you simply get twice as much energy out as if you had just one π bond.0216

    However, when you force those two π bonds to be cumulated to one another, we actually get out more energy from the reduction of this diene, meaning it started out higher energy.0227

    This is an unstable arrangement of double bonds, and when you allow them to be conjugated with one another, you have less energy being released, which means your diene must have started at a lower energy.0237

    So again, if we do a quick little energy diagram comparing these three, they are all going to the same product--the pentane product--but A must be starting at a higher energy than B, and C must be starting at a lower energy than B.0251

    C is the most stable diene, because it has the smallest amount of energy to release upon hydrogenation.0268

    OK, and it because of this resonance energy, the energy that we get from that stabilization.0277

    And one thing I forgot to point out on the past slides--some physical evidence for this resonance interaction--is that this σ bond is shorter than a normal single bond.0283

    OK, because you have these p orbitals on each carbon that are drawing them closer together because of that overlap, it gives us some hint that those electrons are being delocalized over all 4 carbon atoms.0302

    OK, related to these conjugated systems are allylic systems, like an allylic carbocation and allylic radicals; let's take a look at how those look.0316

    Allylic means that you are next to a π bond; so this is an allylic carbocation; an allylic carbocation is uniquely stable, because it has resonance; you can delocalize that positive charge to another carbon.0327

    One way that you can look at an allylic carbocation is to say, "Well, we have a π bond here, which means a p orbital on each of these carbons sharing two electrons, and a carbocation is also sp2 hybridized, so it has an empty p orbital."0340

    And so, when you look at this orbital picture, you can see how very easily those two electrons can be shared among these aligned p orbitals, and it would be very easy to delocalize the charge and delocalize those two electrons over the p orbitals.0359

    That is an allylic carbocation, allylic radicals, the nearly identical picture...we have two electrons in a π bond, and then we have a radical in a third p orbital.0378

    And each of these discrete Lewis structures has a localized π bond and then a radical on the third p orbital.0391

    But again, of course, because this resonance exists, what does the true structure look like?--it is some kind of blend of both of these resonance forms--something in between, where we have partial π bond character, and those three electrons are being distributed among all three carbons.0399

    Now, let's take a look at some reactions we have seen in the past for alkenes, and see how that is going to apply or how they differ when it comes to dienes.0422

    For an alkene, we saw some addition reactions--electrophilic additions; for example, if we react an alkene with HX (HBr, HCl, something like that), we could break the π bond, add a hydrogen and a halogen, and we do so with a regiochemistry called Markovnikov addition, where the hydrogen with more hydrogens is the one that gets the hydrogen.0432

    OK, we could also do electrophilic additions with halogens like chlorine and bromine, and we could form the bromonium ion, and the second bromine can come in and open it up, and so we can add two chlorines or two bromines across a π bond, as well.0454

    We have also seen some reactions of conjugated systems; if you recall, an alpha, beta unsaturated ketone (or aldehyde, in this case)--an alpha, beta unsaturated ketone is electrophilic in two positions because of resonance delocalization.0469

    And, when a nucleophile adds, it can either add to this end carbon (we call that 1,4 addition), or it can add to the carbonyl carbon (we call that 1,2 addition).0487

    We have seen some evidence in the past where, when we have a conjugated π system, those are going to interact, and we can get a mixture of products based on that interaction.0498

    When we take a look at a conjugated diene, and we add an electrophile to it (like HX or X2), we are going to get two possible products out.0510

    In one product, we are going to break just the first π bond here and add H and X; we are going to do it with Markovnikov regiochemistry, just like we have seen before.0523

    So, we'll add the hydrogen to the end carbon and the halogen to the middle carbon.0534

    And that same reaction can happen with chlorine or bromine, where we add a halogen to each of the first two carbons.0537

    OK, so we'll get that product: in other words, the diene can act just like an ordinary alkene; but there is a second product that can be formed, in which case, the hydrogen adds to the first carbon and the halogen adds to the last carbon, and the double bond has moved to be between the middle two carbons.0545

    This can happen with the addition of HX; it can also happen with the addition of X2 (chlorine or bromine), and we describe these products--we call these products 1,2 addition, because they have added 1,2; we call these 1,4 addition because they have added 1,4.0564

    We will take a look at the mechanism; we will see in which cases one product is favored over the other and so on.0580

    OK, now, before we get into the mechanism of the diene, let's make sure we review the mechanism of the alkene, and we understand what was going on there.0587

    If you had propene and reacted with HCl, the very first step--it's a two-step mechanism; the first step is going to be to protonate the alkene with the strong acid.0595

    And this is the step where you decide the regiochemistry--is the proton going to go to the first carbon or the second carbon?0606

    Now, one carbon is going to get the proton; the other carbon just lost this π bond, so it is going to have a positive charge; we are going to form a carbocation intermediate.0615

    And so, the way we decide which is the major product: we compare these two intermediates; we see that one is a secondary carbocation, and the other is a primary carbocation.0625

    What do we know about carbocation stability--which is the more stable one?--the more carbon groups, the more stable, because remember: carbon groups are electron-donating, so that is going to be a good thing for the positive charge.0641

    The secondary carbocation is more stable, so the primary carbocation is less stable, and it is not formed.0653

    This was the rationale behind what we described as Markovnikov's rule.0663

    The hydrogen goes to the carbon with more hydrogens so that the carbocation ends up on the carbon with more carbons; that is going to be a more stable carbocation.0668

    What is our second step?--we form the carbocation; now, the Cl- we formed in the first step is going to attack; so we protonate, and then we attack, and we are done.0679

    We have our addition reaction.0690

    OK, so reviewing that for an alkene--let's see how that is going to vary when we start with a diene instead of an alkene starting material.0693

    Well, it is going to begin the same way: if you take a diene and react it with HCl, you are going to protonate the π bond, and we are always going to do it in a Markovnikov fashion so that we always get the more stable carbocation.0702

    We are always going to form the most stable intermediate possible, which means we are going to add the proton to one of these end carbons to give a carbocation (and this second double bond is still here).0714

    And when we look at the carbocation we just formed, we see that it is a special kind of carbocation, because it is next to a π bond: what do we call that?--it is an allylic carbocation.0733

    What is special about it?--well, it has resonance: I can move this π bond over, and that will locate the positive charge at two possible positions.0746

    Hopefully, now you can see how it is that we can get to a 1,2 product or a 1,4 product; that comes from having the chloride attack at the first carbon or having the chloride attack at the last carbon.0763

    Because both of those carbons have partial positive character, the chloride could attack either way; and we get these two different products out.0781

    Now, let's talk about these two products a little bit more: this first one, the 1,2 product, is described as the kinetic product; this is the product that can be favored if we have cold reaction conditions.0789

    OK, it is called the kinetic product because this has the lower transition state energy; we will look at that transition state in just a moment to see why that is.0799

    It has the lower transition state energy, and therefore it is formed the fastest.0810

    And remember, kinetics has to do with the rate of the reaction, so the kinetic product is going to be the one that is formed the fastest.0818

    OK, a little note here: it is not about having the more stable carbocation intermediate; this is a common misconception, or a common misstatement, when trying to explain this reactivity.0825

    It is not acceptable to say that this came from the better carbocation--why not?--I mean, it looks good: this is secondary; this is primary; but why can't you say that this kinetic product came from a better carbocation?0845

    Are these two different carbocations that were competing, like in Markovnikov's rule--if we protonate here, or protonate there, we get two different carbocations?0858

    No, there is one carbocation: there are just two ways to draw it.0868

    Remember, the actual structure is a blend of these two; so they both--both of these products--come from the same carbocation; we will just see that the one leading to the 1,2 product goes through a lower-energy transition state; that is what makes it faster.0872

    OK, the 1,4 product is described as the thermodynamic product, because this is what is favored when we have hot reaction conditions, and it is called the thermodynamic product because this is the more stable product.0887

    Now, if you compare these two products (the 1,2 and the 1,4), what do you see about the structures that would help you explain why this is more stable?0902

    Is it about where the chlorine wants to be?--we have never heard anything about chlorine's preferences.0914

    But how about the double bond--how would you describe these double bonds?0920

    This one is terminal; it is monosubstituted; this one is internal--it's disubstituted, right?0924

    The more substituted a double bond, the more stable it is; so it's because we have an internal π bond that it is the more stable product.0933

    OK, so kinetics has to do with the rate of a reaction; thermodynamics has to do with the product stability.0943

    If we take a look at an energy versus progress of reaction diagram, we will be able to see both of these things competing.0951

    We are starting at some preliminary energy for our butadiene (in this case, 1,3 butadiene and HCl).0959

    OK, the first step of the reaction, remember, is protonation to give a carbocation; so our carbocation is going to be some high-energy intermediate.0966

    We could draw both resonance forms here; but remember, that is the same carbocation, and so, to go here and protonate, we have to overcome some barrier, some transition state, to get here.0980

    OK, but what is key is: whether you are trying to make the 1,2 product or the 1,4 product, they both start the same way: they always both start by protonating the diene in Markovnikov regiochemistry to give an allylic carbocation--a resonance-stabilized carbocation.0993

    OK, and when we are done, we expect our products to be lower in energy than our starting material, because we are doing an addition reaction: we are breaking a weak π bond and forming a stronger σ bond.1011

    OK, and what we said was that, of our two products, we said that the 1,4 product is the more stable product; so that is where the double bond was in between.1023

    The 1,2 product was not as stable, because our double bond was terminal (or actually...the wrong way...double bond over here, and chlorine over here).1036

    OK, so we know where we are going; and what we just pointed out in the last slide (and will talk about next) is that the 1,2 transition state is lower energy than the 1,4 transition state.1048

    The path to go to the 1,2 product goes through a lower-energy transition state and ends up at this higher-energy product.1066

    To do the 1,4 product, we go to a higher-energy transition state, but then we end up at a lower-energy product for the 1,4.1077

    OK, now let's see if we can explain why we have this energy difference between the transition states.1088

    What is happening in our transition state (the 1,4 transition state) is: this is our second step--what we are doing is: our chloride (we have a chloride here--sorry--as our other intermediate in this step)...now, that chloride is attacking the carbocation.1095

    It is attacking either at this position or this position; so in the transition state, the nucleophile and electrophile are coming together; you are starting to form a bond.1112

    So, we have a partial bond between the carbon and the chlorine; we have partial charges: as the charge on chlorine starts to dissipate, the charge on the carbocation starts to dissipate; so this is what our transition state looks like.1120

    We use a double dagger to indicate a transition state.1131

    That is the 1,4 transition state; and here is the 1,2 transition state, with the chlorine attacking the second carbon instead.1135

    Now, when you compare these two structures of the transition states, what do you see about them that might be different in their stabilities?1143

    Now, the double bond is in different places; we saw that was an issue to determine the product stability; but for the intermediate, it is going to be the charges that you have that are the biggest source of instability.1153

    So, how would you describe the two charges that you have?1166

    In the 1,4 transition state, I have a primary partial positive; and in the 1,2 transition state, I have a secondary partial positive.1169

    And, just like a secondary carbocation would be more stable than a primary, a secondary partial positive will be more stable, as well.1182

    OK, so what we could say is that for the 1,2 transition state, we have a better partial positive; it is secondary; it is also allylic (they are both allylic--we could say this is primary allyic versus secondary allylic).1190

    OK, that means that the 1,2 transition state is lower in energy (which we have shown here--we have drawn it at a lower-energy spot), and if the transition state is lower in energy, that means the 1,2 energy of activation is lower.1210

    If the transition state is lower, that means the energy of activation (the energy of activation is right here)--the energy required to get to that transition state--is lower; we are comparing that, of course, to the energy of activation for the 1,4.1232

    So, if the energy of activation is lower, that means it is a faster reaction.1249

    That is why we describe it as being the kinetic product.1257

    The faster reaction is the one that goes through the lower-energy transition state: so the 1,2 is called the kinetic product because it is formed faster; the 1,4 is called the thermodynamic product because it is a more stable product.1263

    So, even though it took more energy to get there (it is a slower reaction--it is more difficult to do this reaction), it goes to a better place; so we will see different reaction conditions favor each one.1276

    If you have cold reaction conditions, then you are limited in the amount of energy that you have; so therefore, whatever products form fastest (the 1,2 in this case)--that is formed immediately, and that is going to be your major product.1292

    OK, but how is it that adding heat to a reaction is going to somehow cause this 1,4 product to be the major product?--that is what we want to talk about next.1307

    OK, we will call that kinetic versus thermodynamic control; and so, here are two examples.1318

    If we take butadiene and we react it with chlorine (just one equivalent of chlorine in each case), and we do one at -15 degrees (that looks like cold reaction conditions), and then we have a little Δ here to symbolize heat--this looks like hot reaction conditions.1322

    OK, what do we expect to have as our major product?--well, we can form both the 1,2 and the 1,4; this is not an all-or-nothing.1340

    You will usually get a mixture out; OK, but in cold reaction conditions, the major product is going to be the 1,2; so we get something like 60% and 40%; so the 1,2 is major and the 1,4 is minor.1351

    OK, but if we do this under hot reaction conditions, we still get a mixture of 1,2 and 1,4, but it moves: we get about 30-70, where now the 1,4 is the major product.1373

    Kinetic control will favor the cold conditions, while hot conditions will have thermodynamic control.1387

    But what is very interesting is: if you take this product mixture that you got initially, and you heated it, it will redistribute to not have the 1,2 as a major product anymore, but have the 1,4 as the major product.1395

    So, in other words, there is no longer any butadiene or chlorine left; but just these products can reorganize themselves to be different products--meaning somehow, this 1,2 product is disappearing, and more 1,4 product is reappearing.1414

    How is that happening--what is going on here?1430

    Well, the key is that the reaction that we are looking at is reversible.1432

    Even though you can form 1,2 product quickly initially, it is possible for that reaction to reverse and go to 1,4 product.1437

    Take a look at our 1,2 product; remember, our 1,2 product is less stable.1446

    Even though it is formed the fastest (because it had that secondary partial positive), because it is less stable and higher-energy as a product, it is more likely to do the reverse reaction.1453

    So, if it was fast to form the product, that means it also is fast (or a little faster, compared to the other) to do the reverse reaction.1473

    That reverse reaction is our leaving group leaving to give back the carbocation; and once you are at that allylic carbocation--once you are here--now when the Cl- adds back in, it can add to either position again.1481

    It is going to preferentially want to do that to get to this more stable product.1502

    OK, so this is how when you add heat--when you give it enough energy--you give an opportunity for things to equilibrate.1507

    OK, so let's say some things about this 1,4 product: remember, this is the more stable product, because it has the internal π bond; and because it is more stable, it is less likely to do the reverse reaction.1516

    So, once you make the 1,4 product, you are more likely to stay as the 1,4 product.1531

    A reversible reaction--the key is having a reversible reaction, and with the addition of heat (so if you have a reversible reaction and you provide it with enough energy to do that reversible reaction), it allows products to equilibrate.1537

    That is the key here: thermodynamic control assumes that you have equilibration; and when you allow a reaction to go forward and back and forward and back and forward and back, it eventually is going to build up in concentration of whatever is the most stable product.1564

    OK, we call that the thermodynamic sink--the notion that our product mixture is going to continue until you get to the most stable place that you can be.1580

    OK, now let's shift gears and take a look at a different reaction that dienes can undergo.1595

    What we just looked at were electrophilic addition reactions and the idea that an electrophile can either add 1,2 or 1,4; another reaction that is unique to dienes is a reaction called the Diels Alder reaction.1600

    Now, what happens in this is: we need a diene, as shown here; it needs to be a conjugated diene (something like 1,3 butadiene), and the thing we are going to react it with is something that loves to react with diene, so we call it a dienophile.1613

    We are going to react a diene and a dienophile; we are going to have, as our only reaction conditions, heat (and sometimes pressure--you could do that too).1630

    But all we need to do is heat this up; and the reaction that occurs is as follows.1637

    One end of the diene reacts with one end of the dienophile, and we form a bond; and the other end of the diene reacts with the other end of the dienophile, and we form a bond.1642

    The mechanism is actually just a single-step mechanism--one step, all occurring at once: the diene attacks the dienophile, the dienophile kicks its π bonds up and attacks the diene again, and the double bond moves over here.1653

    6 electrons moving in a ring--we describe this as a paracyclic reaction, where all of our cyclic transition states and all of our electrons move in a concerted fashion--and what happens is: we have 1, 2, 3, 4 carbons in the diene and 5, 6--two more carbons in the dienophile.1670

    We end up forming a 6-membered ring: 1, 2, 3, 4, 5, 6.1689

    We get a 6-membered ring...and something else is missing here: notice that these double bonds are gone, but we just moved a double bond here to be between carbons 2 and 3.1696

    So, when we track all of those 6 electrons and where they go, we are going to get a cyclohexene product.1705

    As a Diels Alder reaction, it always gives a 6-membered ring, and it always has a double bond here.1714

    It also forms two new carbon-carbon bonds; so this is a really cool technique for organic synthesis, because it is a way of building new carbon structures and building 6-membered rings.1721

    This is described as a cyclo addition, because we have an addition product and we form a ring; it is called a 4+2, because one component has 4 π electrons, and the other component has 2 π electrons; so it is described as a 4+2 cyclo addition.1735

    It is one subset of a larger class of reactions, called pericyclic reactions; the Diels Alder is just kind of the most famous one of those, so that is the one we will study as an introduction to this class of reactions.1751

    OK, so let's study, one by one, the different components: let's look at a dienophile in the Diels Alder reaction.1764

    In most cases, the dienophile acts as an electrophile; it can be either an alkene or an alkyne, and it is usually best--it is going to be a good Diels Alder reaction if it's electron poor.1770

    A lot of times, what is done is: an electron withdrawing group is added; so we have a double bond, and we add one or two or three or even four electron withdrawing groups to that to make it readily undergo Diels Alders.1782

    Our EWGs (our electron withdrawing groups) are the same groups you have seen before: carbonyls, like an ester or a ketone or an aldehyde; cyano...right?--those are the groups that we have seen as electron withdrawing groups.1796

    OK, and why do they make them good electrophiles?--well, what all electron withdrawing groups do is: they withdraw electron density out of the π bond.1810

    So, if we look at the resonance form for this ester, we know that this resonance form exists: and what does it do here?1820

    It makes that electron poor.1831

    That makes it a good electrophile: it puts some partial positive character here and pulls electron density out of the double bond, and that makes it behave as a good dienophile.1835

    Let's see an example where our dienophile is an alkyne--does this look like it would be a good dienophile?1850

    I have 2 ester groups, 2 electron withdrawing groups; so this would probably be a very good Diels Alder.1856

    We have our dienophile; we have our diene; and we are always going to line it up like this, so that the two double bonds in the diene are kind of pointing toward the dienophile.1862

    We are going to do that so we can very easily see the two bonds that are being made.1875

    And then, our mechanism, because it is just a one-step mechanism--it's a concerted reaction, one-step mechanism; it's so easy to draw; it's helpful to do that.1880

    It also doesn't hurt to number your carbons: we will always have four carbons in our diene--at least those four carbons, and then there will be two more (5, 6): 1, 2, 3, 4, 5, 6.1889

    And then, what is missing here?--we will always have this double bond between carbons 2 and 3; there is our cyclohexene; we have our ester groups on carbons 5 and 6 (ethyl ester, ethyl ester).1902

    And what else is missing?--between 5 and 6, we had two π bonds; only one of them was involved in the Diels Alder reaction, so the other one stays behind.1918

    If we were to use an alkyne as our starting material, we would get a cyclohexadiene product out.1926

    We would always have these two double bonds opposite each other after using an alkyne.1936

    OK, what does a diene look like?--now again, the diene, typically, in most Diels Alder reactions, acts as the nucleophilic component.1943

    OK, so it is best if it is electron rich; it often has electron donating groups, like an alkyl group or an ether group.1951

    OK, it is not possible to have an OH: an OH can also be an electron donating group, but we can't have that on the diene; and what is the problem there?1960

    Let's imagine trying that: what happens if we put an OH group on a diene--what functional group does that give us here?1968

    When you have an alkene and an alcohol on the same carbon, this is an enol; OK, and an enol is not a stable functional group.1976

    What does it do?--it tautomerizes to the ketone...in this case, the aldehyde.1984

    OK, so it would be impossible to make an OH on a diene, but you can have an O-R; you could have just an alkyl group; and so remember, alkyl groups donate electron density inductively, so that makes this more electron rich.1991

    Something like a methoxy group would donate electron density by resonance; this lone pair is allylic, so we can add it in.2005

    And when we take a look at that resonance form, what do we see?--this is now electron rich.2017

    That is what makes an electron donating group; it makes an electron rich diene, which makes it even hotter for doing a Diels Alder reaction.2023

    OK, now another thing that we have to have with the s-cis: I mentioned how that we will always want those two double bonds being pointed towards the dienophile--it turns out that that is a requirement for the Diels Alder.2033

    If it is going to be a concerted mechanism, and it happens all at once in the 6-membered transition state, those have to be able to line up with the dienophile so that we can form the 6-membered ring.2041

    OK, but now, sometimes we are going to see our diene presented in an s-trans configuration; that is OK, and that is usually the way we draw it, with a zigzag here, because it is the most stable.2051

    But what we have to recognize is: before we do the Diels Alder, we must rotate it into the required s-cis conformation; now, we can line it up and do the Diels Alder.2061

    That is part of what the heat is here for--that is part of the requirements of the Diels Alder: part of that energy that is going in is to rotate it to the less stable s-cis conformation.2074

    Now that it is here, now it is able to do the Diels Alder.2085

    2, 4, 6 electrons...and so what does our product look like?--we have a double bond up here, and our two methyl groups; and on this carbon...this carbon is right here; it has the two cyano groups.2089

    OK, so a lot of times, to do our Diels Alder, we have to flip this over; we are just taking that double bond and flipping it up--in this case, flipping it down.2107

    It is definitely worth redrawing it before you go to predict a product, because then you are less likely to make mistakes in drawing the product.2118

    OK, let's see another example--how about this dienophile reacting with this diene?2126

    Well, the problem here is...now again, this is s-trans (right?--we have one double bond going in this direction, and another going in this direction), but how about if we tried to rotate, to flip one over so that it would be s-cis--is that possible in this case?2132

    The presence of those rings locks them in this position; we could described this as being locked in the s-trans conformation; so no matter how much we heat this or how much we try, there is going to be no Diels Alder reaction.2147

    It must get into that s-cis conformation in order for the Diels Alder to occur.2161

    Now, a lot of times, the kind of diene we use is a cyclic diene, like this one: cyclopentadiene is very good at doing a Diels Alder.2169

    What is great about cyclopentadiene is: because it is in a ring, these double bonds are held in an s-cis conformation; they are locked in that conformation, which means they are just always ready to go (to do the Diels Alder) in an instant.2176

    In fact, cyclopentadiene is so good at doing the Diels Alder, it reacts with itself and does a self Diels Alder, where one equivalent acts as the diene; the other acts as the dienophile; and you get a dimer out.2190

    Any time you want to use cyclopentadiene, you have to distill it fresh, and you add heat to cause the reverse Diels Alder, so that it breaks up and gets back to the cyclopentadiene; and then you can distill that and use it fresh for your Diels Alder reaction.2206

    Now, the stereochemistry we are going to see gives something that we are going to describe as an endo product: and we will see what that looks like in just a moment.2224

    First, let's draw our Diels Alder product.2231

    Again, it is important to identify the terminal carbons of the diene, because those are the carbons that are going to react with the dienophile.2234

    OK, again, a good dienophile--it has some cyano groups on there, so that looks good.2246

    Let's number our carbons: 1, 2, 3, 4, 5, 6.2250

    OK, and we are going to be forming a 6-membered ring: 1, 2, 3, 4, 5, 6.2256

    Our double bond...I'm sorry, let's go ahead and do our mechanism.2265

    This π bond comes up; this π bond comes up; this π bond comes over; so there are our 2, 4, 6 electrons.2268

    We'll have a double bond here between 2 and 3, and we have our cyanos at 5 and 6; but notice that, right here, connecting carbons 1 and 4, we have this CH2 group.2275

    This is now going to act as a bridge over the cyclohexane ring that we just formed.2289

    We can draw it as a wedge coming up out of the page; we can draw our 1-carbon bridge, our methylene bridge.2296

    Now, if this bridge is drawn up, as shown, it turns out that these cyano groups end up pointing away from the bridge: that is what we call the endo stereochemistry.2306

    Now, it is possible to draw it like this; but usually, we draw it in a three-dimensional perspective that looks more like the actual structure, the actual shape of the molecule, where we kind of look at it from the side.2318

    So, kind of like we use the chair conformation (we draw the line drawings of that, where we are kind of looking at it from the side, and then we get rid of our dashes and wedges), we are doing the same thing here.2334

    OK, so usually we draw it like this; this is good to practice this; and what this is saying is that, when this carbon chain is up, then the cyano groups are going to be pointing down.2345

    We have a hydrogen here, and we have a hydrogen here; this is called the endo product.2359

    The endo product is preferred; this is going to be the major product.2367

    OK, just for comparison, what is not happening is: we don't get the bicyclic product where the cyano groups are pointing up in the same direction as the bridge.2373

    This product we call the exo product, and this is not formed.2388

    OK, so this is just a discussion of stereochemistry: we are asking about the groups that are on the dienophile: what is their relationship to the bridge that we have?2395

    Now, I am not going to get into why the endo is preferred; it has to do with when these cyano groups line up with the dienophile...with the diene...2406

    The electron withdrawing groups can either line up so that they go underneath the diene, or they can line up the other way, so that they point away from the diene.2418

    They prefer to line up underneath the diene, because then you have additional orbital overlap between the electron withdrawing groups and the diene p orbitals.2426

    OK, so because that orientation is preferred, we end up with the cyano groups, or whatever electron withdrawing groups we have, pointing in the down position.2436

    OK, let me just talk a little bit more about this endo versus exo, so we can get this terminology down--especially because this is the first time we have seen these kind of bicyclic systems.2445

    This is called norbornane as the common name, but the IUPAC name--how would you name a bicyclic compound?2456

    Well, it is called a bicyclic compound because you would have to cut two bonds in order to become an acyclic product; so you would have to cut one bond, and you would still have a ring; you would cut a second bond, and then you would have no more rings left.2464

    That is why it is described as a bicyclic compound.2478

    Now, overall, this is still a 7-atom ring, a 7-carbon molecule; so it's a heptane.2481

    If there were just one ring, we would call that cycloheptane; because there are two rings, we call that bicyloheptane.2490

    And then, what we do is: in these brackets, we list the bridge sizes in decreasing order.2497

    OK, so if you look at this norbornane, we describe these positions as the bridgehead carbons.2503

    Those are the carbons that are shared with both rings; and if you look at it a certain way, you can see that those two carbons are connected by three bridges: here is a 1-carbon bridge; here is a 2-carbon bridge; and here is a 2-carbon bridge.2517

    The way we would name this compound is: we would call this bicyclo[2.2.1]heptane.2534

    We list the sizes of the bridges in decreasing order, with periods in between: bicyclo[2.2.1]heptane.2541

    Really briefly, let's look at another bicyclic example, and see if we can do the name for that.2549

    This is another bicycloheptane: there are two rings, and there are 7 carbons total, so this is bicycloheptane.2554

    Find the bridgehead carbons (right here and right here), and then ask how many carbons are in all of the bridges connecting those two bridgehead carbons.2564

    Here, starting with our biggest one: our biggest carbon bridge is right here; it has 1, 2, 3, 4 carbons.2577

    The next biggest bridge is right here: it has 1 carbon; and the last bridge is right here--how many carbons are there in that bridge?--there are 0 carbons; the two bridgehead carbons are directly connected.2585

    So, we call that a bicyclo[4.1.0]heptane.2596

    OK, so just a little brief introduction to that IUPAC: so, when we look at norbornane, we have this as our smallest bridge; we look at the positions here.2601

    Knowing these are tetrahedral...we have 2 positions that are pointing down and 2 positions that are pointing up.2614

    And the ones that are pointing up in the same direction as that bridge, we describe as the exo position; and the ones that are pointing away from the bridge, and kind of in this cave on the inside of that cup shape, we call the endo.2621

    So, the exo and the endo...and so, what we find is: when we get a bicyclic product like this in a Diels Alder reaction, we choose to put the electron withdrawing groups in the endo position, away from this bridge.2639

    OK, let's see if we can do an example.2656

    Here is a cyclic diene: there are the two carbons of our diene that are going to react; here are the two carbons of our dienophile that are going to react.2660

    Those are the two new bonds that we are going to form; you can always find your 6 carbons that are involved: 1, 2, 3, 4, 5, 6.2671

    There will always be 6 carbons involved; so we are going to form a 6-membered ring, and now we are going to have a 2-carbon bridge connecting those bridgehead positions.2679

    The shape of the molecule is going to look like this: it's going to go up, and we are going to have 2 carbons up top.2691

    This is the shape of our product.2702

    Now, let's number our carbons: right here is the 6-membered ring that was formed: 1, 2, 3, 4--so carbons 1 and 4...here is the 2-carbon bridge above that got pushed up, and then 1 and 4 are now connected to 5 and 6.2704

    On 6, we have our two positions; and where are we going to put that aldehyde group?--are we going to put it on the top or the bottom?2724

    We are going to put it down here, because that is the endo position.2732

    Make sure you always draw in the hydrogen, because otherwise, if you kind of draw it all out in the side, it might be ambiguous whether it's exo or endo.2739

    So, always draw in the hydrogen; kind of like when we did axial and equatorial on a cyclohexane, it is always a good idea to draw in the hydrogen, not just the substituent.2745

    OK, what else is missing on this?--something else is missing.2753

    Remember, our mechanism always has this π bond moving; so between the middle two carbons of the diene will always be a remaining π bond.2756

    This is our product: now, what is interesting about this product--one last thing about it--is: we have just drawn a chiral product.2769

    It is impossible to draw a chiral product and just have a single chiral product after starting with achiral starting materials.2775

    What we always want to remember is that you will always have an enantiomer formed with a chiral product (so in other words, a racemic mixture, a racemate).2786

    Now, what does the enantiomer look like for this?--well, if we drew our same product with that same orientation, and we still need to have the endo electron withdrawing group, but if we chose to put it on this carbon instead, that would also be the right answer: it is actually the enantiomer of this.2798

    Now, if we rotate them around, hopefully you can see that mirror-image relationship that we know exists for enantiomers.2826

    OK, but I just want you to keep that in mind: when maybe you draw one product, and you check your answer, and you see a different product drawn, it might be both the right answer; they are just different enantiomers that are formed.2832

    It doesn't matter if we just flip this over; that could also react, and that would just form the enantiomer; and both of those are just as equally likely to happen, so we are going to get a 1:1 mixture, a racemate.2844

    Let's talk, next, about the stereochemistry of the Diels Alder reaction.2861

    Now, we already talked a little bit about stereochemistry for those bicyclic cases; we saw that endo is the major product.2864

    OK, the other issue about stereochemistry is that the stereochemistry of your dienophile is retained.2871

    We also talked about how, if you form a chiral product, it is going to be formed as the racemate.2878

    OK, but let's see an example where the dienophile has some stereochemistry; and this is an example...where we have this ester and this cyano, we can see that those two groups are cis to one another in the starting material.2883

    So, when we draw our product, let's draw our two bonds that we are forming; number our carbons: 1, 2, 3, 4, 5, 6; go ahead and do our mechanism, since it's so quick and easy--just concerted mechanism.2897

    OK, 1, 2, 3, 4, 5, 6; we have a double bond between 2 and 3, and we have an ester and a cyano to put on 6 and 5.2915

    OK, but what we have to show is: they started out cis to each other; they are still going to be cis in the product.2926

    So, how do we draw a cis when we are looking at a cyclic product--how do we show substituents being cis to one another?2932

    They are going to be pointing at the same side of the ring: so they are both pointing up, or they are pointing down; so, in other words, you could draw them both as wedges, and that is a way of showing that they are still cis.2940

    So, because it is a concerted mechanism and it happens all in one step, the spatial arrangement--the stereochemistry of the substituents remain fixed.2955

    They start out cis, and they end up cis.2965

    Now, I have chosen them both to be wedges; they, of course, could be dashes instead; let's take a look at that product to see if that is the same thing.2968

    What do you think?--is that the same thing--are these two the same molecule or not?2979

    I can't get them to superimpose; and in fact, if I flip this over, I can see their mirror-image relationship; these are, in fact, the enantiomers.2984

    This is another example where, because this product is a chiral product that I drew, I know it can't be the only product; the enantiomer also must be formed.2994

    Now, that doesn't mean you have to draw both every time, but if you draw one chiral product, you have to say "plus enantiomer," or you have to say "racemic."3004

    You have to indicate the fact that this is not the only product that is formed.3012

    OK, so cis means they are both wedges or they are both dashes.3016

    Let's see an example of that: now we have a cyclopentadiene reacting with an ester; here, our groups are trans to each other, so we have to keep that in mind.3023

    We know it is these end carbons of the diene that are going to react; so this looks like one of those bicyclic systems that are going to be formed.3037

    Let's number our carbons: 1, 2, 3, 4, 5, 6.3048

    And we are going to have a 1-carbon bridge, so we're going to have a norbornene-type backbone.3054

    Double bond between the middle carbons; 1, 2, 3, 4, 5, 6; so, in these bridge systems, in these bicyclic systems, the 6-membered ring that we are forming, we are drawing as a boat down at the bottom, and then we are having a bridge (a 1-carbon bridge, in this case) connecting these opposite carbons.3064

    OK, so there is our product; now, how do we draw these ester groups being trans to one another?3084

    They are on 5 and 6; let's draw in our positions of what a tetrahedral carbon looks like--we can draw them trans by putting one in the down position and one in the up position.3092

    Don't forget, hydrogen is in the opposite position; so we could draw one up and one down.3107

    Now remember, we said we like these electron withdrawing groups to be where?--we want them to be in the endo position, the down position, but in this case, we can't put them both in the down position, because they have to stay trans.3111

    So, we get one that is endo and one that is exo, and that is just the way it is; no problem.3123

    The only product is that chiral product that just formed: this actually is a chiral product that has no plane of symmetry, so we want to say "racemic."3128

    Can you envision what the enantiomer would look like?--how could you draw the enantiomer instead (draw a product that is right, but looks different from this one)?3138

    They still need to be trans, but instead of having the front carbon down and the back carbon up, you could have the back carbon down and the front carbon up; that would still be trans, and that would simply be the enantiomer of what we have already drawn.3149

    OK, and finally, how about the regiochemistry of the Diels Alder?3164

    Regiochemistry is when we are looking at which site of reactivity reacts with another site--which site do we react with?3167

    And this is what we are going to have when we have a dienophile that is not symmetrically substituted--a diene that is not symmetrically substituted reacting with a dienophile that is also not symmetrically substituted.3176

    We are going to get two possible products: if we take this diene and this dienophile, and we line them up as drawn, we would get this product.3188

    But if we flip the dienophile over, and we lined up the opposite ends, we would get this product.3196

    This is a question of regiochemistry.3202

    OK, and the rule is that 1,2 product is favored over 1,3; so here, these two groups are 1,2, so this is the preferred product; this is the 1,3, and it is not formed.3205

    1,2 is favored over 1,3.3224

    Notice that I haven't shown the stereochemistry here; and that is kind of an advanced topic--typically we don't worry about it.3227

    It is possible to predict the stereochemical relationship between the group that was on the diene and the group that was on the dienophile, but we usually don't get into that at this level.3234

    OK, so we will just leave it as straight lines now, and assume that all diastereomers are formed.3246

    OK, so one rule is that 1,2 is preferred over 1,3; if we move our substituent here to be at this position, now when we look at the two possible alignments, we get that the two groups can be 1,3 or 1,4 to each other.3252

    The rule there is that, again, 1,3 is disfavored; this is not formed--the 1,4 is favored instead; this is the major.3270

    The 1,2 product and the 1,4 product are the major products; now sometimes, some books call it ortho-like and para-like; I don't like using those terms, because we are not dealing with benzene rings.3283

    OK, but the two groups will either be 1,4 to each other or 1,2 to each other; that is going to be better than 1,3.3294

    Now, why is that--what is going on here?3303

    Again, this is a pretty advanced topic, and so a complete discussion of this and an explanation of why we get this observed regiochemistry has to do with molecular orbital theory.3306

    So, you really need to look at the orbitals that are involved--the orbitals from the diene that are interacting with the orbitals of the dienophile--and you need to have them line up just right, and have their symmetries conserved, and so on.3317

    OK, so without going into a complete, lengthy discussion on that, I'll just kind of refer to that slightly.3331

    The diene is the part that is your nucleophile, that has...you look at the molecular orbitals, and the highest occupied molecular orbital (we call that the HOMO), and that is going to be interacting with the lowest unoccupied orbital (called the LUMO) on the electrophile (the dienophile).3341

    That is the interaction that you want to make as good as possible.3365

    OK, on certain cases, we can predict that, and we can explain it, even without looking at the MO theory; and those are cases that involve resonance.3371

    So, let's do that for a few examples.3380

    Here is an example: if you look at a methoxy substituted diene, and you consider the resonance...we know that this is an electron donation group, so let's go to this resonance form.3382

    We know that this is a contributing resonance form to this diene; and, when we look at this dienophile with an aldehyde here (an electron withdrawing group), we know that it has resonance; and this is a contributing resonance form.3399

    When you consider lining these two up, it is not random how they are going to line up.3414

    On the previous slide, it kind of looked like, "Well, we could put it this way, or we could put it this way"--it seems kind of 50/50; but when you really look at the reactivity of the substrates, you see that what you want is the diene with its partial minus...and right here, you want that lining up with the dienophile and its electron withdrawing group, so that you have the best nucleophile, the most nucleophilic site, joining up with the best electrophile, the most electrophilic site.3420

    It is not random how they line up; and when you look at the molecular orbital diagrams, it is not random how they line up.3455

    When you look at the molecular orbitals themselves, it is not random.3462

    This is the product we are going to get, which would lead, in this case, to a 1,2 substituted product; and that is what we predicted to be major.3465

    Our predictions work very well; and there are a few ways you explain it, but when it comes to resonance, you can use resonance theory to explain it quite nicely in certain situations.3477

    OK, let's take a look at several examples: how about this one?3488

    Let's consider both the regiochemistry of the reaction (in other words, do we line them up as shown, or do we flip them over and line up the other ends?) and the stereochemistry of the problem.3491

    There is a lot to be involved with here.3503

    Well, here is the interaction that we have; and again, don't be tempted to just connect them as drawn; we might need to flip one of them over before we connect them.3508

    OK, but right away, I see something that is confusing, because I know that, for the regiochemistry, I want 1,2 product or 1,4 product, but I have a group on my diene--but I have two groups on my dienophile!3519

    What am I comparing the position of this methyl group...what am I comparing it against when I decide if it is 1,2 or 1,4?3538

    OK, so now I want you to look at those two groups that are on the dienophile: you have a methyl and you have a cyano.3545

    Which of those two groups do you think is going to be more influential in guiding the regiochemistry of the problem?3550

    Which one will have a bigger impact, and more of an interaction with this π bond?3557

    Certainly it is the electron withdrawing group that has the resonance and has the bigger impact; so the electron withdrawing group controls the regiochemistry.3563

    If I were to line it up as drawn, what kind of regiochemistry would I get?--I would get 1, 2, 3--I would get 1,3 as my product.3576

    So, what I am going to do is: I'm going to flip this over; I'm going to put the cyano down here and the methyl up here.3586

    And when I flip it, I want to make sure that I keep my groups trans to each other; I need to keep them trans.3594

    It doesn't matter whether you have it this way or this way; it doesn't matter whether the cyano is on the left or right; but they still have to be trans, because that is going to be important.3600

    Now, I'm going to bring these two together: 1, 2, 3, 4, 5, 6; 1, 2, 3, 4, 5, 6; numbering the carbons is so important, so that you can track all of your substituents properly.3608

    Double bond between 2 and 3; I have a methyl group on carbon 2--that is going to be planar, because it's on a double bond; and then, on 5 and 6, I have a cyano and a methyl--they started out trans; they are still going to be trans.3624

    This cyano group on carbon 5--is it going to be a dash or a wedge?3638

    It actually doesn't matter--you can pick one: let's make it a wedge; that is fine, but if I make it a wedge, that means my methyl group on carbon 6 has to be a dash; it has to be the opposite.3645

    We have to have one up and one down; that is going to be trans.3654

    So, of course, you can pick the cyano to be a wedge or a dash, because that would be drawing one enantiomer or the other.3659

    Let me just draw both, so we can see what they look like--right?3666

    If I drew this as a dash, then my methyl group would have to be a wedge, and so we still have trans.3670

    We have a racemate here, as usual, because we have drawn a chiral product in this case.3678

    OK, let's take a look at this interesting problem: it says, "Explain why no Diels Alder reaction takes place in this case."3688

    OK, I have a diene...what are the components you need for a Diels Alder?--I have a diene; I have a conjugated diene, so that is good; I have something that could be a dienophile--does this look like a good dienophile?3697

    Here is a double bond--that makes it a potential dienophile; and what does it have attached?--it has two carbonyls.3709

    This is actually a great dienophile--so what is the problem?3714

    If you went to try and do this reaction, what would you have to do?3719

    Well, remember, we have always lined up the ends of the diene and the ends of the dienophile in order to predict the product.3725

    So, what we would want to do first is: we would want to rotate this to get in the s-cis conformation.3730

    OK, it has to be in the s-cis conformation to do the Diels Alder.3737

    But here is the key: what does t-butyl stand for?--t-butyl stands for tert-butyl; and so, what happens is: once you rotate it, that brings those two tert-butyl groups toward each other and forces them to be coplanar and allows steric hindrance to interfere here.3740

    OK, it is impossible for these to be coplanar, because the bulky tert-butyl groups keep twisting it out of the plane to avoid the steric interactions.3763

    Sterics prohibit the s-cis conformation.3774

    And, without an s-cis conformation, there is no Diels Alder.3783

    OK, this is another interesting Diels Alder reaction, because it starts with, not an ordinary diene like cyclopentadiene or butadiene; it starts with anthracine.3790

    Anthracine has, built in it, a diene--1, 2, 3, 4; and normally, we say, "Wait a minute; this is an aromatic compound; aromatic compounds do not behave as normal alkenes."3802

    OK, but anthracine will do this reaction, and we will see why in just a second.3817

    Let's try and draw this product: now again, we are going to have to imagine...let's keep this in the plane; let's bring in the dienophile from the top here.3821

    I'm going to take that middle 6-membered ring and spread that out into the bottom.3833

    This is going to be 1, 2, 3, 4, and we are adding 5 and 6 up here; so we are going to look at it in a slightly different point of view, just so we can keep these benzene rings down here.3841

    On this carbon, we have a benzene ring; and on this one (let's bring this in here--let's see if we can do that without making a huge mess), we form this bond.3857

    And when you do your arrows, you see that we move the π bond to be between carbons 2 and 3.3871

    Look what it gives us: after it does the Diels Alder, we still have two aromatic rings left over.3884

    We have lost very little aromatic resonance.3892

    OK, we used to have three aromatic rings, but after forming these new carbon-carbon bonds, we still are left with two benzene rings, which is still very good.3903

    And remember, we formed new carbon-carbon bonds, which is always a good thing; so it turns out that this is a favorable reaction.3914

    Anthracine is a very interesting dienophile to use, and it is good to get some practice and see some examples there, and to understand why, in this case, it might be OK to do the Diels Alder, because we still are able to keep two of those benzene rings intact.3920

    OK, and finally, let's look at a synthesis example that utilizes a Diels Alder reaction.3940

    I'm thinking I might utilize a Diels Alder reaction, because my target molecule has one of these bicyclic systems that we have seen being made from Diels Alder reactions.3946

    Our instructions are to synthesize this from starting materials with no more than 5 carbons; so it gives us some guidance as to how much we have to disconnect this molecule.3956

    Now, first of all, I see an epoxide in the target molecule; so let's do a retrosynthesis asking what starting materials I need.3968

    And what reaction have you seen that makes an epoxide--what functional group did you have initially that could be converted into an epoxide after?3980

    How about a double bond?--if I had a double bond here, then I could convert that to epoxide--do an epoxidation reaction.3991

    OK, and that is cool, because now this gives me my norbornene type structure--remember, that double bond is part of the Diels Alder product.4004

    The question here is, "How do you do a retro Diels Alder?"4014

    That is another skill that you can develop when you are learning about the Diels Alder reactions.4018

    So remember that these two carbons--the bridgehead carbons--used to be the end carbons of the diene.4023

    Here is the 5-membered ring that...this came from cyclopentadiene: 1, 2, 3, 4 carbons, plus this extra bridge.4030

    Those reacted with these two carbons (5, 6); so we can break...these are the two bonds that were formed in the Diels Alder; these are the two bonds we can break to do the retro Diels Alder.4039

    We can even use our arrows, starting with the π bond of the 6-membered ring.4052

    We can even use our arrows (2, 4, 6) to do the retro Diels Alder, because that can help us track the electrons around.4056

    See, we are breaking this bond now; we are breaking this bond.4063

    And so, what do we end up with as our starting material?--we get cyclopentadiene, and we get a 2-carbon dienophile with an ester group.4067

    That would be a very good dienophile; this would be a very good diene; this would be a great Diels Alder.4080

    So, our synthesis is simply taking cyclopentadiene and reacting it with the dienophile and some heat; that will do the Diels Alder.4085

    OK, this is racemic: notice, it says "racemic" here; so I'm not just getting the ester at this position--I'm also getting the ester at this position.4096

    OK, and then, what do I have to do to get to my target molecule--how do I epoxidize a carbon-carbon double bond?4105

    I need some kind of oxidizing agent: it is going to be mCPBA: you need some kind of a peroxide to do that oxidation.4113

    So, that is what gives the target molecule.4124

    Diels Alder: a very important reaction synthetically, and just the one of paracyclic reactions that we will be studying; and it is one of the examples of a type of reaction that the class of compounds of conjugated dienes can undergo.4128

    That wraps it up for the conjugated dienes lesson.4145

    I hope to see you again soon at Educator.com.4149