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Dr. Laurie Starkey

Dr. Laurie Starkey

Acid-Base Reactions

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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 (79)

1 answer

Last reply by: Professor Starkey
Tue Mar 24, 2015 8:18 AM

Post by Sam Zanone on March 23, 2015

Good Morning Dr. Starkey,

I am currently enrolled in Advanced Organic Chemistry and using your amazing lectures to review the basic organic chemistry that I have not used for two years!  Anyways, here is a question that I feel compelled to ask:

When discussing acid/base chemistry in general organic chemistry, we never mention the ultra-low and ultra-high pKa acids and bases (my professor calls them Super-Base's/crazy-weak acids).  Why are these never brought up in basic organic chemistry, even briefly?  

Thanks!

1 answer

Last reply by: Professor Starkey
Sat Feb 21, 2015 11:27 PM

Post by Saadman Elman on February 20, 2015

Hi Professor, Starkey. Hope you remembered me. It was a great lecture and it helped me a great deal. Thank you so much. I really don't have any question but i would like to make an interesting point. As i told you before that i signed up in educator.com 1 years ago and was taking general chemistry with Dr.OW. I figured that every professor has slightly different way to explain certain (gray)areas. I literally write down every single thing that u write and listen to your lecture before going to my class. You were explaining periodic trend for acidity (21:29) regarding which one is more acidic, HF, HCL, HBR, HI. You gave a very good justification why HI is the most acidic comparing to others and why HF is least acidic. My professor was going over the same topic in the class and asked us which one do we think is more acidic. I told him exactly what you said in this video. He said i made a lot of good points but he is not totally convinced. His logic regarding why HI is the most acidic is the following--- ''1)HI Has poor overlap, {As H has 1s orbital and I has 4p) 2) HI Has long bond, the longer the bond the easier it breaks and faster it ionizes than all others (HF,HCL,HBR) 3) Since, I- is larger so it can handle the (-) charge better, making it more delocalized.'' You made the last point in the video which he agrees.

1 answer

Last reply by: Professor Starkey
Tue Nov 11, 2014 12:13 AM

Post by Parth Shorey on November 10, 2014

Considering the factors that contribute to acidity, I don't understand how the middle one is not the most acidic. At 48:30 the inductive effect had the most stability but then again the aromatic compound had the resonance upper hand. How do I know which factor counts more?

1 answer

Last reply by: Professor Starkey
Sun Nov 9, 2014 10:09 PM

Post by Lalit Shorey on November 9, 2014

At 9:22, I don't understand how you determine what is acid or what is base besides using a Pka. Both show octet and lone pair. For some reason my prof won't give us a Pka table so what are other ways in this scenario?

1 answer

Last reply by: Professor Starkey
Fri Apr 25, 2014 12:18 AM

Post by Gina Weiland on April 24, 2014

Does anyone know any tips on figuring the pH ooh and oh of acid base reactions using logs?

2 answers

Last reply by: lakshmi tatineni
Sun Jan 5, 2014 12:30 PM

Post by lakshmi tatineni on January 2, 2014

I do not understand the importance of the lone pair on N and protanation?

1 answer

Last reply by: Professor Starkey
Sat Nov 30, 2013 1:39 AM

Post by John K on November 29, 2013

In the 3rd acid base example, why didn't we take conjugate acid to find out the strongest base?

1 answer

Last reply by: Professor Starkey
Sat Nov 30, 2013 1:42 AM

Post by John K on November 29, 2013

H20 is lewis base right? Then in Acid-Base equilibrium how did it become an acid?
thanks.

1 answer

Last reply by: Professor Starkey
Thu Nov 21, 2013 11:43 PM

Post by richa acharya on November 19, 2013

I'm not able to load any of the videos ever since I cancelled to extend the subscription however I thought I would be able to look at the videos till end of the month. I don't know how it works who should I talk to? I'm lost.

1 answer

Last reply by: Professor Starkey
Tue Oct 15, 2013 8:04 PM

Post by brandon oneal on October 15, 2013

Why didn't you add a plus charge to the oxygen for CH3CH2O(Resonance Effects Acidity)?

1 answer

Last reply by: Professor Starkey
Sun Sep 29, 2013 11:43 PM

Post by Ardeshir Badr on September 29, 2013

at around 3:00 why does AlCl3 only want 3 bonds and therefore with a - sign. and why does NH3 want 5 bonds and therefore has a + sign? please help!

1 answer

Last reply by: Professor Starkey
Sun Sep 15, 2013 9:13 PM

Post by Riley Argue on September 15, 2013

You are an excellent professor.

1 answer

Last reply by: Professor Starkey
Wed Sep 11, 2013 11:09 AM

Post by Frank Ofori-Addo on September 10, 2013

does the carbon that is found in the middle of the product of the second example have any formal charges? if no please state why. thanks.

1 answer

Last reply by: Professor Starkey
Sun Sep 8, 2013 1:19 PM

Post by Atreya Mohile on September 8, 2013

Is there any formula, that determines the number of resonating structures of a particular compound?

3 answers

Last reply by: Professor Starkey
Sun Sep 8, 2013 1:23 PM

Post by Atreya Mohile on September 5, 2013

As mentioned in lecture, that conjugate base of water, i.e. OH, is most stable, because O is more electro-ve, and has a higher capacity to hold -ve charge.. But if we apply the same rule to HX(X=halogens), their conj. bases give inverse of the real phenomena. So my question is that is this concept limited to periods of the periodic table only? Isn't it applicable to groups?

1 answer

Last reply by: Professor Starkey
Tue May 28, 2013 5:13 PM

Post by Tribhuwan Joshi on May 28, 2013

I know that this lecture isn't the correct place for this, but can you please tell me what the calorific value of methyl-propanol is?

Thanks a ton,
Piyush

1 answer

Last reply by: Professor Starkey
Fri May 10, 2013 8:42 AM

Post by Stephanie Bule on May 9, 2013

Professor Starky, on the energy diagram when you said that OH- was the least endothermic, what did you mean? I thought that low energy is more endothermic. I'm a little confused
Thank you!

1 answer

Last reply by: Professor Starkey
Sun Jan 27, 2013 12:30 AM

Post by Yao Mu on January 26, 2013

So if some compound has OH group that this compound can be acidic, as you mention in resonance effects on acidity, then why OH- always act as base.like NaOH?

1 answer

Last reply by: Professor Starkey
Sat Jan 26, 2013 9:43 PM

Post by marsha prytz on January 24, 2013

Dr Starky I was wondering how you come up with the energy table? I don't quite get how you know these molecules/CB have a particular level of energy.

0 answers

Post by Mori Jonata on October 27, 2012

you are right, i need to learn the name. Thanks

2 answers

Last reply by: Mori Jonata
Sat Oct 27, 2012 11:28 PM

Post by Mori Jonata on October 20, 2012

hello professor Starley. can u please explain how we get the negative charge on the nitrate ion (NO3-) and moreover, why do we have the same charge of the nitrite ion (NO2-). Thanks for you help

0 answers

Post by Mori Jonata on October 20, 2012

Thanks. appreciated

1 answer

Last reply by: Professor Starkey
Fri Oct 19, 2012 10:56 AM

Post by Mori Jonata on October 18, 2012

Dr Starkey, is educator.com for university student or just secondary school?

1 answer

Last reply by: Professor Starkey
Wed Oct 3, 2012 10:19 PM

Post by Mori Jonata on October 3, 2012

Thank you Dr starkey for the quick reply. I will recommend this website to a friend.

1 answer

Last reply by: Professor Starkey
Wed Oct 3, 2012 10:19 PM

Post by sophia lin on October 3, 2012

is that the resonance on the C.B always contribute the large amount to the stability?

1 answer

Last reply by: Professor Starkey
Tue Oct 2, 2012 11:30 PM

Post by Mori Jonata on October 1, 2012

How does the C in CHO pull electron toward itself. i thought O is more electronegative more than C and it should be pulling the electrons not the C. thanks

1 answer

Last reply by: Professor Starkey
Tue Oct 2, 2012 11:29 PM

Post by Mori Jonata on October 1, 2012

and moreover, which of the pull electrons toward theirself? is it the N in N02 or the O in N02. because i can see that the O in N02 has negative charge.

1 answer

Last reply by: Professor Starkey
Tue Oct 2, 2012 11:29 PM

Post by Mori Jonata on October 1, 2012

Hello professor Starkey, can you please explain the lewis structure behind the N02 of the topic (Inductive effect on Acidity). how do we get + charge on the nitrogendioxide(N02) and the one on cyni ion(CN)

1 answer

Last reply by: Professor Starkey
Tue Sep 18, 2012 10:44 AM

Post by Hawa Muse on September 15, 2012

how do you know which is a base and which is an acid?

1 answer

Last reply by: Professor Starkey
Thu Apr 12, 2012 11:31 PM

Post by Susan Barrett on April 11, 2012

I like how Professor Starkey used people as an example it really helped me remember and think of them as something more

2 answers

Last reply by: Professor Starkey
Sun Nov 25, 2012 12:15 AM

Post by ochemstarkey on April 10, 2012

Is there a way to skip to a certain section of the video?

1 answer

Last reply by: Professor Starkey
Sun Nov 20, 2011 9:19 AM

Post by WaiYee Hon on November 11, 2011

I m confused , so F is the most electronegative , why negative charge on F is not the most stable when comparing with Br- CI- or I- ?

3 answers

Last reply by: Professor Starkey
Mon Oct 15, 2012 9:49 PM

Post by Jindou Tian on October 11, 2011

Does this course only cover the material of the first semester of Organic Chemistry?

1 answer

Last reply by: Professor Starkey
Sun Sep 25, 2011 7:27 PM

Post by Bianca Williams on September 18, 2011

Is the size of the atom more important than the electronegativity of the atom when studying inductive effects? For example, if you had two molecules that deprotonated leaving I- and O- (and the rest of the molecule is the same for both), which of the two ions is going to have a stronger inductive effect?

1 answer

Last reply by: Professor Starkey
Fri Sep 9, 2011 11:34 PM

Post by Kangoma Kindembo on September 3, 2011

How can an element be known as the most electronegative by just looking at it? Does it depend on their emplacement in the periodic table?

1 answer

Last reply by: Professor Starkey
Wed Aug 17, 2011 3:44 PM

Post by Tej Jai on August 3, 2011

You said that CF3OH has a parent acid that is stronger (not Cf3Oh itself, but the parent acid). You also mention that CF3OH is a weaker conjugate base. So, how can it be a weaker conjugate base and a strong acid at the same time?

0 answers

Post by ochemstarkey on January 26, 2011

Awesome videos. Helpful in inductive effect.

Acid-Base Reactions

Draw the product and then determine the direction of the equilibrium:
  • Equilibrium lies in the direction of the weaker acid/bas pair
Equilibrium lies to the right and favors the products
Draw the product of this acid-base reaction:
Draw the product of this reaction:
Rank these compounds in order of increasing acidity:
CH3CH2CH3, CH3CH2OH, CH3CH2NH2
CH3CH2CH3< CH3CH2NH2< CH3CH2OH
Rank these compounds in order of increasing acidity:
HCl, H2O, H2S
  • HCl vs. H2S
    Acidity increases across a row so H-Cl bond is more acidic
  • H2O vs. H2S
    Aciditiy increases down a column so SH bond is more acidic
H2O < H2S < HCl
Rank these ions inorder of increasing basicity:
CH3, HO, Br
  • Increasing acidity of conjugate acids:
    CH4< H2O < HBr
Br< HO< CH3

*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

Acid-Base Reactions

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

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

Transcription: Acid-Base Reactions

Welcome back to Educator.0000

Next we are going to talk about acid-base reactions or proton-transfer reactions.0002

Let me show you an outline of the topics we are going to be talking about.0009

First we'll discuss the different definitions we have for acid-base reactions.0012

Then we are going to talk about several things that can have an impact on the acidity of a given molecule--look at trends in the periodic table, inductive effects, resonance effects.0017

We will wrap up by looking at some common acids and bases.0027

Most students coming through general chemistry, having a year of general chemistry, will know that there is two main definitions for acid-base reactions.0032

That is having Lewis acids and bases and Bronsted-Lowry acids and bases.0039

A Lewis acid is something that is described as an electron pair acceptor; so this has to do with electrons; we describe this as an aprotic acid.0044

We will find that the other type of acid, the Bronsted-Lowry, is one we call a protic acid; we will see that next.0056

How can something accept a pair of electrons?--well, it is something that will have a vacancy; that has no octets.0062

Some common Lewis acids are things like BF3 or AlCl3.0070

These molecules, when you take a look at their detailed Lewis structure, you find that there is a vacancy on this bond; it is missing an octet.0076

Same thing with the aluminum; it has only three bonds; and we know that atoms want to have a filled octet; and they would readily accept a fourth bond.0088

That is what makes them electron pair acceptors and excellent Lewis acids.0097

A Lewis base then is something that can donate a pair of electrons; so something with either a lone pair of electrons or maybe a pi(π) bond--these would make very good Lewis bases.0103

Let's see an example--if we reacted ammonia (NH3) with AlCl3.0113

We said AlCl3 would be a good example of an acid--a Lewis acid; I'm going to put this in quotes because it's a Lewis acid.0118

Ammonia would be a good example of a base because it has a lone pair of electrons.0126

The reaction e would expect to have happen between these two is that the nitrogen would share its lone pair of electrons with the aluminum and form a bond.0131

We are going to form a new bond between nitrogen and aluminum; and this would be our product of this Lewis acid-base reaction.0140

Because of this new bond, we are going to have some formal charges now on the nitrogen and the aluminum.0149

This nitrogen has one, two, three, four electrons around it; we know nitrogen wants five; so this nitrogen now has a positive charge.0156

This aluminum also has one, two, three, four electrons around it; but aluminum only want three; so it has an extra electron; and we would have a negative charge on the aluminum.0165

So this is the product of our Lewis acid-base reaction.0177

Let's just take a look at one more example--a carbocation is another good example of a Lewis acid; because it is missing an octet and can accept a pair of electrons.0184

Water could be used as a Lewis base; and so same idea--we could use that lone pair to form a bond between the oxygen and the carbon.0196

What does our product look like?--we now have a new bond between carbon and oxygen; and what does this oxygen still have on it?--it still has two hydrogens.0206

Any lone pairs?--well, one lone pair is now being used as a sigma (σ) bond; the other lone pair is still there; so this would be the product of this second reaction.0219

Again, let's check our Lewis structure and check for formal charges; this carbon now has four bonds so it is neutral.0231

But this oxygen has one, two, three, four, five electrons; we know oxygen wants six; it has only five so it is missing an electron; so we would have this positive charge here.0237

These are a few examples of some Lewis acid-base reactions; but in organic chemistry, we typically don't refer to such reactions as acid-base reactions.0248

We are going to have a new name for Lewis acids; we are going to call these electrophiles--things that love electrons; and we are going to call Lewis bases nucleophiles.0257

We will see reactions like this down the line further down in our lessons; but when we do so, we are not going to be calling them Lewis acids and bases necessarily.0272

We are going to be describing them as electrophiles reacting with nucleophiles.0284

For organic chemistry, when we are discussing acid-base reactions, we are talking about the other definition--the Bronsted-Lowry type.0289

In a Bronsted-Lowry definition, a Bronsted-Lowry acid is an H+ which we call a proton; it is an H+ donor; it should be a Bronsted-Lowry acid.0297

That is why we call this kind of acid a protic acid; because it is one that donates protons; that is a source of protons.0314

A Bronsted-Lowry base is a proton acceptor--something that can take a lone pair of electrons.0324

The reaction--an acid-base reaction then can be described as a proton transfer; a transfer from an acid to a base.0337

The mechanism for that transfer is not the hydrogen atom flying over to the base; because our mechanism when we use curved arrows is showing electrons moving.0346

Instead, it is the lone pair of the base or whatever electron source the base has.0360

It is the lone pair attacking the proton and then breaking the H-A bond and having those two electrons go to the remainder of the acid structure.0366

Our product then will now have the base with a new proton on it and the A group with a new pair of electrons on it.0376

Now we have both the base and the acid were neutral as shown.0387

The base, after you add a proton to it--after you add an H+, will now be positively charged; and the A, after losing an H+, will be negatively charged.0391

You will have these charges if we started out neutral in both cases.0401

After a base has accepted a proton, we call that new structure the conjugate acid of that base; so a base is related to its conjugate acid by protonation.0407

The structure that remains after an acid has lost its proton is known as the conjugate base of that acid; so an acid is related to its conjugate base by losing a proton or donating a proton.0420

This is called a proton-transfer reaction; and what we have here as shown is an equilibrium.0435

We have two acids and two bases in competition on who is going to donate the proton and who is going to accept the proton.0442

Because if you look at this reverse reaction, the reverse reaction would also be described as a proton-transfer reaction, right?0448

This now is a proton donor, and this is a proton acceptor; and these products would be the result of a proton transfer.0454

We have a competition for this equilibrium; and the rule is that the equilibrium lies in the direction of the weaker acid-base pair... the weaker acid base pair.0462

This is an important rule to keep in mind; we will see lots of examples of this as we move along.0486

If this equilibrium lies in the direction of the weaker acid-base pair, we are going to have to be able to determine which pair that is.0496

How do you decide who the stronger acid is?--well, if you are lucky enough to have a pKa table, you can use that.0504

Or perhaps you can predict that yourself; and that is what we are going to be focusing on in this lesson.0510

That is looking for features that affect the acidity and make something a stronger acid or a weaker acid.0515

Here is an example--let's say we have water acting as an acid and ammonia acting as a base; let's see what that proton-transfer reaction would look like, OK?0521

The acid donates one of its protons to the base; so our mechanism is the base grabs the hydrogen and leaves the electrons behind on the oxygen.0530

What does water look like after it has been deprotonated or has donated a proton?0541

We will now have HO with three lone pairs; and that means we have an O---one, two, three, four, five, six, seven; oxygen only wants six; so we have an extra electron there.0547

That is the conjugate base; and what does the conjugate acid of ammonia look like?--it is, instead of NH3, it is going to be NH4.0560

You could just draw it as NH4 or I can draw it out to show the new hydrogen for emphasis.0568

That is also going to be charged; this nitrogen has one, two, three, four bonds--four electrons; it wants five; so this is going to be N+; we are going to get this ammonium NH4+.0573

If we take a look at this equilibrium and ask in which direction does the equilibrium lie?--does it lie in the forward direction or the reverse direction?0587

What we can do is we can look up the pKa's of the two competing acids; and the forward reaction, water, that has a pKa of about 16.0595

In the reverse reaction, the ammonium is the acid and that has a pKa of about 9.0604

What is the relationship between pKa and acidity?--they have an inverse relationship--the lower the pKa, the higher the acidity.0610

Let's remember that--the lower the pKa, the higher the acidity, and the stronger the acid; so a pKa of 9 is a stronger acid, and a pKa of 16 is a weaker acid.0619

Where does the equilibrium lie?--it lies in the direction of the weaker acid-base pair; so it is going to be going from the stronger acid to the weaker acid.0641

The equilibrium lies to the left--this is one way to describe that; you could also say that the reverse reaction is favored; and we can make that conclusion simply by comparing the two acids.0650

We said that it is going to be the weaker acid-base pair; and it turns out that once you identify who the stronger acid is, that is also going to tell you something about the conjugate bases.0674

If ammonium has a pKa of 9, this is the stronger acid; its conjugate base is going to be the weaker conjugate base.0687

Because an acid and its conjugate base also have an inverse relationship--a stronger acid has a weaker conjugate base; the weaker acid, water, has the stronger conjugate base.0701

Once we identify the weaker on one side of the acid, it will always correspond with the weaker base being on that same side.0716

We don't have to compare both the acids and the bases; we just need to find a difference in one or the other and that should be enough to answer our question.0725

We can just kind of mention here: the stronger acid has the weaker conjugate base; and the weaker acid has the stronger conjugate base; so you can see how we ended up labeling those two bases.0736

This is how we can decide the direction of an acid-base equilibrium.0755

Let's take a look at some factors that might affect the acidity, the strength, of an acid.0761

One thing we can do is we can look at the periodic trends; let's take a look across a row of the periodic table.0767

Carbon, nitrogen, hydrogen acids--all of these have hydrogens on them; so they can possibly donate a proton; they could be potential acids.0772

Given are the pKa's: methane CH4 has a pKa of about 50; ammonia has 38; and water has about 16.0783

Who is our strongest acid here?--the lowest pKa is the strongest acid; and the pKa of 50 is the weakest acid.0790

Let's make a quick note about pKa's; let's take a look at the difference here; 50 to 16--that is a difference of 34 pKa units.0805

Does that mean that water is 34 times more acidic than methane?--that would be pretty significant.0816

But, no--remember that the pKa table is a logarithmic scale; so we are looking at orders of magnitude--factors of 10.0825

There is a one with 34 zeros after it... times more acidic; so that is a like gajillion--we don't even know what that number is; so this is hugely, hugely more acidic.0834

We need to be able to understand that; we need to be able to rationalize that and have an understanding for these pKa's.0851

The way we are going to answer the question of why is there such a huge difference in their pKa's when you go across the row in a periodic table?0857

What we are going to do is we are going to look at the conjugate bases of each of these... look at the conjugate bases.0865

If water acts as an acid, what is the conjugate base going to be?0874

We are going to lose an H+; that is going to give hydroxide, HO-, as a conjugate base.0878

How about ammonia?--ammonia has one lone pair of electrons; so after we lose an H+, we will have NH2 now with two lone pairs; also a minus because we are losing an H+.0886

Methane CH4--we can see a trend here; we will now have a CH3 with an extra lone pair and a negative charge.0899

These are our three possible conjugate bases; and what we want to do is try and look for a difference in their stability.0908

What is the most significant difference as you move across the row on a periodic table?--you are going to be increasing in electronegativity.0915

Oxygen is the most electronegative atom compared to carbon and nitrogen; and what effect is that having for us?0923

Let's start by writing the fact here--oxygen is more electronegative than the others.0929

Is that a good thing for that negative charge to be on a more electronegative atom?--absolutely; so what we can say is that the oxygen better handles the negative charge.0941

That means that hydroxide is the most stable conjugate base; hydroxide is the most stable of these three species--the C- versus the N- versus the O-; this is the most stable.0957

What is the relationship then between stability and reactivity?--well, the more stable something is, the lower in energy it is; the less reactive it is.0976

Because it is more stable, hydroxide is the weakest conjugate base; it is the least reactive.0986

What do we know about something that has a stable unreactive conjugate base?--what does it tell you about the parent acid?--it must be a strong parent acid; so hydroxide has the strongest parent acid.1001

Does that agree with our pKa data?--it sure does; that had the lowest pKa; and yes, water was the strongest acid.1021

OK, so it's going to be the stability of the conjugate base that is going to answer so many questions about the strengths of various acids.1029

Let's go through the opposite argument for over here on why this is maybe not such a great conjugate base.1039

What we can say here is that carbon is the least electronegative of all of these carbon, nitrogen, oxygen atoms; and so this is the least stable conjugate base.1047

If this is the least stable, unstable conjugate base--that means it is the most reactive conjugate base; it is the strongest conjugate base... this is the most reactive, strongest conjugate base.1071

OK, the reactivity... the relationship between stability and reactivity for molecules is very similar to that of people.1094

The more stable you are, the more calm and cool and collected you are; you are pretty unreactive; the same is true for molecules.1104

But if you are high energy and unstable, that makes you very reactive and very volatile.1112

We are going to find that same relationship is true when we are comparing people and when we are comparing molecules.1117

If this one is the strongest conjugate base, what does that tell you about the parent acid?--we know that this has the weakest parent acid.1123

That is what our pKa data tells us: pKa 50--this is a horrible acid because carbon hates having a negative charge; it is so electropositive.1137

Our goal and what this is demonstrating here and what we will find again and again and again is that the stronger acid... the stronger acid has the more stable and therefore weaker conjugate base.1148

One thing that can help stabilize the conjugate base is the electronegativity of the atom on which a negative charge resides.1177

Let's take a look at an energy diagram that might help illustrate this concept.1184

If we are comparing methane and ammonia and water as acids, we know that water is the strongest acid.1190

That is because when we compare the difference in energies of our conjugate bases, we see that the more stable conjugate base is the one with the negative charge on the most electronegative atom.1198

Right here--this is the most stable conjugate base; meaning it is the lowest in energy.1210

How about the energies of our starting materials?--these are all neutral stable molecule; so these have all about the same energy.1221

There is not any significant difference in the energies of the starting materials.1228

The significant difference in energies is the atoms bearing the negative charge.1233

When we compare these processes, which of these would prefer to be an acid and donate a proton?1238

This process looks the most favorable; this is the least endothermic; this is the most favorable reaction; and that is why water is the strongest acid.1246

Once again, we are going to look for differences in the stability of the conjugate bases; the more stable the conjugate base, the stronger the parent acid.1263

What makes an acid a good acid?--it doesn't mind donating a proton if it doesn't mind where it is going to.1270

If it is going to a conjugate base, isn't it a stable happy place?--that makes the parent acid more likely to donate its proton.1277

Let's see another example; another periodic trend is when we're going down a family or down a column on the periodic table; so let's compare HF, HCl, HBr, HI.1287

Here we have our pKa's; so of these pKa's, who is our strongest acid?1300

The lower the pKa, the stronger the acid; in fact, the more negative the pKa, the stronger the acid.1305

HI is the strongest acid; that is stronger than HBr, than HCl, and than HF; HF is the weakest of all the halo acids; let's see if we can explain this again.1311

The way we are going to explain it is if we ask: why do we have this difference in pKa's?1327

Once again, we are going to look at the conjugate bases; so what does the conjugate base of HF look like?1333

That means HF is going to act as an acid; it is going to donate a proton; and that leaves behind F-.1341

HCl gives Cl-; HBr gives Br-; and HI gives I-.1348

Where do we go from here?--we try and find something that will explain a difference in stability between these different conjugate bases.1357

What is the most significant difference as you move down a column in a periodic table?--yes, the electronegativity does change as you move down a column.1366

But a more important difference is going to be the size of the atom as you move down and you add a shell of electrons on each new row.1375

It turns out that iodide is the biggest ion; and fluoride is the smallest ion; so that is the fact; that is the difference between these--all four of these; how do we relate that to stability?1386

Let's think of this ion as having a negative charge; a negative charge tells us we have an excess of electron density.1403

If you can spread that negative charge out over a larger surface area of the large iodide--then that is going to be more delocalized; and that is going to be a more stable charge.1410

What we say about I- is that the negative charge is dispersed or delocalized--that is a very good word.1424

That means it is not in one small location; it is delocalized; it is spread out over several locations; and that means this is the most stable conjugate base.1437

Where do we go from here once we decide which is the most stable conjugate base?--most stable always means less reactive; so this is the least reactive and therefore weakest conjugate base.1453

Now we have something about the strength of the conjugate base; the weakest conjugate base has the strongest parent acid.1473

Does that agree with our pKa?--it does; this had the lowest pKa; so yes, HI is the strongest acid.1487

What would we say about fluoride?--why is fluoride so much less acidic?--so much less likely to donate a proton?1496

Here we have a very, very small surface area with that negative charge; so we could describe this as an intense negative charge--compact, intense; that makes it unstable.1503

It is an unstable anion to be on such a small surface area.1519

If you are unstable, that means you are more reactive; this is the most reactive and therefore strongest conjugate base; and the strongest conjugate has the weakest parent acid.1523

In this case, we can see the size of the atom having an impact on the stability of the negative charge on the conjugate base.1543

Let's take a look at some inductive effects that we might have to explain differences in acidity; if we ask which is the stronger acid here, we have CH3OH versus CF3OH.1554

In this first structure, if we expected this to be an acid, there is two different types of protons that can be donated--one of the hydrogens on the carbon or one of the hydrogens on the oxygen.1566

Which of those hydrogens do you think is going to be the most acidic?1577

We just saw the periodic trends; and we know that because oxygen is so electronegative, that would much prefer to have the negative charge.1581

What we are doing is comparing this OH with this OH when we are comparing the acidity.1588

How are we going to distinguish between these two?--well, once again, let's look at the conjugate bases and see if we can find a difference.1593

CH3OH--the conjugate base would be CH3O-; CF3OH... let's draw out these fluorines because that is obviously the difference between the two molecules.1603

We either have CH3 or CF3; and we have an O- versus an O-.1623

This is a case where periodic trends are not going to help us because the negative charge is on the exact same electronegative oxygen in each case.1629

Now we look elsewhere in the molecule to see if there is something that can maybe stabilize or maybe destabilize the negative charge.1637

Clearly, we have these fluorines here; and so let's think about what effect that is going to have on the negative charge; we will start by stating the fact that we know about fluorine.1645

That, of course, is that fluorine is more electronegative than hydrogen--that is what we are comparing it to in this case; of course, fluorine is more electronegative than everything.1654

But we know that fluorine is more electronegative, and what does it mean to be electronegative?--it means that fluorine pulls electron density toward itself.1668

Let's also state that fact: we have an inductive withdrawal of electron density by fluorine... we have an inductive withdrawal of electron density.1677

We can show that with an arrow like this; we could say that the fluorines... each of these fluorines is pulling electron density toward itself.1698

These arrows show the movement of electrons through these simga(σ) bonds; that is what we call an inductive withdrawal--an inductive effect.1707

Here is the tricky part: is that a good thing for the negative charge or is that a bad thing for a negative charge?1716

Typically, when I survey my students on this question, I get about a fifty-fifty split; let's think about what it means to have a negative charge.1723

A negative charge tells me that there is an excess of electron density on that oxygen; that is not a good thing--it would rather be neutral.1730

What are these fluorines doing?--they are helping to pull some of that electron density away from the oxygen, bringing it closer to being neutral.1739

In fact, you could imagine that each of these fluorines is sort of taking on some of that negative charge; it looks like we are delocalizing that charge a bit.1748

Is that a good thing?--that sounds like a good thing; and that is, in fact; this stabilizes... this stabilizes the negative charge.1757

We could again kind of think of it as delocalizing... it delocalizes it.1776

If this is the more stable conjugate base, what does that tell you?--this is the more stable and therefore less reactive, meaning weaker... this is the weaker conjugate base.1785

The weaker conjugate base--this has the stronger parent acid.1807

That was our original question; our original question--which is the stronger acid?--and the acid with the fluorines on it is going to be the stronger acid.1818

This is more likely to donate its proton because the resulting anion on the conjugate base will be stabilized by the fluorines--the inductive effect of the fluorines.1828

We could describe fluorine as an electron withdrawing group; we can abbreviate that EWG; we are going to be seeing that abbreviation a lot down the road.1838

Let's take a quick look at some other common EWGs (electron withdrawing groups).1847

For example, if we have a nitro group, an NO2 group; I've drawn it out here.1851

This is also something that would pull electron density toward itself; just like a fluorine did, right?1856

We said a fluorine pulls electron density; a nitro would do the same thing because of that N+.1862

A cyano group (a CN triple bond) has the same effect; and even though it is not charged like the nitro...1872

Because nitrogen is more electronegative than carbon and because we have some resonance here, there is a partial minus (δ-) on this nitrogen and a partial plus (δ+) on this carbon.1879

Therefore, this also pulls electron density toward itself; it would be an EWG.1890

And a carbonyl--a carbonyl also has resonance that puts a δ+ on this carbon and a δ- on this oxygen; and so that δ+ carbon causes an inductive withdrawal.1896

We can see it can also do stabilization by resonance.1907

Any halide is going to be electronegative and can pull electron density toward itself; so not just fluorine, but also the others--chloride, bromide, iodide.1913

What these have in common is these would all stabilize an adjacent negative charge... these would all stabilize an adjacent negative charge.1922

What if I had a positive charge next door?--now, we are not going to see that on a conjugate base; but what if I had a positive charge, an electron deficient site here? 3231 Would it be a good thing to have a fluorine on that?--or a nitro or a cyano pulling even more electron density away?--that would be a bad thing.1943

We can make a little note here; and it would destabilize a + charge; that might become important down the road if we ever saw that when we are exploring the effects of EWGs.1958

One thing that we will note about inductive effects is that these are something that decrease with distance.1977

The further away we put that EWG, the less effective it is going to have; because simply there is more bonds to travel through.1983

Inductive effects are looking at the electron in σ bonds being pulled toward a more electronegative atom or electronegative group; and so that is why we see a decrease with distance.1989

If we take a look at these acids, these are all carboxylic acids.2002

We see this group here--a carbonyl with an OH; and that is the group that we are going to have; that is going to be our acidic group--it's the OH there.2008

They all have similar looking conjugate bases where we have an O- next to this carbonyl; so they will all have very similar conjugate bases.2024

The only difference is what is attached to the carbonyl.2035

Here we have just a CH3 group; here we've put a chlorine somewhere down the chain; here we've put a chlorine again; here we've put a fluorine.2039

What do we see as effect on the pKa's?--we see that as soon as we put a halogen on here, we lower our pKa; in fact, this is going to be the most acidic with the lowest pKa.2049

Why is this the most acidic?--well, that is because the fluorine is more electronegative compared to the chlorine; so this has the most stable and therefore weakest conjugate base.2064

That fluorine is going to help stabilize that conjugate base the best, right?--it is going to pull electron density away from the conjugate base.2088

That is going to be a good thing; so this is the strongest acid.2095

Compare that to having a chlorine; that chlorine is making it not quite as acidic.2101

How do we compare these two?--they both have a chlorine, but this one is situated a little more closely to where the negative charge will be on the conjugate base; this one is a little further down.2107

We see, if we have... the EWG is farther away and less effective.2121

While they all pull electron density away, the fact that he is not as close to the O- means that he's not going to have as big an impact on the pKa.2135

Why does this have the highest pKa of all of them?--why is this the weakest acid of all of them?--because this has no EWG.2146

There is nothing there to help stabilize the O- in addition to... they all have the same O-, so there is nothing additional here to stabilize the negative charge that the others have.2155

This has the least stable and therefore the strongest conjugate base; and of course, this is the weakest parent acid.2168

If we have to compare EWGs, the closer we can get that EWG to the charge that we are trying to stabilize, the better.2185

Let's take a look at using resonance to help stabilize a conjugate base and what effect that might have on the acidity.2196

If we take a look at these two OH bearing compounds, these both have OH groups; so those are reasonably acidic.2205

But this one has a pKa of 16, and this one has a pKa of 5; now again, that is eleven zeros; that is a huge difference in pKa; let's see if we can explain where that difference comes from.2215

If we look at the conjugate bases, we are comparing an O- to an O-.2230

Once again, we can't think of any difference in periodic trends because each of those oxygens is equally electronegative.2234

We might say this carbonyl can have some electron withdrawing effect on that oxygen to help stabilize it.2243

But we just that saw inductive effects maybe have an effect of one or two pKa units--certainly not making it trillions times more acidic like this one is; so what is the difference here?2250

If we take a look at this O-, I recognize that this lone pair is allylic; it's next to a π bond which means we can have resonance with that lone pair and that π bond.2262

What does that resonance do?--it moves the negative charge to a new location; anytime you can delocalize the charge through resonance, that is going to be a really great effect.2276

What we can say here is conjugate base 2 is resonance stabilized... resonance stabilized; you can say it is stabilized by resonance.2293

Resonance is always a good thing and will always have a big impact on stability.2309

That tells us that conjugate base 2 is the more stable, weaker conjugate base; and that is why conjugate base 2 has the stronger parent acid by far--a pKa of only 5.2315

So resonance will have a tremendous impact on the acidity of a compound.2342

One thing I want to consider though is you might look at the starting compounds and recognize that even the starting acid has some resonance stabilization, right?2349

Because this also had an allylic lone pair; and there is another resonance form we can draw for this; so you might ask which one of these resonance stabilizations is more significant?2362

The answer here is when you think about which resonance form contributes more to the overall picture, that will tell you how significant the resonance is.2380

Here we have an O-, and here we have another O-; which of these is the better contributor?--which will contribute more to the overall hybrid?2388

The answer is they are equally contributing; and so what we have in the case of this conjugate base is that we have a large amount of resonance stabilization.2400

In fact, when you have two equivalent resonance forms, that is the best stabilization you can have; so this really delocalizes the negative charge.2417

You could put that down here again; this is so important... delocalize negative charge.2425

While this does have some resonance, because now we've created formal charges, the second Lewis structure is avery small contributor to the overall picture.2435

Even though it exists, what we have here is just a small amount of resonance stabilization; and it turns out that this will be not significant.2445

The more significant resonance that clearly does have an impact on the pKa is the stabilization of the conjugate base.2459

Maybe if we take a look at an energy diagram, we might see that pictorially; it might make a little more sense.2470

We said that the stabilization of this parent acid was small, and the stabilization of the conjugate base was large.2478

If we take a look at an energy diagram, when we compare the parent acids 1 and 2, we might that there is in fact a small difference in stabilization because 2 does have a small amount of resonance.2488

But whatever small difference there is, that is not as significant as the large amount of resonance stabilization.2505

That we have comparing the O- in the conjugate base 1 and the resonance stabilized delocalized O- in conjugate base 2.2515

We have a large amount of resonance; so there is a large difference in energy; and so once again, this transformation from conjugate base 2 is the least endothermic and the most favorable.2525

What we are going to be looking for, something to bear in mind, is that the most significant resonance stabilization that we can look for.2541

Of all the resonance that we are looking for is we want to find a way to delocalize the negative charge of the conjugate base; we want to be able to move that conjugate base around.2552

The most significant resonance stabilization is delocalization of the negative charge.2567

If there is a way you can move that negative charge to a different location because of resonance, that is going to be something that will lead you to the correct answer and the correct conclusion.2577

Let's see another example; how about if we compare these three compounds?--again, we are looking at three compounds that bear OH groups.2589

But we are trying to see which of these OH's is going to be most likely to donate a proton and therefore be the strongest acid.2600

Because we are comparing three, let's also try to decide which would be the least acidic; which would be the least likely to donate a proton.2606

As usual, the answer is going to reside, since these are all neutral stable molecules, the answer is going to reside in the structures of the conjugate bases.2613

Conjugate base 1 has this O-; conjugate base 2 has this O-; conjugate base 3 has this O-.2622

What we are going to do is try and find a difference in their stability; do any of these have resonance?--that might be a good thing to look for.2629

This one has some resonance because we have a carbonyl; this has some resonance; we can draw an O-C+; so we have that resonance.2640

Does this one have resonance?--can we take this negative charge, take that lone pair, and move it in here?--would that be a way to delocalize that negative charge and move it around?2656

No, we can't do this; because this carbon already has four bonds; it has no place to move its electrons; so that would just be five bonds; so this has no resonance.2666

This has some; we will see what relevance that has here; and how about this last one; does this have any resonance?2679

If we take a look at these lone pairs, we see that they are allylic to a π bond or next to a π bond; so yes, this does have resonance.2685

We can draw a new Lewis structure that uses one of those π bonds; this carbon now will have a negative charge.2696

Are there any other resonance forms?--there are actually; because this lone pair is still allylic.2708

We can move that in; any time we have allylic resonance, we can make the lone pair a π bond and make the π bond a lone pair.2715

Any more resonance?--yes, in fact, we can continue moving this around; we will just say et cetera here because we have made our point that we can move that negative charge around.2727

When we look at the two possible resonances for conjugate base 2 and conjugate 3, what I see in conjugate base 3 is these resonance forms actually relocate the negative charge.2735

They delocalize the negative charge; so that is going to be excellent resonance.2748

Let's say that about conjugate base 3; We have very good resonance stabilization; and that is because we have delocalized the negative charge.2751

This is most definitely going to be the most stable conjugate base; the most stable conjugate base is the weakest conjugate base.2772

The weakest conjugate base has the strongest parent acid; so this has the strongest parent acid; and so we would expect #3 to be the most acidic.2786

how about if we compare 1 and 2 now; if we are looking for who is the least acidic, is there any difference between 1 and 2?2806

2 has some resonance, but notice it doesn't help to move that negative charge; but is this something that stabilizes the negative charge or is it something that makes it worse?2816

Having a positive charge there would help take some of the electron density away from that oxygen, wouldn't it?2827

In fact, we saw the carbonyl acting as an EWG; and so this in fact would be a good thing for the negative charge.2835

Let's make the point first that the resonance... because it does have a resonance form, but the resonance does not delocalize the negative charge; so it is not as good as conjugate base 3.2850

But the inductive effects of the carbonyl, if it is acting as an EWG, the inductive effects makes it more stable than conjugate base 1.2868

Even though this resonance doesn't help move the negative charge from the oxygen, it helps pull some of that electron density away inductively.2893

The fact that we have an EWG, much like we saw the fluorine doing that behavior, means that this is going to be the second most acidic compound; and then compound 1 is the weakest.2902

Because this has no resonance, this is the least stable and therefore strongest conjugate base; so this has the weakest parent acid; so compound 1 is the least acidic.2916

In this example, we have a combination of both inductive effects and resonance effects.2944

When we have both of those acting like we do in this case, it is the resonance effects that are generally going to win out.2951

Because the resonance effects are going to be ones that really delocalize charge and add stability.2958

How about if we turn it around in looking at an acid-base reaction and try to answer the question which is the stronger base?--same question is asking which is more basic?2968

We are comparing CH3OH versus CF3OH; and how are we going to answer this question?2981

Let's take the same approach we did for the acids; and the acids, we looked at the conjugate bases; so when we are comparing bases, we are going to look at the conjugate acids.2989

In other words, let each of these be a base and see where it takes us; so let's protonate in order to look at the conjugate acids.3001

Just like an acid donates a proton, being a base means that you accept a proton.3017

If we imagine this reacting with some acid, it can take a proton from that acid; so what does the conjugate acid of this base look like?3021

It will now have two hydrogens on that oxygen and just one lone pair; that gives us an oxygen with just one, two, three, four, five electrons; it wants six; so it will give us an O+.3032

If you add an H+ to a neutral molecule, you will end up with a positively charged molecule; so that's conjugate acid 1.3045

Conjugate acid 2, same thing except... this is an oxygen... except instead of a CH3, we have a CF3.3055

Let's draw our conjugate acids; and let's look for a difference in their stabilities; so just like we did for the cases of deciding who is a stronger acid.3067

What is the difference between these two?--well, once again, we see that we have fluorine versus hydrogen.3078

Let's make the note; let's start by stating the facts--fluorine is more electronegative than hydrogen.3083

That means that it withdraws electron density... and it withdraws electron density inductively, right?3097

The effect we have going on is something like this: each of those carbon-fluorine bonds are polar in the direction of the fluorine; it pulls electron density3105

That makes this bond polar as well; and it pulls electron density; it is an EWG.3118

Here is the question: is that a good thing or a bad thing?--in this case, we are looking at a positive charge.3126

That tells us that this oxygen is electron deficient; it is missing electrons.3132

What are those fluorines doing? they are pulling even more electron density away, making it even more positively charged; that doesn't sound like a good thing; that sounds like a bad thing.3137

What we can note is that this destabilizes; this destabilizes the + charge and makes conjugate acid 2... remember we are looking at conjugate acid 2... the less stable.3152

Less stable means more reactive; let's put that in there--more reactive and therefore stronger conjugate acid; because this is unstable, it is now going to be the stronger acid.3175

The stronger conjugate acid has the weaker parent base; conjugate acid 2 has the weaker parent base.3192

Who is the stronger base?--was our original question; who is more basic? 1 is the stronger base; because there is nothing to destabilize the conjugate; this looks much better.3211

Therefore this structure 1 doesn't mind getting protonated as much because it is going to a more stable conjugate.3228

Let's try another example of looking at who is the strongest base; amines are good bases.3239

Each of these nitrogens has a lone pair; and so we are asking which of them is most willing to be protonated--most likely to be protonated?--that would make it a stronger base.3249

It is possible we can look at the conjugate acids, but in this case, the answer is not going to be found in looking at those conjugate acids.3262

Because there is a different right away in looking at the stability of these three parent bases.3270

Let's take a look at resonance for example; this first amine has no stabilization; no resonance stabilization; nothing special about this structure.3278

But when we have a nitrogen attached to a benzene ring, this lone pair is now allylic or we call it benzylic when it is next to a benzene ring; and so it can have resonance.3294

That makes an N+ and a C-; and are there any other resonance forms?--there sure are.3311

This resonance form is still allylic, and we can go on and move that negative charge around the benzene ring carbon; so there is a difference right away between these two amines.3320

Let's take a look at this third structure; this amine now has a substituent, a group, attached to this carbon; let's see what effect, if any, that has on the resonance.3332

Again, because it is benzylic, we know we can draw a resonance form here--NH2+ and C-.3343

This can continue down; we have our carbonyl down here--this is an aldehyde; and this can continue down to put a negative charge at this bottom carbon.3355

When we put this lone pair at this carbon right next to the carbonyl, look what can happen--it is now allylic to that carbonyl π bond.3376

We can have a new resonance form that moves the negative charge into the carbonyl.3385

Being able to draw a new resonance form is usually a significant thing, but let's take a look at this--does this look like it's significant resonance?3399

It actually is because now we've managed to put the negative charge on an oxygen--the more electronegative oxygen; that is a better place to be than putting it on the carbon.3408

There is an additional resonance form; we can actually move the negative charge up here as well; but I think again this is enough to demonstrate a difference by having this carbonyl group attached.3418

What we can conclude now is that this third structure is the most stable because of resonance; and if it is the most stable, that means it is the least reactive; and that makes it the weakest base.3428

Right off the bat, if we can find a significant difference in the stability of our starting compounds, then that can lead right away to a difference in their basicity.3453

One way we can describe this is we could say that if we were to protonate this, if we were to protonate this nitrogen, what does that do to all this resonance?3467

It takes away that resonance, doesn't it?--because that would take away this lone pair.3479

Protonation of this compound would be a bad thing; it would be unfavorable because we would lose all this resonance stabilization.3484

What we could say is that the... just a comment we can make about this is that the lone pair is unavailable.3490

This is not a very good base because the lone pair is not around to be protonated and to react with acid; we could say that it is tied up in resonance.3500

What is another good way to describe it?--we could say that it is delocalized.3516

Remember the actual structure is a hybrid of all these different resonance forms.3520

In all these other resonance forms, there isn't even a lone pair on that nitrogen; the lone pair is spread out over all these carbon atoms and this oxygen atom as well.3526

The lone pair is unavailable, and protonation... if we were to protonate it and add an H+, protonation would lose that resonance.3537

We would cause all that resonance stabilization to disappear; that is unfavorable.3553

This kind of resonance makes this particular amine very stable and very unreactive as a base.3559

Now when we are comparing these two, we would see that again this does have some resonance so this lone pair is also tied up.3568

Compared to this amine, this has no resonance stabilization; it has no delocalization of that lone pair.3575

Because these had no stabilization, this is the most reactive strongest base.3583

What we could say here, the way we would describe this and compare this to the other ones, is we could say that the lone pair is very available.3596

This lone pair has nothing better to do than to sit around and wait for an acid to react with; so that makes him a much stronger base.3608

This is described as an alkyl amine--when we have a nitrogen on an ordinary alkyl group, just a carbon chain like this.3614

These guys are called aryl amines--when you have a nitrogen on a benzene ring.3624

We will find that this trend holds true--that aryl amines are going to be much weaker amines than akyl bases; because of this resonance effect.3634

Finally, let's take a look at some common acids and bases now that we have seen the sorts of things that can cause a compound to be a stronger acid or a stronger base.3647

Let's summarize some of the things we should know moving forward.3655

Strong acids are defined as those with negative pKa's; these are things that when in water will completely dissociate; these will completely protonate water.3660

These are ones you should already be familiar with; things like sulfuric acid, nitric acid, the halo acids--HCl, HBr, HI (we will see those a lot throughout organic chemistry), C3O+.3670

Any time you see any of these structures as part of your reaction conditions or as a reagent, you should immediately recognize them as strong acids.3684

Most often, it is going to tell you that the very first thing you are going to do in that reaction is protonate something.3693

These are fabulous proton sources, and they are very reactive, very unstable, and they are going to find a place to protonate.3699

Most definitely, if you don't already recognize these as strong acids, you can make up some flashcards so that they will be more familiar to you.3708

Weak acids are things that generally have a low pKa--somewhere below 16 or so.3716

What falls in this category is this arrangement when we have a carbonyl with an OH; these are known as carboxylic acids.3724

Carboxylic acid has a pKa somewhere around 5; it is quite easy to deprotonate a carboxylic acid.3732

Ammonium, NH,4+, is also a decent acid, quite easy to donate a proton; as is water and just an ordinary alcohol.3738

An alcohol has a pKa closer to this 16; a carboxylic acid has a pKa down here closer to 0; but all these compounds are quite resonable to deprotonate; it is quite easy to deprotonate these.3748

Things that we might describe as very weak acids are those with even higher pKa's, above 16.3762

Something like a ketone; these protons next to a carbonyl, we will find are acidic; we can remove them, but it takes quite an effort; it takes a very strong base in order to do that.3768

Amines as well; an amine is not easy to deprotonate, but it can happen; of course, a nitrogen is less likely to lose a proton than an oxygen; so that is why we have a higher pKa here.3783

If we have a triple bond, a carbon-carbon triple bond with a hydrogen on it, this functional group is known as an alkyne--having a carbon-carbon triple bond.3797

Hydrogens on alkynes are also possible to protonate; if you have a very, very strong base, you can protonate in these positions.3807

The other functional group listed we can describe as extremely weak acids, these numbers are so high--above 40, that we could pretty much say that these are not acids.3816

It is going to be so difficult to remove these protons, that for all intents and purposes, we could say that no reaction is going to happen; there is no base that is strong enough to deprotonate these.3828

Of course, there are exceptions to that, but in introductory level organic chemistry, we are never going to see any reactions like this.3836

Here we have an alkene--is what we call it when we have a carbon-carbon double bond, and a hydrogen on an alkene carbon will never deprotonate; we will never be able to remove.3844

The same goes for an ordinary alkane carbon; putting negative charges on these carbons would be so totally unstable that we are never going to see that.3856

Having a triple bond makes it OK; we will see that down the road when we study alkynes; but alkenes and alkanes will never deprotonate.3869

While typically we are not going to be memorizing our pKa table, it i i437 Id when we study alkynes. s very good to have a familiarity with these various functional groups.3877

And know whether or not it's going to be possible or maybe even easy to deprotonate any of these hydrogens.3884

One last example--let's see if we were to ask about the direction of an equilibrium.3892

Let's say we were given a pKa table, and we looked at the following equilibrium.3897

When we looked in the pKa table, it turns out we were able to find a pKa value for every one of these species.3902

We know that for the direction of the equilibrium, we know that the equilibrium lies the direction of the weaker acid-base pair; but how do we use this information to decide who the weakest is?3912

There is something very important to remember for a pKa; remember what that A stands for?--that is the measurement for an acid; pKa's are for acids; pKa tells us something about the strength of an acid.3935

In the forward reaction, which species is behaving as an acid?--the acid is the one who donates a proton; and it looks like the ammonium is acting as an acid.3951

In this reaction, water is acting as a base; it is accepting a proton; so in this reaction, the pKa of water is irrelevant because water is not donating a proton in this reaction.3964

So 9 is the pKa for the forward reaction; and how about the reverse reaction?--who is the acid, and who is the base?--let's take a look at the direction of that proton transfer.3978

H3O+ is going to H2O; so that means H3O+ is the acid in the reverse reaction; ammonia is reacting as a base in this reaction.3988

Which is the pKa number that is relevant to us?--just the H3O+ pKa because that is the acid for the reverse reaction.3997

Now we've identified... we've narrowed it down to the two competing acids; we've looked up their pKa's.4005

Of course, we learned in this lesson how to predict the relative acidities.4011

So we should actually be able to, even without a pKa table, we should be able to decide which is the stronger acid, NH4+ or H3O+.4016

You think you'd be able to do that?--that's a very good exercise; I think it has to do with the difference in electronegativities of nitrogen and oxygen.4027

Which of these two species is more stable?--I want you to think about that.4034

But we see here that pKa of -2 means that this is the stronger acid; pKa of 9 means this is the weaker acid; and so where does our equilibrium lie... our equilibrium direction?4038

It lies to the left; you could say that the reverse reaction is favored or that the reaction lies to the left.4053

This concludes our lesson on acid-base reactions.4060

We will see you soon back at Educator; thank you.4063