Name: Esters to β-Ketoesters: Claisen Condensation Overview
Uploaded: 2022-09-27T10:14:00-04:00
Duration: 1 min 24 s
Description: Regular Claisen condensation is a base-promoted reaction involving identical esters with two α hydrogens, condensing to produce β-ketoesters.

Chapter 15: α-Carbon Chemistry: Enols, Enolates, and Enamines Back To Chapter

15.27: Esters to β-Ketoesters: Claisen Condensation Overview

TABLE OF
CONTENTS

X

Chapter 1: Covalent Bonding and Structure

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1.1: What is Organic Chemistry?
30
1.2: Electronic Structure of Atoms
30
1.3: Electron Configurations
30
1.4: Chemical Bonds
30
1.5: Polar Covalent Bonds
30
1.6: Lewis Structures and Formal Charges
30
1.7: VSEPR Theory
30
1.8: Molecular Geometry and Dipole Moments
30
1.9: Resonance and Hybrid Structures
30
1.10: Valence Bond Theory and Hybridized Orbitals
30
1.11: MO Theory and Covalent Bonding
30
1.12: Intermolecular Forces and Physical Properties
30
1.13: Solubility
30
1.14: Introduction to Functional Groups
30
1.15: Overview of Advanced Functional Groups

Chapter 2: Thermodynamics and Chemical Kinetics

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2.1: Chemical Reactions
30
2.2: Enthalpy and Heat of Reaction
30
2.3: Energetics of Solution Formation
30
2.4: Entropy and Solvation
30
2.5: Gibbs Free Energy and Thermodynamic Favorability
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2.6: Chemical and Solubility Equilibria
30
2.7: Rate Law and Reaction Order
30
2.8: Effect of Temperature Change on Reaction Rate
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2.9: Multi-Step Reactions
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2.10: Bond Dissociation Energy and Activation Energy
30
2.11: Energy Diagrams, Transition States, and Intermediates
30
2.12: Predicting Reaction Outcomes

Chapter 3: Alkanes and Cycloalkanes

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3.1: Structure of Alkanes
30
3.2: Constitutional Isomers of Alkanes
30
3.3: Nomenclature of Alkanes
30
3.4: Physical Properties of Alkanes
30
3.5: Newman Projections
30
3.6: Conformations of Ethane and Propane
30
3.7: Conformations of Butane
30
3.8: Cycloalkanes
30
3.9: Conformations of Cycloalkanes
30
3.10: Conformations of Cyclohexane
30
3.11: Chair Conformation of Cyclohexane
30
3.12: Stability of Substituted Cyclohexanes
30
3.13: Disubstituted Cyclohexanes: cis-trans Isomerism
30
3.14: Combustion Energy: A Measure of Stability in Alkanes and Cycloalkanes

Chapter 4: Stereoisomerism

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4.1: Chirality
30
4.2: Isomerism
30
4.3: Stereoisomers
30
4.4: Naming Enantiomers
30
4.5: Properties of Enantiomers and Optical Activity
30
4.6: Molecules with Multiple Chiral Centers
30
4.7: Fischer Projections
30
4.8: Racemic Mixtures and the Resolution of Enantiomers
30
4.9: Stereoisomerism of Cyclic Compounds
30
4.10: Chirality at Nitrogen, Phosphorus, and Sulfur
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4.11: Prochirality
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4.12: Chirality in Nature

Chapter 5: Acids and Bases

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5.1: Brønsted-Lowry Acids and Bases
30
5.2: Lewis Acids and Bases
30
5.3: Acid and Bases: Ka, pKa, and Relative Strengths
30
5.4: Position of Equilibrium in Acid-Base Reactions
30
5.5: Molecular Structure and Acidity
30
5.6: Leveling Effect and Non-Aqueous Acid-Base Solutions
30
5.7: Solvating Effects

Chapter 6: Nucleophilic Substitution and Elimination Reactions of Alkyl Halides

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6.1: Alkyl Halides
30
6.2: Nucleophilic Substitution Reactions
30
6.3: Nucleophiles
30
6.4: Electrophiles
30
6.5: Leaving Groups
30
6.6: Carbocations
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6.7: SN2 Reaction: Kinetics
30
6.8: SN2 Reaction: Mechanism
30
6.9: SN2 Reaction: Transition State
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6.10: SN2 Reaction: Stereochemistry
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6.11: SN1 Reaction: Kinetics
30
6.12: SN1 Reaction: Mechanism
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6.13: SN1 Reaction: Stereochemistry
30
6.14: Predicting Products: SN1 vs. SN2
30
6.15: Elimination Reactions
30
6.16: E2 Reaction: Kinetics and Mechanism
30
6.17: E2 Reaction: Stereochemistry and Regiochemistry
30
6.18: E1 Reaction: Kinetics and Mechanism
30
6.19: E1 Reaction: Stereochemistry and Regiochemistry
30
6.20: Predicting Products: Substitution vs. Elimination

Chapter 7: Alkene Structure and Reactivity

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7.1: Structure and Bonding of Alkenes
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7.2: Nomenclature of Alkenes
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7.3: Degree of Unsaturation
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7.4: Isomerism in Alkenes
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7.5: Relative Stabilities of Alkenes
30
7.6: Introduction to Electrophilic Addition Reactions of Alkenes
30
7.7: Regioselectivity of Electrophilic Additions to Alkenes: Markovnikov's Rule

Chapter 8: Reactions of Alkenes

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8.1: Regioselectivity of Electrophilic Additions-Peroxide Effect
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8.2: Free-Radical Chain Reaction and Polymerization of Alkenes
30
8.3: Halogenation of Alkenes
30
8.4: Formation of Halohydrin from Alkenes
30
8.5: Acid-Catalyzed Hydration of Alkenes
30
8.6: Regioselectivity and Stereochemistry of Acid-Catalyzed Hydration
30
8.7: Oxymercuration-Reduction of Alkenes
30
8.8: Hydroboration-Oxidation of Alkenes
30
8.9: Regioselectivity and Stereochemistry of Hydroboration
30
8.10: Oxidation of Alkenes: Syn Dihydroxylation with Osmium Tetraoxide
30
8.11: Oxidation of Alkenes: Syn Dihydroxylation with Potassium Permanganate
30
8.12: Oxidation of Alkenes: Anti Dihydroxylation with Peroxy Acids
30
8.13: Oxidative Cleavage of Alkenes: Ozonolysis
30
8.14: Reduction of Alkenes: Catalytic Hydrogenation
30
8.15: Reduction of Alkenes: Asymmetric Catalytic Hydrogenation

Chapter 9: Alkynes

30
9.1: Structure and Physical Properties of Alkynes
30
9.2: Nomenclature of Alkynes
30
9.3: Acidity of 1-Alkynes
30
9.4: Preparation of Alkynes: Alkylation Reaction
30
9.5: Preparation of Alkynes: Dehydrohalogenation
30
9.6: Electrophilic Addition to Alkynes: Halogenation
30
9.7: Electrophilic Addition to Alkynes: Hydrohalogenation
30
9.8: Alkynes to Aldehydes and Ketones: Acid-Catalyzed Hydration
30
9.9: Alkynes to Aldehydes and Ketones: Hydroboration-Oxidation
30
9.10: Alkynes to Carboxylic Acids: Oxidative Cleavage
30
9.11: Reduction of Alkynes to cis-Alkenes: Catalytic Hydrogenation
30
9.12: Reduction of Alkynes to trans-Alkenes: Sodium in Liquid Ammonia

Chapter 10: Alcohols and Phenols

30
10.1: Structure and Nomenclature of Alcohols and Phenols
30
10.2: Physical Properties of Alcohols and Phenols
30
10.3: Acidity and Basicity of Alcohols and Phenols
30
10.4: Preparation of Alcohols via Addition Reactions
30
10.5: Preparation of Alcohols via Substitution Reactions
30
10.6: Acid-Catalyzed Dehydration of Alcohols to Alkenes
30
10.7: Alcohols from Carbonyl Compounds: Reduction
30
10.8: Alcohols from Carbonyl Compounds: Grignard Reaction
30
10.9: Protection of Alcohols
30
10.10: Preparation of Diols and Pinacol Rearrangement
30
10.11: Conversion of Alcohols to Alkyl Halides
30
10.12: Oxidation of Alcohols

Chapter 11: Ethers, Epoxides, Sulfides

30
11.1: Structure and Nomenclature of Ethers
30
11.2: Physical Properties of Ethers
30
11.3: Ethers from Alcohols: Alcohol Dehydration and Williamson Ether Synthesis
30
11.4: Ethers from Alkenes: Alcohol Addition and Alkoxymercuration-Demercuration
30
11.5: Ethers to Alkyl Halides: Acidic Cleavage
30
11.6: Autoxidation of Ethers to Peroxides and Hydroperoxides
30
11.7: Crown Ethers
30
11.8: Structure and Nomenclature of Epoxides
30
11.9: Preparation of Epoxides
30
11.10: Sharpless Epoxidation
30
11.11: Acid-Catalyzed Ring-Opening of Epoxides
30
11.12: Base-Catalyzed Ring-Opening of Epoxides
30
11.13: Structure and Nomenclature of Thiols and Sulfides
30
11.14: Preparation and Reactions of Thiols
30
11.15: Preparation and Reactions of Sulfides

Chapter 12: Aldehydes and Ketones

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12.1: Structures of Aldehydes and Ketones
30
12.3: IUPAC Nomenclature of Aldehydes
30
12.4: IUPAC Nomenclature of Ketones
30
12.5: Common Names of Aldehydes and Ketones
30
12.6: IR and UV–Vis Spectroscopy of Aldehydes and Ketones
30
12.7: NMR Spectroscopy and Mass Spectrometry of Aldehydes and Ketones
30
12.8: Preparation of Aldehydes and Ketones from Alcohols, Alkenes, and Alkynes
30
12.9: Preparation of Aldehydes and Ketones from Nitriles and Carboxylic Acids
30
12.10: Preparation of Aldehydes and Ketones from Carboxylic Acid Derivatives
30
12.13: Nucleophilic Addition to the Carbonyl Group: General Mechanism
30
12.14: Aldehydes and Ketones with Water: Hydrate Formation
30
12.15: Aldehydes and Ketones with Alcohols: Hemiacetal Formation
30
12.18: Protecting Groups for Aldehydes and Ketones: Introduction
30
12.19: Acetals and Thioacetals as Protecting Groups for Aldehydes and Ketones
30
12.20: Aldehydes and Ketones with HCN: Cyanohydrin Formation Overview
30
12.21: Aldehydes and Ketones with HCN: Cyanohydrin Formation Mechanism
30
12.22: Aldehydes and Ketones to Alkenes: Wittig Reaction Overview
30
12.23: Aldehydes and Ketones to Alkenes: Wittig Reaction Mechanism
30
12.24: Aldehydes and Ketones with Amines: Imine and Enamine Formation Overview
30
12.25: Aldehydes and Ketones with Amines: Imine Formation Mechanism
30
12.26: Aldehydes and Ketones with Amines: Enamine Formation Mechanism
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12.29: Aldehydes and Ketones to Alkanes: Wolff–Kishner Reduction
30
12.30: Oxidations of Aldehydes and Ketones to Carboxylic Acids
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12.31: Reactions of Aldehydes and Ketones: Baeyer–Villiger Oxidation
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12.33: Keto–Enol Tautomerism: Mechanism

Chapter 13: Carboxylic Acids

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13.1: IUPAC Nomenclature of Carboxylic Acids
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13.4: Physical Properties of Carboxylic Acids
30
13.5: Acidity of Carboxylic Acids
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13.6: Substituent Effects on Acidity of Carboxylic Acids
30
13.7: IR and UV–Vis Spectroscopy of Carboxylic Acids
30
13.8: NMR and Mass Spectroscopy of Carboxylic Acids
30
13.9: Preparation of Carboxylic Acids: Overview
30
13.10: Preparation of Carboxylic Acids: Hydrolysis of Nitriles
30
13.11: Preparation of Carboxylic Acids: Carboxylation of Grignard Reagents
30
13.12: Reactions of Carboxylic Acids: Introduction
30
13.13: Carboxylic Acids to Esters: Acid-Catalyzed (Fischer) Esterification Overview
30
13.14: Carboxylic Acids to Esters: Acid-Catalyzed (Fischer) Esterification Mechanism
30
13.15: Carboxylic Acids to Methylesters: Alkylation using Diazomethane
30
13.16: Carboxylic Acids to Acid Chlorides
30
13.17: Carboxylic Acids to Primary Alcohols: Hydride Reduction
30
13.18: Loss of Carboxy Group as CO2: Decarboxylation of β-Ketoacids
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13.19: Loss of Carboxy Group as CO2: Decarboxylation of Malonic Acid Derivatives

Chapter 14: Carboxylic Acid Derivatives

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14.1: Carboxylic Acid Derivatives: Overview
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14.2: Nomenclature of Carboxylic Acid Derivatives: Acid Halides, Esters, and Acid Anhydrides
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14.3: Nomenclature of Carboxylic Acid Derivatives: Amides and Nitriles
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14.4: Structures of Carboxylic Acid Derivatives
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14.5: Physical Properties of Carboxylic Acid Derivatives
30
14.6: Acidity and Basicity of Carboxylic Acid Derivatives
30
14.7: Spectroscopy of Carboxylic Acid Derivatives
30
14.8: Relative Reactivity of Carboxylic Acid Derivatives
30
14.9: Nucleophilic Acyl Substitution of Carboxylic Acid Derivatives
30
14.10: Acid Halides to Carboxylic Acids: Hydrolysis
30
14.11: Acid Halides to Esters: Alcoholysis
30
14.12: Acid Halides to Amides: Aminolysis
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14.13: Acid Halides to Alcohols: LiAlH4 Reduction
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14.14: Acid Halides to Alcohols: Grignard Reaction
30
14.15: Acid Halides to Ketones: Gilman Reagent
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14.16: Preparation of Acid Anhydrides
30
14.17: Reactions of Acid Anhydrides
30
14.18: Esters to Carboxylic Acids: Saponification
30
14.19: Esters to Carboxylic Acids: Acid-Catalyzed Hydrolysis
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14.20: Esters to Alcohols: Hydride Reductions
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14.21: Esters to Alcohols: Grignard Reaction
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14.22: Preparation of Amides
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14.23: Amides to Carboxylic Acids: Hydrolysis
30
14.24: Amides to Amines: LiAlH4 Reduction
30
14.25: Preparation of Nitriles
30
14.26: Nitriles to Carboxylic Acids: Hydrolysis
30
14.27: Nitriles to Ketones: Grignard Reaction
30
14.28: Nitriles to Amines: LiAlH4 Reduction

Chapter 15: α-Carbon Chemistry: Enols, Enolates, and Enamines

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15.1: Reactivity of Enols
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15.2: Reactivity of Enolate Ions
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15.3: Types of Enols and Enolates
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15.4: Enolate Mechanism Conventions
30
15.5: Regioselective Formation of Enolates
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15.6: Stereochemical Effects of Enolization
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15.7: Acid-Catalyzed α-Halogenation of Aldehydes and Ketones
30
15.8: Base-Promoted α-Halogenation of Aldehydes and Ketones
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15.9: Multiple Halogenation of Methyl Ketones: Haloform Reaction
30
15.10: α-Halogenation of Carboxylic Acid Derivatives: Overview
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15.11: α-Bromination of Carboxylic Acids: Hell–Volhard–Zelinski Reaction
30
15.12: Reactions of α-Halocarbonyl Compounds: Nucleophilic Substitution
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15.13: Nitrosation of Enols
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15.14: C–C Bond Formation: Aldol Condensation Overview
30
15.15: Base-Catalyzed Aldol Addition Reaction
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15.16: Acid-Catalyzed Aldol Addition Reaction
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15.17: Dehydration of Aldols to Enals: Base-Catalyzed Aldol Condensation
30
15.18: Dehydration of Aldols to Enones: Acid-Catalyzed Aldol Condensation
30
15.19: Intramolecular Aldol Reaction
30
15.20: C–C Bond Cleavage: Retro-Aldol Reaction
30
15.21: Crossed Aldol Reactions: Overview
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15.22: Crossed Aldol Reaction Using Weak Bases
30
15.23: Ketones with Nonenolizable Aromatic Aldehydes: Claisen–Schmidt Condensation
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15.24: Crossed Aldol Reaction Using Strong Bases: Directed Aldol Reaction
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15.26: Aldol Condensation with β-Diesters: Knoevenagel Condensation
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15.27: Esters to β-Ketoesters: Claisen Condensation Overview
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15.28: Esters to β-Ketoesters: Claisen Condensation Mechanism
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15.29: Aldol Condensation vs Claisen Condensation
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15.30: Intramolecular Claisen Condensation of Dicarboxylic Esters: Dieckmann Cyclization
30
15.31: β-Dicarbonyl Compounds via Crossed Claisen Condensations
30
15.32: α-Alkylation of Ketones via Enolate Ions
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15.33: Factors Affecting α-Alkylation of Ketones: Choice of Base
30
15.34: Alkylation of β-Ketoester Enolates: Acetoacetic Ester Synthesis
30
15.35: Alkylation of β-Diester Enolates: Malonic Ester Synthesis
30
15.36: Conjugate Addition to α,β-Unsaturated Carbonyl Compounds
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15.37: Conjugate Addition (1,4-Addition) vs Direct Addition (1,2-Addition)
30
15.38: Conjugate Addition of Enolates: Michael Addition
30
15.39: Cyclohexenones via Michael Addition and Aldol Condensation: The Robinson Annulation
30
15.40: Synthesis of α-Substituted Carbonyl Compounds: The Stork Enamine Reaction
30
15.42: Nonenolizable Aldehydes to Acids and Alcohols: The Cannizzaro Reaction

Chapter 16: Dienes, Conjugated Pi Systems, and Pericyclic Reactions

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16.1: Structure of Conjugated Dienes
30
16.2: Stability of Conjugated Dienes
30
16.3: π Molecular Orbitals of 1,3-Butadiene
30
16.4: π Molecular Orbitals of the Allyl Cation and Anion
30
16.5: π Molecular Orbitals of the Allyl Radical
30
16.6: Electrophilic 1,2- and 1,4-Addition of HX to 1,3-Butadiene
30
16.7: Electrophilic 1,2- and 1,4-Addition of X2 to 1,3-Butadiene
30
16.8: Electrophilic Addition of HX to 1,3-Butadiene: Thermodynamic vs Kinetic Control
30
16.9: UV–Vis Spectroscopy of Conjugated Systems
30
16.10: UV–Vis Spectroscopy: Woodward–Fieser Rules
30
16.11: Pericyclic Reactions: Introduction
30
16.12: Thermal and Photochemical Electrocyclic Reactions: Overview
30
16.13: Thermal Electrocyclic Reactions: Stereochemistry
30
16.14: Photochemical Electrocyclic Reactions: Stereochemistry
30
16.15: Cycloaddition Reactions: Overview
30
16.16: Cycloaddition Reactions: MO Requirements for Thermal Activation
30
16.17: Cycloaddition Reactions: MO Requirements for Photochemical Activation
30
16.18: [4+2] Cycloaddition of Conjugated Dienes: Diels–Alder Reaction
30
16.19: Diels–Alder vs Retro-Diels–Alder Reaction: Thermodynamic Factors
30
16.20: Diels–Alder Reaction Forming Cyclic Products: Stereochemistry
30
16.21: Diels–Alder Reaction Forming Bridged Bicyclic Products: Stereochemistry
30
16.22: Diels–Alder Reaction: Characteristics of Dienes
30
16.23: Diels–Alder Reaction: Characteristics of Dienophiles
30
16.24: Thermal Sigmatropic Reactions: Overview
30
16.25: [3,3] Sigmatropic Rearrangement of 1,5-Dienes: Cope Rearrangement
30
16.26: [3,3] Sigmatropic Rearrangement of Allyl Vinyl Ethers: Claisen Rearrangement
30
16.27: Woodward–Hoffmann Selection Rules and Microscopic Reversibility

Chapter 17: Aromatic Compounds

30
17.1: Aromatic Compounds: Overview
30
17.2: Nomenclature of Aromatic Compounds with a Single Substituent
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17.3: Nomenclature of Aromatic Compounds with Multiple Substituents
30
17.4: Structure of Benzene: Kekulé Model
30
17.5: Structure of Benzene: Molecular Orbital Model
30
17.7: Criteria for Aromaticity and the Hückel 4n + 2 Rule
30
17.8: Hückel's Rule Diagram of π MOs: Frost Circle
30
17.9: Frost Circles for Different Conjugated Systems
30
17.13: Aromatic Hydrocarbon Anions: Structural Overview
30
17.14: Aromatic Hydrocarbon Cations: Structural Overview
30
17.15: Five-Membered Heterocyclic Aromatic Compounds: Overview
30
17.19: NMR Spectroscopy of Aromatic Compounds

Chapter 18: Reactions of Aromatic Compounds

30
18.4: NMR Spectroscopy of Benzene Derivatives
30
18.5: Reactions at the Benzylic Position: Oxidation and Reduction
30
18.7: Reactions at the Benzylic Position: Halogenation
30
18.8: Electrophilic Aromatic Substitution: Overview
30
18.9: Electrophilic Aromatic Substitution: Chlorination and Bromination of Benzene
30
18.10: Electrophilic Aromatic Substitution: Fluorination and Iodination of Benzene
30
18.11: Electrophilic Aromatic Substitution: Nitration of Benzene
30
18.12: Electrophilic Aromatic Substitution: Sulfonation of Benzene
30
18.13: Electrophilic Aromatic Substitution: Friedel–Crafts Alkylation of Benzene
30
18.14: Electrophilic Aromatic Substitution: Friedel–Crafts Acylation of Benzene
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18.15: Limitations of Friedel–Crafts Reactions
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18.16: Directing Effect of Substituents: ortho–para-Directing Groups
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18.17: Directing Effect of Substituents: meta-Directing Groups
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18.18: ortho–para-Directing Activators: –CH3, –OH, –⁠NH2, –OCH3
30
18.19: ortho–para-Directing Deactivators: Halogens
30
18.20: meta-Directing Deactivators: –NO2, –CN, –CHO, –⁠CO2R, –COR, –CO2H
30
18.21: Directing and Steric Effects in Disubstituted Benzene Derivatives
30
18.23: Nucleophilic Aromatic Substitution: Addition–Elimination (SNAr)
30
18.24: Nucleophilic Aromatic Substitution: Elimination–Addition
30
18.25: Nucleophilic Aromatic Substitution of Aryldiazonium Salts: Aromatic SN1
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18.26: Reduction of Benzene to Cyclohexane: Catalytic Hydrogenation
30
18.28: Benzene to 1,4-Cyclohexadiene: Birch Reduction Mechanism
30
18.29: Hydrolysis of Chlorobenzene to Phenol: Dow Process
30
18.30: Benzene to Phenol via Cumene: Hock Process
30
18.32: Oxidation of Phenols to Quinones

Chapter 19: Amines

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19.1: Amines: Introduction
30
19.2: Nomenclature of Primary Amines
30
19.3: Nomenclature of Secondary and Tertiary Amines
30
19.4: Nomenclature of Aryl and Heterocyclic Amines
30
19.5: Structure of Amines
30
19.6: Physical Properties of Amines
30
19.7: Basicity of Aliphatic Amines
30
19.8: Basicity of Aromatic Amines
30
19.9: Basicity of Heterocyclic Aromatic Amines
30
19.10: NMR Spectroscopy Of Amines
30
19.12: Mass Spectrometry of Amines
30
19.13: Preparation of Amines: Alkylation of Ammonia and Amines
30
19.14: Preparation of 1° Amines: Azide Synthesis
30
19.15: Preparation of 1° Amines: Gabriel Synthesis
30
19.16: Preparation of Amines: Reduction of Oximes and Nitro Compounds
30
19.17: Preparation of Amines: Reduction of Amides and Nitriles
30
19.18: Preparation of Amines: Reductive Amination of Aldehydes and Ketones
30
19.19: Preparation of 1° Amines: Hofmann and Curtius Rearrangement Overview
30
19.20: Preparation of 1° Amines: Hofmann and Curtius Rearrangement Mechanism
30
19.21: Amines to Amides: Acylation of Amines
30
19.22: Amines to Alkenes: Hofmann Elimination
30
19.24: Amines to Alkenes: Cope Elimination
30
19.25: 1° Amines to Diazonium or Aryldiazonium Salts: Diazotization with NaNO2 Overview
30
19.26: 1° Amines to Diazonium or Aryldiazonium Salts: Diazotization with NaNO2 Mechanism
30
19.27: 2° Amines to N-Nitrosamines: Reaction with NaNO2
30
19.28: Diazonium Group Substitution with Halogens and Cyanide: Sandmeyer and Schiemann Reactions
30
19.29: Diazonium Group Substitution: –OH and –H
30
19.30: Aryldiazonium Salts to Azo Dyes: Diazo Coupling
30
19.31: Amines to Sulfonamides: The Hinsberg Test

Chapter 20: Radical Chemistry

30
20.1: Radicals: Electronic Structure and Geometry
30
20.4: Electron Paramagnetic Resonance (EPR) Spectroscopy: Organic Radicals
30
20.5: Radical Formation: Overview
30
20.6: Radical Formation: Homolysis
30
20.7: Radical Formation: Abstraction
30
20.8: Radical Formation: Addition
30
20.9: Radical Formation: Elimination
30
20.10: Radical Reactivity: Overview
30
20.11: Radical Reactivity: Steric Effects
30
20.12: Radical Reactivity: Concentration Effects
30
20.13: Radical Reactivity: Electrophilic Radicals
30
20.14: Radical Reactivity: Nucleophilic Radicals
30
20.15: Radical Reactivity: Intramolecular vs Intermolecular
30
20.16: Radical Autoxidation
30
20.17: Radical Oxidation of Allylic and Benzylic Alcohols
30
20.18: Radical Substitution: Halogenation of Alkanes and Alkyl Substituents
30
20.19: Radical Halogenation: Thermodynamics
30
20.21: Radical Halogenation: Stereochemistry
30
20.22: Radical Substitution: Allylic Chlorination
30
20.23: Radical Substitution: Allylic Bromination
30
20.24: Radical Substitution: Hydrogenolysis of Alkyl Halides with Tributyltin Hydride
30
20.25: Radical Anti-Markovnikov Addition to Alkenes: Overview
30
20.26: Radical Anti-Markovnikov Addition to Alkenes: Mechanism
30
20.27: Radical Anti-Markovnikov Addition to Alkenes: Thermodynamics
30
20.28: Vicinal Diols via Reductive Coupling of Aldehydes or Ketones: Pinacol Coupling Overview
30
20.30: Alkenes via Reductive Coupling of Aldehydes or Ketones: McMurry Reaction
30
20.31: α-Hydroxy Ketones via Reductive Coupling of Esters: Acyloin Condensation Overview

Chapter 21: Synthetic Polymers

30
21.2: Characteristics and Nomenclature of Homopolymers
30
21.3: Characteristics and Nomenclature of Copolymers
30
21.4: Polymers: Defining Molecular Weight
30
21.5: Polymers: Molecular Weight Distribution
30
21.6: Polymer Classification: Architecture
30
21.7: Polymer Classification: Crystallinity
30
21.8: Polymer Classification: Stereospecificity
30
21.10: Radical Chain-Growth Polymerization: Overview
30
21.11: Radical Chain-Growth Polymerization: Mechanism
30
21.12: Radical Chain-Growth Polymerization: Chain Branching
30
21.13: Anionic Chain-Growth Polymerization: Overview
30
21.14: Anionic Chain-Growth Polymerization: Mechanism
30
21.16: Cationic Chain-Growth Polymerization: Mechanism
30
21.17: Ziegler–Natta Chain-Growth Polymerization: Overview
30
21.19: Step-Growth Polymerization: Overview
30
21.20: Molecular Weight of Step-Growth Polymers
30
21.22: Types of Step-Growth Polymers: Polyesters
30
21.24: Olefin Metathesis Polymerization: Overview
30
21.25: Olefin Metathesis Polymerization: Ring-Opening Metathesis Polymerization (ROMP)
30
21.26: Olefin Metathesis Polymerization: Acyclic Diene Metathesis (ADMET)

Full Table of Contents

JoVE Core
Organic Chemistry

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Esters to β-Ketoesters: Claisen Condensation Overview

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15.26: Aldol Condensation with β-Diesters: Knoevenagel Condensation

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15.28: Esters to β-Ketoesters: Claisen Condensation Mechanism

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TRANSCRIPT

Regular Claisen condensation is the reaction when identical ester molecules bearing two α hydrogens combine to generate a β-keto ester—a molecule comprising a keto group β to the ester group.

Claisen condensations require nonaqueous alkoxide bases to initiate the reaction by deprotonating the α hydrogen of the ester and producing the nucleophilic enolate.

The base employed is specific and must be identical to the alkoxy group of the starting ester molecule.

For instance, Claisen condensation of an ethyl ester—promoted by an ethoxide base—produces the desired β-keto ester in decent yields.

If, instead, a methoxide base is used, nucleophilic addition at the carbonyl carbon of the ester takes place, rather than deprotonation of the α hydrogen, to give a transesterification product.

Also, the use of hydroxide bases is forbidden, as it results in irreversible hydrolysis of esters to carboxylate ions.

In summary, Claisen condensation is a nucleophilic acyl substitution reaction wherein a nucleophilic ester enolate reacts with another ester molecule to produce a β-ketoester.

15.27: Esters to β-Ketoesters: Claisen Condensation Overview

Regular Claisen condensation is a base-promoted reaction involving identical esters with two α hydrogens, condensing to produce β-ketoesters. It is a nucleophilic acyl substitution reaction wherein one of the ester molecules, upon deprotonation by the base, forms a nucleophilic enolate ion, while the other molecule serves as an electrophile.

The condensation reaction requires specific nonaqueous bases, such as alkoxide, which must be similar to the alkoxy group of the ester molecule. The use of different alkoxide ions often leads to the transesterification product. Also, the use of hydroxide bases is avoided as they result in irreversible hydrolysis of the esters to carboxylate ions.

Chapter 1: Covalent Bonding and Structure

Chapter 2: Thermodynamics and Chemical Kinetics

Chapter 3: Alkanes and Cycloalkanes

Chapter 4: Stereoisomerism

Chapter 5: Acids and Bases

Chapter 6: Nucleophilic Substitution and Elimination Reactions of Alkyl Halides

Chapter 7: Alkene Structure and Reactivity

Chapter 8: Reactions of Alkenes

Chapter 9: Alkynes

Chapter 10: Alcohols and Phenols

Chapter 11: Ethers, Epoxides, Sulfides

Chapter 12: Aldehydes and Ketones

Chapter 13: Carboxylic Acids

Chapter 14: Carboxylic Acid Derivatives

Chapter 15: α-Carbon Chemistry: Enols, Enolates, and Enamines

Chapter 16: Dienes, Conjugated Pi Systems, and Pericyclic Reactions

Chapter 17: Aromatic Compounds

Chapter 18: Reactions of Aromatic Compounds

Chapter 19: Amines

Chapter 20: Radical Chemistry

Chapter 21: Synthetic Polymers

15.27: Esters to β-Ketoesters: Claisen Condensation Overview

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