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Ch. 21 - Enolate Chemistry: Reactions at the Alpha-Carbon WorksheetSee all chapters
All Chapters
Ch. 1 - A Review of General Chemistry
Ch. 2 - Molecular Representations
Ch. 3 - Acids and Bases
Ch. 4 - Alkanes and Cycloalkanes
Ch. 5 - Chirality
Ch. 6 - Thermodynamics and Kinetics
Ch. 7 - Substitution Reactions
Ch. 8 - Elimination Reactions
Ch. 9 - Alkenes and Alkynes
Ch. 10 - Addition Reactions
Ch. 11 - Radical Reactions
Ch. 12 - Alcohols, Ethers, Epoxides and Thiols
Ch. 13 - Alcohols and Carbonyl Compounds
Ch. 14 - Synthetic Techniques
Ch. 15 - Analytical Techniques: IR, NMR, Mass Spect
Ch. 16 - Conjugated Systems
Ch. 17 - Aromaticity
Ch. 18 - Reactions of Aromatics: EAS and Beyond
Ch. 19 - Aldehydes and Ketones: Nucleophilic Addition
Ch. 20 - Carboxylic Acid Derivatives: NAS
Ch. 21 - Enolate Chemistry: Reactions at the Alpha-Carbon
Ch. 22 - Condensation Chemistry
Ch. 23 - Amines
Ch. 24 - Carbohydrates
Ch. 25 - Phenols
Ch. 26 - Amino Acids, Peptides, and Proteins
Ch. 26 - Transition Metals
Tautomers of Dicarbonyl Compounds
Acid-Catalyzed Alpha-Halogentation
Base-Catalyzed Alpha-Halogentation
Haloform Reaction
Hell-Volhard-Zelinski Reaction
Overview of Alpha-Alkylations and Acylations
Enolate Alkylation and Acylation
Enamine Alkylation and Acylation
Beta-Dicarbonyl Synthesis Pathway
Acetoacetic Ester Synthesis
Malonic Ester Synthesis
Johnny Betancourt

Enolates are anions at the the alpha position of carbonyl compounds like ketones and aldehydes. They can participate in many kinds of reactions including tautomerization, alkylation, acylation, condensation, etc. 

Enolate Formation

Enolate formation oxyanion and carbanion resonance structure contributorsEnolate formation, oxyanion and carbanion resonance structure contributorsEnolate anions are intermediates of base-catalyzed tautomerization (aka tautomerism). Carbonyls and enols (aka alkene-ols) are tautomers and exist in equilibrium 

Tautomerization-mechanismTautomerization mechanismReactions:

Alkylation and Acylation

Enolate alkylation and acylationEnolate alkylation and acylation Enolates can undergo alkylation and acylation reactions. In these, the carbanion acts as a nucleophile to attack an electrophile like an alkyl halide or acyl chloride. Acylation reactions form beta-dicarbonyls

Condensation Reactions

Enolates can also attack carbonyls directly through nucleophilic addition, and in this process larger molecules are formed. Condensation reactions like Aldol, Claisen, and Dieckmann

Claisen condensation mechanismClaisen condensation mechanism

Johnny Betancourt

Johnny got his start tutoring Organic in 2006 when he was a Teaching Assistant. He graduated in Chemistry from FIU and finished up his UF Doctor of Pharmacy last year. He now enjoys helping thousands of students crush mechanisms, while moonlighting as a clinical pharmacist on weekends.