Chapter 22. The Chemistry of Enolate Ions, Enols, and α,β-Unsaturated Carbonyl

Compounds

Acidity of carbonyl compounds

An orbital interaction of acetaldehyde

Acid- or base-catalyzed enolization

Base-catalyzed

Acid-catalyzed

Racemization through enolization Acid-catalyzed

Base-catalyzed

For comparison: Br2 addition to alkenes

Haloform Reactions

Prepare α,β-unsaturated carbonyl compounds using aldol condensation

Claisen Condensation

Rainer Ludwig Claisen

Dieckmann condensation: intramolecular Claisen condensation

Walter Dieckmann

University of Munich

Crossed Claisen condensation

Conjugate addition reactions with ester and nitrile

Acid-catalyzed conjugate addition reactions

1,2- vs 1,4-additionWith 1,3-butadiene

With α,β-unsaturated carbonyl compounds

Comparison between conjugate addition and carbonyl addition

Thermodynamic control vs. kinetic control products

Robinson Annulation

Reduction with LAH is kinetically controlled