Ester Enolates and the Claisen Condensation | Organic Chemistry 3

Ester enolates and Claisen condensation are studied in this chapter: acidity and formation of β-dicarbonyl compounds, nucleophilicity of β-dicarbonyl anions, 3-ketoacids decarboxylation, malonic ester synthesis, Michael addition

Acidity of the β-Dicarbonyls

The acidity of β-dicarbonyl is due to the resonance stabilization of the corresponding anion

Formation of β-Dicarbonyl compounds

Claisen Condensation:


  1. Ester enolate formation:

  2. Nucleophilic addition:

  3. Elimination followed by deprotonation:

  4. Protonation upon acidic aqueous work-up:


The Claisen condensation is an equilibrium: a retro-Claisen condensation can be observed resulting in 2 ester molecules via a mechanism which is exactly the reverse of the forward reaction

Other Methods to form β-Dicarbonyl Compounds

Dieckmann Condensation: Intramolecular Claisen Condensation

Mixed Claisen reaction: Ester + Ketone

Nucleophilicity of β-Dicarbonyl Anions


  1. Enolate formation by deprotonation
  2. Enolate alkylation via a SN2

3-Ketoacids Decarboxylation


  1. Hydrolysis:

  2. Decarboxylation:

Malonic Ester Synthesis


  1. Enolate formation
  2. Enolate alkylation
  3. Hydrolysis
  4. Decarboxylation

Michael Addition

Mechanism: 1,4-addition