The use of aldehydes and ketones in the acetylacetic or malonic synthesis allows obtaining ketones or a,b -unsaturated acids.

condensation knoevenagel 1

Stage 1. Formation of the ketoester enolate

condensation knoevenagel 2

Step 2. Nucleophilic attack of the ketoester enolate on the carbonyl

condensation knoevenagel 3

Stage 3. Hydrolysis of the ester

condensation knoevenagel 4

Stage 4. Decarboxylation

condensation knoevenagel 5