Malonic ester synthesis

The malonic ester synthesis is a chemical reaction where diethyl malonate or another ester of malonic acid is alkylated at the carbon alpha (directly adjacent) to both carbonyl groups, and then converted to a substituted acetic acid.

Mechanism
A strong base is required to deprotonate the center proton. The protons alpha to carbonyl groups are easily deprotonated. The malonic ester is especially so by virtue of being adjacent to two carbonyl groups. The carbanion formed can undergo nucleophilic substitution on the alkyl halide, to give the alkylated compound. On heating, the di-ester undergoes thermal decarboxylation, yielding an acetic acid substituted by the appropriate R group.