The Malonic Ester Synthesis
Suggest a synthesis for the molecule shown on the left, beginning with diethyl malonate and any other required starting materials.Click the mouse on the compound to view the answer;
click on the button to view those fragments of the molecule which originate from diethyl malonate and the bonds which were made to the alkyl halide.
Diethyl malonate forms an enolate anion which attacks the alkyl halide to give the monoalkyl ester. Treatment with aqueous acid cleaves both ester groups, leaving a b-diacid. This undergoes rapid decarboxylation to give an intermediate enol, which rearranges to give the final product.
The portion of the molecule which originated as diethyl malonate is shown in blue. The bond which was formed to the alkyl halide is shown with the red line. The structure of the alkyl halide can be determined by simply breaking this bond and replacing the malonate fragment with a halogen. Remember that malonate will donate a carboxyl group and the alpha carbon to the final product.