Chapter 21, Problem 21.72P

Interpretation Introduction

Interpretation:

The Gabriel–malonic ester synthesis is used to make α-amino acids shown. The complete, detailed mechanisms for the given set of reactions and the structure of the intermediate A is to be drawn.

Concept introduction:

The Gabriel–malonic ester synthesis utilizes Gabriel Amine Synthesis and Malonic Ester Synthesis. In the mechanism, four acid catalyzed hydrolysis reactions take place (two on the imide $\text{C=O}$ groups and one on each of the two ester $\text{C=O}$ groups, forming the four carboxylic ($\text{RCO}\text{H}$) groups and freeing up the amino (${\text{NH}}_{\text{2}}$) group. The dicarboxylic acid that is formed is a $\text{β-}$ diacid and, therefore, undergoes decarboxylation with heat.