Synthesis of 7-azabicyclo[2.2.1]heptane-1,4-dicarboxylic acid, a rigid non-chiral analogue of 2-aminoadipic acid

A non-chiral, rigid 7-azabicyclo[2.2.1]heptane-1,4-dicarboxylic acid, an analogue of 2-aminoadipic acid, has been synthesized in six steps from dimethyl-meso-2,5-dibromohexanedioate in 28% total yield. A key step in the synthesis is double alkylation of a dimethyl pyrrolidine-2,5-dicarboxylate by 1-bromo-2-chloroethane.