Synthesis of L‐glutamic acid stereospecifically labeled at C‐4 with deuterium

Abstract
4‐[2H2]‐L‐glutamic acid was prepared in excellent yield by enzymatic reductive amination of 4‐[2H2]‐2‐ketoglutaric acid. The synthesis of stereospecifically deuterated (4 R) and (4 S)‐[4‐2H2]‐L‐glutamic acids from (2 RS, 4 S) and (2 RS, 4 R)‐4‐hydroxyglutamic acids, involving a reduction step by sodium cyanoborodeuteride, was shown to proceed with 75% inversion of configuration.