Optical Resolution of a DL-Amino-acid by a Stereoselective Ligand Exchange Reaction

Abstract

FEW investigations of the utilization of metal chelate compounds for the optical resolution of racemic compounds have so far been reported^1–4. DL-Aspartic acid copper complex was optically resolved completely from its supersaturated solution by seeding it with D- or L-aspartic acid copper complexes¹. Bailar et al. first reported the stereo-specific (stereoselective) ligand exchange reaction², and later they reported the partial optical resolution of DL-alanine by use of the reaction of DL-alanine with copper glutamate (optical purity 3.3 per cent³). Recently, Shibata et al.⁴ reported the partial optical resolution of DL-alanine in 25.6 per cent optical purity by use of the aspartic acid cobalt(III) complex.