Stereoselectivity in reactions of metal complexes VII. Asymmetric synthesis of amino acids by metal ion‐promoted transamination

Abstract Enantioselective synthesis of phenylalanine was performed by reacting phenylpyruvic acid with pyridoxamine followed by ketimine‐aldimine isomerization of the Schiff base formed catalyzed by an optically active copper (II)‐complex. By UV and CD measurements it was shown that the enantiomeric excess strongly depends on the reaction conditions and on the reaction time. In favorable cases it reached values up to 80%. The selectivity of the reaction is discussed on the basis of possible structures of the intermediate mixed ligand complex.