Enantioselective amino acid synthesis by chiral phase-transfer catalysis

Enantioselective synthesis of α-amino acids was greatly advanced by the creation of new chiral phase-transfer catalysts, which maximize the characteristic features of the central quaternary ammonium cations. Indeed, such phase-transfer-catalyzed enatioselective syntheses of α-amino acids were very useful in practical synthesis, and their applications were illustrated in numerous papers. This paper describes the enantioselective reactions which clearly demonstrate the high ability and great potential of chiral phase-transfer catalysis to synthesize various types of chiral α-amino acid derivatives.