ENANTIOSELECTIVE SYNTHESIS OF ALPHA-AMINO-ACIDS FROM GLYCINE T-BUTYL ESTER

Enantioselective syntheses of optically active a-amino acids from glyc ine I-butyl ester through Schiff base employing (+)-N-alkyl-10-camphor sulfonamides as chiral auxiliaries were described. Methylation of Schi ff base 5 gave high asymmetric inductions, whereas ethylation, allylat ion and benzylation gave fair asymmetric inductions. The stereochemist ry of the major alkylation product was S configuration at the newly fo rmed stereogenic center with the exception of the benzylation reaction in which the X configuration was generated. (C) 1997 Elsevier Science Ltd.