Abstract
The reaction of (2S)-Z–Azy–OBzl, (2S,3S)-Z–3-MeAzy–OBzl, and their enantiomers with H2S gave the optically active cysteine and thero-3-methylcysteine derivatives via the stereospecific ring-opening reaction of aziridine, and subsequent oxidation and deblocking procedure gave the titled compounds in good yields.