PROCESS FOR PRODUCING OPTICALLY ACTIVE ALPHA-SUBSTITUTED CYSTEINE OR SALT THEREOF, INTERMEDIATE THEREFOR, AND PROCESS FOR PRODUCING THE SAME

摘要

The present invention provides a simple, practical, and industrially advantageous process for producing an optically active alpha -substituted cysteine or a salt thereof from inexpensive and readily available materials. The present invention provides a process for producing an optically active alpha -substituted cysteine or a salt thereof by converting a cysteine derivative into a thiazoline compound and subjecting the resulting thiazoline compound to a stereoselective substituent-introducing reaction catalyzed by an optically active quaternary ammonium salt, in particular, an axially asymmetric quaternary ammonium salt to produce an optically active thiazoline compound and then hydrolyzing the resulting thiazoline compound.