Investigation of the synthetic and mechanistic aspects of the highly stereoselective transformation of α-thioamides to α-thio-β-chloroacrylamides

Abstract

Treatment of a series of α-thioamides with N-chlorosuccinimide results in efficient transformation to the analogous α-thio-β-chloroacrylamides. The mechanistic pathway has been established through isolation and characterisation of intermediate compounds. The scope of the transformation has been explored—aryl and alkylthio substituents, primary, secondary and tertiary amides can be employed. In most instances, the chloroacrylamides are formed exclusively as the Z-stereoisomer; however, with tertiary propanamides or with amides derived from butanoic or pentanoic acid a mixture of E- and Z-stereoisomers is formed.