Cyclization of N-Arylacrylamides via Radical Arylsulfenylation of Carbon-Carbon Double Bonds with Sulfonyl Hydrazides.

ABSTRACT

An unprecedented tandem radical sulfenylation/cyclization reaction of N-arylacrylamides with sulfonyl hydrazides has been developed in the presence of iodine for the selective synthesis of 3-(sulfenylmethyl)oxindoles and 3-sulfenyl-3,4-dihydroquinolin-2(1H)-ones. Preliminary mechanistic studies showed that sulfonyl hydrazides decomposed completely at an early stage to thiosulfonates and disulfides, both of which underwent tandem radical sulfenylation/cyclization with N-arylacrylamides at a late stage.