Iodo-sulphonylation of 1,6-enynones: a metal-free strategy to synthesize N -substituted succinimides.

An iodine-mediated radical cyclization of 1,6-enynones with sulphonyl hydrazides using tert -butyl hydroperoxide (TBHP) as the oxidant has been developed for the synthesis of iodo-sulphonylated-succinimide derivatives. The notable advantages of the developed method are metal-free conditions, broad functional group tolerance, column chromatography-free purification, high stereoselectivity ( E isomer), shorter reaction times, and the cascade construction of three new bonds (C-S, C-I, and C-C). The synthetic application of the iodo-functionality has been extended to the Heck coupling reaction with acrylonitrile and to the Suzuki coupling reaction with benzene boronic acid.