N-Iodosuccinimide as bifunctional reagent in (E)-selective C(sp2)−H sulfonylation of styrenes

Herein we report the use of N-iodosuccinimide (NIS) as a bifunctional reagent for a regio- and (E)-selective C(sp2)-H sulfonylation reaction of styrenes. Styrenes and sulfonyl hydrazides treated with NIS and potassium carbonate in ethanol at 70 °C resulted in (E)-vinyl sulfones exclusively with good to excellent yields. NIS, plays a dual role to generate sulfonyl radical from sulfonyl hydrazides at an initial stage and finally gives β-iodosulfone intermediate which was further converted to (E)-vinyl sulfones. Overall, a sustainable method for mild, metal free, convenient, one pot and direct synthesis of (E)-vinyl sulfones from styrenes are demonstrated via a C−S coupling reaction