Sulfated tungstate/dioxygen: a new catalytic system for oxysulfonylation of styrenes to form β-keto sulfones

Abstract

A new system for synthesis of a wide range of β-keto sulfones using sulfated tungstate as a heterogeneous catalyst and oxygen as an environmentally benign oxidant with aryl hydrazides and styrenes as reacting counterparts has been developed. The preliminary experimental results support the involvement of free radical species. Thus, aryl sulfonyl free radicals, generated by oxidation of aryl sulfonyl hydrazides, subsequently undergo a tandem addition to styrenes to form intermediate benzyl free radicals, and oxygen capture and oxidation to furnish β-keto sulfones. The method is mild and efficient with easy workup procedures. The catalyst is recyclable.