Copper-catalyzed synthesis of benzo[b]thiophene-fused imidazopyridines via the cleavage of C–H bond and C–X bond

Abstract

A new and straightforward approach to synthesize benzo[b]thiophene-fused imidazopyridines has been developed by tandem cross-coupling reaction of K2S with 2-(2-bromophenyl)imidazo[1,2-a]pyridines, and K2S as sulfur source constructed double C–S bonds via the cleavage of the C–H bond and the C–X bond. In addition, the optical properties of a library of benzo[b]thiophene-fused imidazopyridines were for the first time fully characterized. Moreover, this synthetic strategy could be applied in the preparation of benzo[b]thiophene-fused indoles.