Combined experimental/theoretical study on d-glucosamine promoted regioselective sulfenylation of indoles catalyzed by copper

Abstract

A combined experimental/theoretical investigation on the D-glucosamine promoted sulfenylation of indoles at the C3 position with sodium sulfinates catalyzed by copper is presented. The C3-sulfenylation of indoles shows good functional-group tolerance and yields. The 3-I-indole was identified as a crucial intermediate in the catalytic cycle. The catalytic role of [Cu(DMSO)₂]²⁺ was addressed using quantum chemical calculations. In the interaction of [Cu(DMSO)₂]²⁺ with indole, the [Cu(DMSO)₂]²⁺ complex abstracts a hydrogen from the C3 of indole. The electronic origin for selective C–H bond activation of indole was revealed.