Copper-Catalyzed Multicomponent Reactions (MCRs) for Disulfenylation of Imidazo[1,2-<i>a</i>]pyridines Using Elemental Sulfur and Arylhalides and Intramolecular Cyclization of Haloimidazo[1,2-<i>a</i>]pyridines

Abstract

Copper-catalyzed synthesis of disulfenylated imidazo[1,2-<i>a</i>]pyridines and indoles using elemental sulfur and haloarenes through one-pot, three component reaction by two C-S-C bond formations has been developed. The method has a broad substrate scope with a variety of substituted haloarenes. The conditions were also applied for the synthesis of benzothieno-imidazo[1,2-<i>a</i>]pyridines in excellent yields (99%) through intramolecular sulfenocyclization of 2-(2-halophenyl)imidazo[1,2-<i>a</i>]pyridines using sulfur powder.