A benzimidazole-based Cu(ii) complex catalyzed site-selective C–H sulfenylation of imidazo-[1,2-a]pyridines using CS2 as a sulfur source

Abstract

A new benzimidazole-based Cu(II) complex catalyzed site-selective sulfenylation of imidazo[1,2-a]pyridines with benzyl/alkyl/allyl bromides and CS₂ at 100 °C in DMF : H₂O is reported. The present methodology has been developed for the synthesis of 3-sulfenyl imidazo[1,2-a]pyridines in good yields with a broad substrate scope. In this protocol, CS₂, commonly known as a non-polar small molecule bioregulator (SMB), is converted to valuable sulfenylated imidazo[1,2-a]pyridine derivatives. In addition, theoretical investigations along with experimental evidence unfold the insights into the probable mechanistic pathway of site-selective sulfenylation from S,S-dibenzyltrithiocarbonate, which is particularly formed as an intermediate during the reaction.