Visible light-driven difluoroalkoxylation of imidazopyridines using n-fluorobenzenesulfonimide as fluorinating agent

Abstract

A visible-light-promoted site-selective difluoroalkoxylation of imidazo[1,2-a]pyridines has been achieved using N-fluorobenzenesulfonimide (NFSI) as a fluorinating agent. This practical reaction has a wide range of substrate scope for both imidazo[1,2-a]pyridines and alcohols to give 3,3-difluoro-2-alkoxy-2-arylimidazo[1,2-a]pyridines in 65–93% yields. The reaction proceeded at room temperature, showed high functional group tolerance, and was amenable to scale-up. Based on mechanistic investigation, a radical pathway is proposed.