Electrochemically mediated fluoroalkylation/cyclization of unactivated alkenes: synthesis of polycyclic benzimidazoles containing a CF3 group

Abstract

Herein, an electrochemical trifluoromethylation/cyclization reaction of unactivated alkenes within benzimidazole molecules by direct cascade with C2–H has been developed. The protocol used the readily available CF₃SO₂Na as the trifluoromethylation reagent. A variety of polycyclic benzimidazoles were successfully synthesized under transition metal- and oxidant-free conditions in 34–78% yields. In addition, the reaction was characterized by good regioselectivity, a wide range of substrates and scalability.