Photoinduced decarboxylative radical cascade alkylation/cyclization of benzimidazole derivatives with an aliphatic carboxylic acid via ligand-to-iron charge transfer

Abstract

The photoinduced decarboxylative radical cascade alkylation/cyclization strategy of diverse benzimidazoles containing unactivated alkene moieties towards the synthesis of polycyclic benzimidazoles via ligand-to-metal-charge-transfer (LMCT) has been developed. Specifically, the reaction initiates the decarboxylation of alkyl carboxylic acids through light-induced charge transfer from the ligand to iron, resulting in the formation of alkyl radical centers. Moreover, the protocol has prominent features, such as a broad substrate scope, high regioselectivity, mild reaction conditions, operational simplicity and readily available air acting as the sole oxidant.