New Radical Route and Insight for the Highly Efficient Synthesis of Benzimidazoles Integrated with Hydrogen Evolution

Abstract

AbstractBenzimidazoles are a versatile class of scaffolds with important biological activities, whereas their synthesis in a lower‐cost and more efficient manner remains a challenge. Here, we demonstrate a conceptually new radical route for the high‐performance photoredox coupling of alcohols and diamines to synthesize benzimidazoles along with stoichiometric hydrogen (H2) over Pd‐decorated ultrathin ZnO nanosheets (Pd/ZnO NSs). The mechanistic study reveals the unique advantage of ZnO NSs over other supports and particularly that the features of Pd nanoparticles in facilitating the cleavage of the α‐C−H bond of alcohols and adsorbing subsequently‐generated C‐centered radicals hold the key to turning on the reaction. This work highlights a new insight into radical‐induced efficient benzimidazole synthesis pairing with H2 evolution by rationally designing semiconductor‐based photoredox systems.