Iodine‐Catalyzed C−H Functionalization of Cyclopentenedione with Benzamidine: A Double Dehydrogenative Oxidative Cyclization to Access Fused Imidazoles

Abstract A double C−H functionalization of cyclopentenedione with benzamidine hydrochloride catalyzed by iodine has been disclosed for synthesizing fused imidazole derivatives. This methodology leads to a variety of fused imidazole derivatives and requires a sub‐stoichiometric amount of iodine as a catalyst and aqueous tert‐butyl hydroperoxide (TBHP) as an oxidant. This reaction involves a double‐cross dehydrogenative coupling (CDC) of 1,3‐cyclopentenedione and benzamidine hydrochloride to form two C−N bonds in a consecutive manner within short reaction time. A plausible mechanism has been proposed based on the mass spectrometric analysis. magnified image