Benzimidazoles from Aryl Alkyl Ketones and 2-Amino Anilines by an Iodine Catalyzed Oxidative C(CO)-C(alkyl) Bond Cleavage

Novel molecular iodine catalyzed cyclization reactions of 2-amino anilines with aryl alkyl ketones under oxidant and metal-free conditions are described. The reaction likely involves sequential C-N bond formation followed by C(CO)-C(alkyl) bond cleavage. Various 2-substituted benzimidazoles are obtained in moderate to good yields in a single step from readily available acetophenones, propiophenones, and phenylacetophenones.