Ru(II) Catalyzed dehydrogenative annulation of 2-arylimidazo[1,2-a]pyridines with maleimides

Abstract Ru(II) catalyzed annulation of 2-arylimidazo[1,2-a]pyridines with maleimides has been achieved for the synthesis of a diverse range of benzo[e]pyrido[1′,2′:1,2]imidazo[4,5-g]isoindole derivatives. The reaction proceeds through a Ru(II)-catalyzed C H metalation of 2-arylimidazo[1,2-a]pyridine followed by maleimide insertion and intramolecular cyclization. This method is simple and atom-economical to produce the pharmaceutically relevant benzo[e]pyrido[1′,2′:1,2]imidazo[4,5-g]isoindole derivatives with a wide substitution pattern.