Synthesis of Pyrrolone‐ and Isoindolinone‐Fused Benzimidazole‐4,7‐diones by Stepwise Palladium‐Catalyzed Carbonylative Cyclization and Oxidation

2‐(2‐Bromovinyl)‐ and 2‐(2‐bromoaryl)‐4,7‐dimethoxybenzimidazoles react with carbon monoxide (10 atm) in toluene in the presence of a catalytic amount of PdCl 2 and PPh 3 along with NaOAc to produce the corresponding pyrrolone‐ and isoindolinone‐fused 4,7‐dimethoxybenzimidazoles, respectively, in good yields. Oxidation of such binuclear N‐fused hybrid scaffolds with ceric ammonium nitrate in acetonitrile‐H 2 O gives unprecedented pyrrolone‐ and isoindolinone‐fused benzimidazole‐4,7‐diones in high yields.