Palladium-catalyzed carbonylative cyclization of 2-(2-bromovinyl)benzimidazoles leading to pyrrolone-fused benzimidazoles

• Palladium-catalyzed carbonylation with carbon monoxide followed by cyclization.
• Synthesis of a new class of pyrrolone-fused benzimidazoles starting from readily available ketones.
• Synthesis of N-fused heterocycles via carbonylative cyclization of 2-(2-bromovinyl)benzimidazoles.

2-(2-Bromovinyl)benzimidazoles are carbonylatively cyclized under carbon monoxide pressure in toluene in the presence of a catalytic amount of PdCl2 and PPh3 along with a base to give 1H-benzo[d]pyrrolo[1,2-a]imidazolones in good yields.

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