Visible‐Light‐Induced Carbopyridylation of Maleimides with Pyridine Salts Under Catalyst‐Free Conditions

A catalyst‐free carbopyridylation reaction of maleimides with N‐benzoylmethylpyridinium bromides under visible light irradiation is reported. The carbo‐2‐pyridylation products of maleimides are obtained in good yields, demonstrating broad substrate scope and high functional group tolerance even on a gram scale. Mechanistic studies suggest that the process involves a tandem [3+2] cycloaddition, and Norrish‐type‐II fragmentation.