Visible-Light-Driven Modular Synthesis of Isoquinolinone Derivatives via Palladium-Catalyzed Radical <i>6-endo</i> Annulation of Aryl Halides

Herein, a photoexcited-state palladium-catalyzed <i>6-endo</i> selective annulation reaction of aryl-halide-tethered enamides has been developed, allowing various isoquinolinone motifs synthesized under mild conditions. This approach features operational simplicity, broad substrate scope, good functional group tolerance, and high chemo- and regioselectivity. The synthetic versatility of this methodology is underscored by scalable synthesis and downstream derivatization. Mechanistic studies reveal that this protocol involves a hybrid Pd-radical pathway and that the nitrogen atom is crucial for the observed <i>endo</i> selectivity.