Visible Light Photoredox‐Catalyzed Arylation of Quinoxalin‐2(1H)‐ones with Aryldiazonium Salts

Abstract A visible light photoredox‐catalyzed C‐3 arylation of quinoxalin‐2(1 H )‐ones with aryldiazonium tetrafluoroborates has been developed. The reaction was effectively accelerated using an inexpensive eosin Y as a photoredox catalyst under visible‐light irradiation without any other metal, oxidant, or additive. This approach offers a facile way to prepare 3‐arylquinoxalin‐2(1 H )‐one derivatives with a wide range of functional group tolerance.