Metal-free visible-induced C(sp(2))–C(sp(2)) coupling of quinoxalin-2(H)-ones via oxidative cleavage of the C–N bond

A C(sp(2))–C(sp(2)) reaction between aromatic hydrazines and quinoxalines has been developed through a photocatalytic system. The protocol is established for C(sp(2))–N bond cleavage and direct C(sp(2))–H functionalization for the coupling of C(sp(2))–C(sp(2)) via photocatalysis under mild and ideal air conditions without the presence of a strong base and metal. The mechanistic studies reveal that the generation of a benzene radical via the oxidative cleavage of aromatic hydrazines for the cross-coupling of C(sp(2))–C(sp(2)) with the assistance of a photocatalyst is essential. The process exhibits excellent compatibility with functional groups and provides convenient access to various 3-arylquinoxalin-2(1H)-ones in good to excellent yields.