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(1 H )-ones in good to excellent yields.