Ferrocene/air double-mediated FeTiO 3 -photocatalyzed semi-heterogeneous annulation of quinoxalin-2(1 H )-ones in EtOH/H 2 O.

With both ferrocene and air as the redox catalysts, for the first time, the low-cost natural ilmenite (FeTiO 3 ) was successfully used for photocatalytic bond formations. Under the assistance of a traceless H-bond, and HCHO as the methylene reagent, a variety of imidazo[1,5- a ]quinoxalinones were semi-heterogeneously photosynthesized in high yields with good functional group compatibility.