ARS–TiO2 photocatalyzed direct functionalization of sp2 C–H bonds toward thiocyanation and cyclization reactions under visible light†
An ARS–TiO2 photocatalyst has been prepared, by a simple method through stirring a mixture of ARS and TiO2 at room temperature in the dark, to extend the photocatalytic response of titanium dioxide toward the visible light spectrum. The synergic effect of ARS and TiO2 in the photocatalyst system has catalyzed direct C–H functionalization of sp2 C–H bonds toward thiocyanation and cyclization reactions. Several aromatic and heteroaromatic scaffolds (2-phenylamino-thiazole, phenol, aniline, indole and pyrrole derivatives) were treated with the thiocyanate anion at room temperature. Herein, the first report on thiocyanation of phenol and synthesis of 2-aminobenzothiazole derivatives under visible light is presented.