Visible Light-Induced Metal-Free Benzylation of Quinones via Cross Dehydrogenation Coupling Reaction

Benzylated quinones widely exist in natural products and drug molecules. Thus their convenient synthesis with high efficiency brings great significance. However, hard conditions are still essential among the present reports. Herein, the development of visible light-induced metal-free benzylation of quinones via cross dehydrogenation coupling reaction with methylene blue as photocatalyst, tert-butyl hydroperoxide as oxidant, and toluene derivatives as benzylation reagent is reported. The reaction exhibits many advantages, including mild conditions, a broad scope with good functional group tolerance, low cost, and avoidance of metal remaining in products. This method may bring novel inspiration and approach for synthesis of bioactive quinones.