Tetrabutylammonium Iodide Catalyzed Epoxidation of Naphthoquinone Derivatives with tert-Butyl Hydroperoxide as an Oxidant

An efficient and environmentally benign procedure has been developed for the epoxidation of naphthoquinone derivatives by using tetrabutylammonium iodide as a catalyst and tert-butyl hydroperoxide as an oxidant in the presence of silicon dioxide. This protocol, which provides a facile base-free methodology for the synthesis of some new naphthoquinone-based epoxides, features mild reaction conditions, high yields, remarkably short reaction time, and broad substrate scope