A Novel Process for Selective Ruthenium-Catalyzed Oxidation of Naphthalenes and Phenols

Arenes are selectively oxidized to the corresponding quinones employing ruthenium(2,2',6':2-terpyridine)(2,6-pyridinedicarboxylate) [Ru(tpy)(pydic] as catalyst and hydrogen peroxide as the terminal oxidant. Applying alkylated naphthalenes and phenols, benzo- and naphthoquinones are obtained in up to 93% yield. The industrially interesting oxidation of 2-methylnaphthalene gave 74% of the corresponding quinones and 60% of menadione (vitamin K(3)). 2,3,5-Trimethylbenzoquinone which constitutes the key intermediate for vitamin E is obtained in 83% yield.