Transition-metal-free access to benzyl ethers via aerobic cross-dehydrogenative coupling of benzylic C(sp3)–H bonds with alcohols

Abstract

We have developed a practical KOtBu- or KOH-catalyzed aerobic cross-dehydrogenative coupling of benzylic C(sp³)–H bonds with various alcohols utilizing molecular oxygen as the sole oxidant. This transition-metal-free and chemical-oxidant-free methodology could enable direct and selective alkoxylation of benzylic C(sp³)–H bonds, especially the primary benzylic C–H bond, which is prone to undergo overoxidation. Moreover, the aerobic oxidative C–H/O–H cross-coupling approach provides a practical and sustainable pathway to construct benzyl ethers with high chemoselectivity under mild reaction conditions.