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

We have developed a practical KOtBu- or KOH-catalyzed aerobic cross-dehydrogenative coupling of benzylic C(sp(3))-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(sp(3))-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.