Highly efficient copper-catalyzed benzylic C–H alkoxylation with NFSI

A sacrificial reductant-free copper-catalyzed benzylic C–H alkoxylation with N-Fluorobenzenesulfonimide (NFSI) was reported. Mechanistic studies suggested a novel pathway for the generation of active Cu^I species from Cu(OAc)₂, NFSI and MeOH. A proper loading amount of copper catalyst was found to balance the reaction rates of benzylic C–H alkoxylation and overoxidation of benzyl ether to exhibit the best performance.