Flow electrosynthesis for efficient O-trifluoromethylation of electron-deficient phenols

A sustainable strategy for O-trifluoromethylation of electron-deficient phenols by combining electrochemical synthesis with flow technology is presented. The reaction is optimized by screening experiments to establish a fast and efficient flow protocol. Simultaneous anodic oxidation of Langlois reagent and the phenols in a micro flow cell leads to direct preparation of trifluoromethyl ethers in yields up to 90%. This one-step protocol is tolerant of several functional groups, shows good regioselectivity and works without any chemical oxidants and catalysts by using electrical current as an inexpensive and sustainable reagent.