Copper‐Mediated Deoxygenative Trifluoromethylation of Benzylic Xanthates: Generation of a CCF 3 Bond from an O‐Based Electrophile

The conversion of an alcohol‐based functional group, into a trifluoromethyl analogue is a desirable transformation. However, few methods are capable of converting O‐based electrophiles into trifluoromethanes. The copper‐mediated trifluoromethylation of benzylic xanthates using Umemoto’s reagent as the source of CF 3 to form CCF 3 bonds is described. The method is compatible with an array of benzylic xanthates bearing useful functional groups. A preliminary mechanistic investigation suggests that the CCF 3 bond forms by reaction of the substrate with in situ generated CuCF 3 and CuOTf. Further evidence suggests that the reaction could proceed via a radical cation intermediate.