Nickel-Mediated Trifluoromethylation of Phenol Derivatives by Aryl C-O Bond Activation

The increasing pharmaceutical importance of trifluoromethylarenes has stimulated the development of more efficient trifluoromethylation reactions. Tremendous efforts have focused on copper- and palladium-mediated/catalyzed trifluoromethylation of aryl halides. In contrast, no general method exists for the conversion of widely available inert electrophiles, such as phenol derivatives, into the corresponding trifluoromethylated arenes. Reported herein is a practical nickel-mediated trifluoromethylation of phenol derivatives with readily available trimethyl(trifluoromethyl)silane (TMSCF₃ ). The strategy relies on PMe₃ -promoted oxidative addition and transmetalation, and CCl₃ CN-induced reductive elimination. The broad utility of this transformation has been demonstrated through the direct incorporation of trifluoromethyl into aromatic and heteroaromatic systems, including biorelevant compounds.

Aryl Sulfonium Salts for Site-Selective Late-Stage Trifluoromethylation

Incorporation of the CF₃ group into arenes has found increasing importance in drug discovery. Herein, we report the first photoredox-catalyzed cross-coupling of aryl thianthrenium salts with a copper-based trifluoromethyl reagent, which enables a site-selective late-stage trifluoromethylation of arenes. The reaction proceeds with broad functional group tolerance, even for complex small molecules on gram scale. The method was further extended to produce pentafluoroethylated derivatives.