Chromium-Catalyzed Cross-Electrophile Couplings of Trifluoromethyl Alkenes with Benzyl Halides

The cross-electrophile couplings of trifluoromethyl alkenes with benzyl halides could be successfully achieved in tetrahydrofuran (THF) in the presence of chromium(III) chloride, magnesium turnings, and lithium chloride. The defluorinative mono-benzylation proceeded efficiently at room temperature via C–F bond cleavage, affording a broad range of synthetically valuable gem-difluoroalkenes in moderate to good yields. The approach exhibited wide substrate generality and good functional group compatibility. Synthetic utilities of the method were demonstrated by scale-up synthesis and late-stage elaboration of bioactive molecules. Mechanistic studies indicated that in situ generated benzylmagnesium species might function as the key intermediate of the coupling protocol.