Catalyzing the Hydrodefluorination of CF 3 -Substituted Alkenes by PhSiH 3 . H• Transfer from a Nickel Hydride

The hydrodefluorination of CF 3 -substituted alkenes can be catalyzed by a nickel(II) hydride bearing a pincer ligand. The catalyst loading can be as low as 1 mol%. gem -Difluoroalkenes containing a number of functional groups can be formed in good to excellent yields by a radical mechanism initiated by H• transfer from the nickel hydride. The relative reactivity of various substrates supports the proposed mechanism, as does a TEMPO trapping experiment.