C-F Activation and hydrodefluorination of fluorinated alkenes at rhodium

摘要

Reaction of [RhH(PEt_3)_4] (9) with hexafluoropropene (1) affords the C-F activation product [Rh{(Z)-CF = CF(CF_3)}(PEt_3)_3] (4) as well as Et_3P(F){(Z)-CF=CF(CF_3)} (110. In contrast, addition of (E)-1,2,3,3,3--pentafluoropropene (8) to 9 yields [Rh{(E)-C(CF_3) = CHF}(PEt_3)_3] (12) together with [RhF(PEt_3)_3] (6) and (Z)-1,1,3,3-tetrafluoropropene (10). Treatment of 12 with hydrogen effects the formation of 1,1,1-trifluoropropane (2) and the fluoro compounds [RhF(PEt_3)_3] (6) and cis-mer-[Rh(H)_2F(PEt_3)_3] (7). On treatment of 6 or of a mixture of 6 and 7 with HSiPh_3 the complexes [RhH(PEt_3)_3] (3) and cis-fac-[Rh(H)_2(SiPh_3)_3] (13) are obtained. Both compounds are capable of the C-F activation of hexafluoropropene (1) to afford 4. The molecular structure of complex 13 has been determined by X-ray crystallography.