C-H and C-F Bond Activation Reactions of Fluorinated Propenes at Rhodium: Distinctive Reactivity of the Refrigerant HFO-1234yf

The reaction of [Rh(H)(PEt3)(3)] (1) with the refrigerant HFO-1234yf (2,3,3,3-tetrafluoropropene) affords an efficient route to obtain [Rh(F)(PEt3)(3)] (3) by C-F bond activation. Catalytic hydrodefluorinations were achieved in the presence of the silane HSiPh3. In the presence of a fluorosilane, 3 provides a C-H bond activation followed by a 1,2-fluorine shift to produce [Rh{(E)-C(CF3)=CHF}(PEt3)(3)] (4). Similar rearrangements of HFO-1234yf were observed at [Rh(E)(PEt3)(3)] [E=Bpin (6), C7D7 (8), Me (9)]. The ability to favor C-H bond activation using 3 and fluorosilane is also demonstrated with 3,3,3-trifluoropropene. Studies are supported by DFT calculations.