The reaction of [Rh(H)(PEt ) ] (1) with the refrigerant HFO-1234yf (2,3,3,3-tetrafluoropropene) affords an efficient route to obtain [Rh(F)(PEt ) ] (3) by C-F bond activation. Catalytic hydrodefluorinations were achieved in the presence of the silane HSiPh . 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(CF )=CHF}(PEt ) ] (4). Similar rearrangements of HFO-1234yf were observed at [Rh(E)(PEt ) ] [E=Bpin (6), C D (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.