Reactions of iridium(fluoroalkyl)hydride complexes Cp*Ir(PMe
3)(CF
2R
F)Y (R
F = F, CF
3; Y = H,D) with LutHX (Lut = 2,6-dimethylpyridine; X = Cl, I) results in C-F activation coupled with hydride migrationto give Cp*Ir(PMe
3)(CYFR
F)X as variable mixtures of diastereomers. Solution conformations and relativediastereomer configurations of the products have been determined by
19F{
1H}HOESY NMR to be (
SC,
SIr)(
RC,
RIr) for the kinetic diastereomer and (
RC,
SIr)(
SC,
RIr) for its thermodynamic counterpart. Isotopelabeling experiments using LutDCl/Cp*Ir(PMe
3)(CF
2R
F)H and Cp*Ir(PMe
3)(CF
2R
F)D/LutHCl) showed that,unlike a previously studied system, H/D exchange is faster than protonation of the
![](/images/gifchars/alpha.gif)
-CF bond, giving anidentical mixture of product isotopologues from both reaction mixtures. The kinetic rate law shows a first-order dependence on the concentration of iridium substrate, but a half-order dependence on that of LutHCl;this is interpreted to mean that LutHCl dissociates to give HCl as the active protic source for C-F bondactivation. Detailed kinetic studies are reported, which demonstrate that lack of complete diastereoselectivityis not a function of the C-F bond activation/H migration steps but that a cationic intermediate plays adouble role in loss of diastereoselectivity; the intermediate can undergo epimerization at iridium beforebeing trapped by halide and can also catalyze the epimerization of kinetic diastereomer product tothermodynamic product. A detailed mechanism is proposed and simulations performed to fit the kineticdata.