Abstract
The reaction of [Rh{(E)-CF[double bond, length as m-dash]CHCF(3)}(PEt(3))(3)] with Zn(CH(3))(2) results in the methylation of the alkenyl ligand to give [Rh{(E/Z)-C(CH(3))[double bond, length as m-dash]CHCF(3)}(PEt(3))(3)]. Variable temperature NMR studies allowed the identification of a heterobinuclear rhodium-zinc complex as an intermediate, for which the structure [Rh(CH(3))(ZnCH(3)){(Z)-C(CH(3))[double bond, length as m-dash]CHCF(3)}(PEt(3))(2)] is proposed. Based on these stoichiometric reactions, unique Negishi-type catalytic cross-coupling reactions of fluorinated propenes by consecutive C-H and C-F bond activation steps at room temperature were developed. The C-H bond activation steps provide a fluorinated ligand at Rh and deliver the fluorinated product, whereas the C-F bond activation and C-C coupling occur via outer-sphere nucleophilic attack at the fluorinated alkenyl ligand.