C-H and C-F bond activation reactions of pentafluorostyrene at rhodium complexes.

The rhodium(i) complexes [Rh(Bpin)(PEt3)3] (1), [Rh(H)(PEt3)3] (5) and [Rh(Me)(PEt3)3] (14) were employed in reactions with pentafluorostyrene affording coordination of the olefin and C-F or C-H bond activation. Control of the reaction conditions allowed for selective activation reactions at different positions at the fluorinated aromatic ring. The rhodacycle trans-[Rh(F)(CH2CH2(2-C6F4))(PEt3)2] (7) was identified as an intermediate for an activation at the 2-position. Reactivity studies of the latter with CO led to the generation of trans-[Rh(F)(CH2CH2C6F4)(CO)(PEt3)2] (10). Stoichiometric and catalytic hydroboration reactions were achieved using complexes 1 or 5 as catalysts.