Journal of the American Chemical Society, Vol.130, No.51, 17278-17278, 2008
Unexpected Intermediates and Products in the C-F Bond Activation of Tetrafluorobenzenes with a Bis(triethylphosphine)Nickel Synthon: Direct Evidence of a Rapid and Reversible C-H Bond Activation by Ni(0)
The reaction of (PEt3)(2)Ni(eta(2)-C14H10), a source of the reactive Ni(PEt3)(2) moiety, with 1,2,4,5-F4C6H2 yields a mixture of three C-F bond activation products that include the unexpected products (PEt3)(2)NiF-2,3,5,6-F4C6H and (PEt3)(2)NiF-2,3,5-F3C6H2. Monitoring the reaction mixture via F-19 and H-1 NMR also reveals the presence of the C-H bond activation product, (PEt3)(2)NiH-2,3,5,6-F4C6H which is produced in a rapid equilibrium reaction, This observation provides insight into the steps necessary to modify nickel complexes for selective C-F bond activation in a variety of polyfluorinated aromatic substrates, but also expands the potential of simple nickel compounds for C-H bond activation and functionalization reactions.