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 (PEt(3))(2)Ni(eta(2)-C(14)H(10)), a source of the reactive Ni(PEt(3))(2) moiety, with 1,2,4,5-F(4)C(6)H(2) yields a mixture of three C-F bond activation products that include the unexpected products (PEt(3))(2)NiF-2,3,5,6-F(4)C(6)H and (PEt(3))(2)NiF-2,3,5-F(3)C(6)H(2). Monitoring the reaction mixture via (19)F and (1)H NMR also reveals the presence of the C-H bond activation product, (PEt(3))(2)NiH-2,3,5,6-F(4)C(6)H 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.
Johnson
Samuel A
SA
Department of Chemistry and Biochemistry, University of Windsor, Windsor, Ontario, Canada N9B 3P4.
Huff
Carla W
CW
Mustafa
Ferheen
F
Saliba
Mark
M
D002244:Carbon / Q000737:chemistry*; D002384:Catalysis; D002625:Chemistry, Organic / Q000379:methods; D005461:Fluorine / Q000737:chemistry*; D005464:Fluorobenzenes / Q000737:chemistry*; D006859:Hydrogen / Q000737:chemistry*; D007700:Kinetics; D009682:Magnetic Resonance Spectroscopy; D008956:Models, Chemical; D009532:Nickel / Q000737:chemistry*; D010100:Oxygen / Q000737:chemistry; D010720:Phosphines / Q000737:chemistry*
D005464:Fluorobenzenes; D010720:Phosphines; D005461:Fluorine; D002244:Carbon; D009532:Nickel; D006859:Hydrogen; D010100:Oxygen