Acid-Promoted Selective Carbon-Fluorine Bond Activation and Functionalization of Hexafluoropropene by Nickel Complexes Supported with Phosphine Ligands

作者：Xu, Wengang; Sun, Hongjian; Xiong, Zichang; Li, Xiaoyan^*

来源：Organometallics, 2013, 32(23): 7122-7132.

DOI：10.1021/om400782v

• C-F ACTIVATION
• CATALYTIC HYDRODEFLUORINATION
• MAGNETIC-RESONANCE
• RHODIUM
• FLUOROOLEFINS
• REACTIVITY
• PLATINUM
• PENTAFLUOROPYRIDINE
• TETRAFLUOROETHYLENE
• FLUOROCARBONS

The electron-rich complex Ni(PMe3)(4) was utilized to react with perfluoropropene to obtain Ni(CF2=CFCF3)(PMe3)(3) (1). The selective C-F bond activation process of the pi-coordinated perfluoropropene in 1 was conducted with the promotion of Lewis acids (ZnCl2, LiBr, and LiI) under mild conditions to afford the products Ni(CF3C=CF2)(PMe3)(2)X (X = Cl (2), Br (3), 1 (4)). The structures of complexes 2 and 3 determined by X-ray single-crystal diffraction confirmed that the C-F bond activation occurred at the geminal position of the trifluoromethyl group. Surprisingly, CF3COOH as a protonic acid could also carry out a similar activation reaction to give rise to Ni(CF3C=CF2)(CF3COO)(PMe3)(2) (7), while only the addition products Ni(CF2CFHCF3)(CH3COO)(PMe3) (5) and Ni(CF2CFHCF3)(CH3SO3)(PMe3) (6) were obtained with CH3COOH and CH3SO3H. The transmetalation products Ni(CF3C=CF2)Ph(PMe3)(2) (8), Ni(CF3C=CF2)(p-MeOPh)(PMe3)(2) (9), and Ni(CF3C=CF2)(C=CPh)(PMe3)(2) (10) were obtained through the reactions of Ni(CF3C=CF2)(PMe3)(2)Cl (2) with PhMgBr, (p-MeOPh)MgBr, and PhC=CLi. In contrast, the reaction of complex 2 with PhCH2CH2MgBr delivered complex 11, Ni(CF3CH=C-CH2CH2Ph)(PMe3)(2), via double C-F bond activation. All of the C(sp(2))-F bonds in complex 11 were activated and cleaved. The structures of complexes 5 and 7-11 were determined by X-ray single-crystal structure analysis. A reasonable mechanism was proposed and partially experimentally verified through operando IR and in situ H-1 NMR spectroscopy.

• 出版日期2013-12-9
• 单位山东大学