Aminophosphine-palladium(II) complexes: Synthsesis, structure and applications in Suzuki and Heck cross-coupling reactions

摘要

Reaction of furfurylamine with 1 or 2 equivalents of PPh_2Cl in the presence of Et_3N, proceeds under anaerobic conditions in thf to give furfuryl-2-(N-diphenylphosphino)amine, Ph_2PNHCH _2~-C_4H_3O, 1 and furfuryl-2-(N,N- bis(diphenylphosphino)amine), (Ph_2P)_2NCH _2~-C_4H_3O, 2, respectively. The reactions of 1 and 2 with MCl_2(cod) (M = Pd, Pt; cod = 1,5-cyclooctadiene) or Pt(CH_3)_2(cod) yield complexes [M(Ph_2PNHCH _2-C_4H_3O)_2Cl_2] (M = Pd 1a, Pt 1b), [Pt(Ph_2PNHCH_2~-C_4H_3O) _2(CH_3)_2] (1c), and [M((Ph_2P) _2NCH_2~-C_4H_3O)Cl_2] (M = Pd 2a, Pt 2b), [Pt((Ph_2P)_2NCH_2~-C_4H _3O)(CH_3)_2] (2c), respectively. All the compounds were isolated as analytically pure substances and characterized by NMR, IR spectroscopy and elemental analysis. Representative solid-state structures of 2a and 2b were also determined by X-ray single crystal diffraction technique. Furthermore, the palladium complexes 1a and 2a were tested and found to be highly active catalysts in the Suzuki coupling and Heck reaction affording biphenyls and trans-stilbenes, respectively.