Synthesis and reactivity of bis(diphenylphosphino)amine ligands and their application in Suzuki cross-coupling reactions

Two new bis(diphenylphosphino)amines, N,N-bis(diphenylphosphino)benzidine 1 and N,N-bis(diphenylphosphino)-3,3-dimethoxybenzidine 2 were prepared by aminolysis. Their corresponding oxides, sulfides and selenides were readily prepared by reaction with hydrogen peroxide, elemental sulfur or grey selenium, respectively. Symmetric dinuclear palladium and platinum complexes were also isolated from the reaction with [M(cod)Cl2] (M = Pd or Pt, cod = cycloocta-1,5-diene). All compounds were characterized by IR and NMR spectroscopy and elemental analysis and the structure of [(Ph2P)2N–C6H4–C6H4–N(PPh2)2] was determined by single crystal X-ray diffraction. The catalytic activity of palladium complexes in Suzuki coupling reactions was also investigated.

Two new bis(diphenylphosphino)amines, N,N-bis(diphenylphosphino)benzidine 1 and N,N-bis(diphenylphosphino)-3,3-dimethoxybenzidine 2 were prepared by aminolysis. Their palladium and platinum complexes were isolated from the reaction with [M(cod)Cl2] (M = Pd or Pt, cod = cycloocta-1,5-diene). The catalytic activity of palladium complexes in Suzuki coupling reactions was also investigated.Figure optionsDownload as PowerPoint slideHighlights
► Two new bis(phosphino)amines have been synthesized.
► While the ligands are unstable in solution, the metal complexes are air stable.
► Pd complexes were evaluated in Suzuki coupling reactions.
► In general, excellent conversions to the cross-coupling biaryl product are observed.