Palladium(II) complexes of Y,C,Y-chelated phosphines: synthesis, structure, and catalytic activity in Suzuki-Miyaura reaction

摘要

The phosphines L~1PPh2 (1) and L~2PPh2 (2) containing different Y,C,Y-chelating ligands, L~1 = 2,6-(~tBuOCH2)2C6H3-and L~2 = 2,6-(Me2NCH2)2C6H3~-, were treated with PdCl2 and di-μ-chloro-bis[2-[(N,N-dimethylamino)methyl]phenyl-C,N]-dipalladium(II) and yielded complexes trans-{[2,6-(~tBuOCH2)2C6H3]PPh2}2PdCl2 (3), {[2,6-(Me2NCH2)2C6H3]PPh2} PdCl2 (4), {[2,6-(~tBuOCH2)2C6H3]PPh2}Pd(CI)[2-(Me2NCH2)C6H4] (5) and {[2,6-(Me2NCH2)2C6H3]PPh2}Pd(CI)[2-(Me2NCH2)C6H4] (6) as the result of different ability of starting phosphines 1 and 2 to complex PdCl2. Compounds 3-6 were characterized by ~1H, ~(13)C,~(31)P NMR spectroscopy and ESI-MS. The molecular structures of 3,4 and 6 were also determined by X-ray diffraction analysis. The catalytic activity of complexes 3-6 was evaluated in the Suzuki-Miyaura cross-coupling reaction.