Development of Novel Chiral Synthon by Using Cationic Palladium Complexes

三酸钯与2种等量的双齿膦配体R_2P(CH_2)_nPR_2 （n=1,2,3）反应，得到了高收率的阳离子三酸钯配合物L_2Pd^<2+>(OTf)_2。与4种等量的单齿膦R_3P反应，得到与乙腈的阳离子钯配合物（R_3P）_<4-n> (CH_3CN)_nPd^<2+>(OTf)_2。根据膦的结构不同，这些配合物与乙腈的结构也不同。例如，在三（正丁基）膦的情况下得到四（三丁基）膦配合物，在Ph_3P或（t-Bu）_3P的情况下得到三（三苯基）或三（三-丁基）膦配合物。与（i-Pr）_3P和（c-Hex）_3P反应得到了与2个膦的配合物。对所得到的配合物进行^<31>P核磁共振研究发现，这些配合物在乙腈溶液中以动态平衡混合物的形式存在。研究结果发表在1998年东京国际有机金属化学研讨会上。研究了膦配体配合物对环戊二烯加氢反应和聚合的催化性质。在氢硅硫化方面的应用正在研究中。以旋光性樟脑磺酸为原料制备了手性烷磺酸。

Reactions of palladium triflate with 2 equiv. of didentate phosphine ligands, R_2P(CH_2)_nPR_2 (n=1,2,3), afforded cationic palladium triflate complexes, L_2Pd^<2+>(OTf)_2, in high yields. Reactions with 4 equiv. of monodentate phosphines, R_3P, gave cationic palladium complexes with acetonitrile, (R_3P)_<4-n> (CH_3CN)_nPd^<2+>(OTf)_2. Depending on the structure of phosphines, structures of these complexes with acetonitrile were different. For example, the tetrakis(tributyl)phosphine complex was obtained in the case of tri(n-butyl)phosphine, and tris(triphenyl) or tris(tri t-butyl)phosphine comples were obtained in the case of Ph_3P or (t-Bu)_3P.The complexes with 2 phosphines were obtained from reactions with (i-Pr)_3P and (c-Hex)_3P.It is found by ^<31>P NMR studies on the obtained complexes that those complexes existed as dynamic equiriblium mixture in acetonitrile solutions. The results were reported in 45^<th> symposium for organometallic chemistry (1998, Tokyo).Catalytic natures of the complexes with didentate phosphine ligands toward hydroslufination and polymerization of cyclopentadiene were found. Application to hydrosilasulfination was under investigation. A chiral alkanesulfinic acid was prepared from optically active camphorsulfonic acid.