Synthesis of platinum complexes containing (+)-bornyl- and (−)-menthylammonium in the outer coordination sphere and their catalytic activity in hydrosilylation reactions
作者:D. A. de Vekki、V. M. Uvarov、A. N. Reznikov、N. K. Skvortsov
DOI:10.1007/s11172-008-0054-3
日期:2008.2
Optically active (+)-bornyl- and (−)-menthylammonium platinates were synthesized starting from H2[PtCl6] · 4H2O and hydrochlorides of the corresponding amines. Catalytic activity of the complexes in the hydrosilylation reactions of 1,3-divinyl-1,1,3,3-tetramethyldisiloxane with 1,1,3,3-tetramethyldisiloxane and acetophenone with diphenylsilane was studied. The addition of the siloxanes leads to a predominant formation of β-adduct. Activity of the catalysts, evaluated on the 50% conversion of the substrate, decreases in the following sequence: (−)-(menthylNH3)2[PtCl6] > (Et3NH)2[PtCl6] > (+)-(bornylNH3)2[PtCl4] > (+)-(bornylNH3)2[PtCl6]. Asymmetric induction is observed in the hydrosilylation of aceto-phenone in the presence of (+)-(bornylNH3)2[PtCl n ] (n = 4, 6); (+)-(bornylNH3)2[PtCl6] showed the highest catalytic activity and selectivity. The hydrosilylation of acetophenone gave 1-phenylethoxy(diphenyl)silane, 1-phenylvinyloxy(diphenyl)silane, and 2-phenylethyl-2-diphenylsiloxy(diphenyl)silane as the products.
合成了光学活性的 (+)-博尔尼酯铵铂盐和 (−)-薄荷铵铂盐,起始材料为 H2[PtCl6] · 4H2O 和相应胺的盐酸盐。研究了这些配合物在 1,3-二乙烯基-1,1,3,3-四甲基二硅氧烷与 1,1,3,3-四甲基二硅氧烷及乙酰苯与二苯基硅烷的氢硅化反应中的催化活性。硅氧烷的添加优先形成 β-加成物。催化剂的活性经过评估以 50% 底物转化率表示,活性顺序为: (−)-(薄荷基NH3)2[PtCl6] > (Et3NH)2[PtCl6] > (+)-(博尔尼基NH3)2[PtCl4] > (+)-(博尔尼基NH3)2[PtCl6]。在 (+)-(博尔尼基NH3)2[PtCl n ] (n = 4,6) 存在下,观察到氢硅化反应中的不对称诱导;(+)-(博尔尼基NH3)2[PtCl6] 显示出最高的催化活性和选择性。乙酰苯的氢硅化反应生成的产物包括 1-苯乙氧基(双苯基)硅烷、1-苯乙烯氧基(双苯基)硅烷和 2-苯乙基-2-双苯基硅氧基(双苯基)硅烷。