Impact of Incorporating Substituents onto the P-<i>o</i>-Anisyl Groups of DiPAMP Ligand on the Rhodium(I)-Catalyzed Asymmetric Hydrogenation of Olefins
作者:Borut Zupančič、Barbara Mohar、Michel Stephan
DOI:10.1002/adsc.200800363
日期:2008.9.5
The introduction of 1,2-bis[(o-anisyl)(phenyl)phosphino]ethane (DiPAMP) as a P-stereogenic ligand for rhodium(I)-catalyzed hydrogenation by Knowles et al. came after their evaluation of several diphosphines. However, no in-depth study was carried out on incorporating various substituents on its P-o-anisyl groups. In this work, we have prepared a large series of enantiopure and closely related DiPAMP
Knowles等人引入1,2-双[(邻-茴香基)(苯基)膦基]乙烷(DiPAMP)作为铑(I)催化加氢的P-立体异构体。是他们对几种二膦进行评估后得出的。然而,没有深入研究关于其P-掺入各种取代基进行ö -anisyl基团。在这项工作中,我们制备了一系列对映体纯且密切相关的DiPAMP类似物,它们在o-茴香基环上具有各种取代基(MeO,TMS,t- Bu,Ph,稠合苯环)。新的配体在铑催化的几种模型底物的氢化反应中进行了评估:α-乙酰氨基丙烯酸甲酯,(Z)-α-乙酰氨基甲酸甲酯,(Z)-β-乙酰氨基丁酸巴豆酸酯,衣康酸二甲酯和抗风酸。它们显示出增强的活性和增加的对映选择性,特别是P-(2,3,4,5-四-MeO -C 6 H)取代的配体(4MeBigFUS)。有趣的是,在温和条件下(10 bar H 2,室温),使用Rh-(4MeBigFUS)催化剂在无水酸的氢化中获得了88%ee,而使用