通过液相策略以高收率合成了一种新型的手性二膦PyrPhos功能化共聚酯。生成的树枝状PyrPhos配体通过简单的溶剂沉淀法纯化,无需进行色谱分离,并通过1 H,13 C和31 P NMR,MALDI-TOF质谱以及元素分析进行了很好的表征。他们的铑配合物用于α的不对称氢化乙酰胺基肉桂酸。获得了优异的对映选择性,这与使用相应的小分子催化剂的对映选择性相当。另外,这些共聚体催化剂表现出比具有位于聚(芳基醚)树突的焦点处或聚(丙烯亚胺)树状体的外围的Rh(PyrPhos)位点的树状聚合物催化剂更好的催化性能。
Synthesis and application of peripherally alkyl-functionalized dendritic pyrphos ligands: Homogeneous-supported catalysts for enantioselective hydrogenation
作者:Bing Yi、Hua-Ping He、Qing-Hua Fan
DOI:10.1016/j.molcata.2009.09.004
日期:2010.1
A new series of dendritic ligands with a chiral diphosphine located at the focal point have been synthesized through coupling of (R, R)-3,4-bis(biphenylphosphino)pyrrolidine (pyrphos) with peripherally alkyl-functionalized benzoic acid dendrons. These ligands were employed in the Rh-catalyzed asymmetric hydrogenation of prochiral dehydroamino acids, exhibiting excellent catalytic activities and enantioselectivities. The second-generation dendritic catalyst could be recovered by simple liquid-liquid biphasic separation and reused four times without serious loss of its activity and selectivity. (C) 2009 Elsevier B.V. All rights reserved.