Ruthenium-Catalyzed Asymmetric Hydrogenation of 3-Oxoglutaric Acid Derivatives: A Study of Unconventional Solvent and Substituent Effects
作者:Wanfang Li、Xiaoming Tao、Xin Ma、Weizheng Fan、Xiaoming Li、Mengmeng Zhao、Xiaomin Xie、Zhaoguo Zhang
DOI:10.1002/chem.201202614
日期:2012.12.14
5‐tricarbonyl substrates in the tested solvents. The C‐2 and C‐4 substituents had notable but irregular influence on the reactivity and enantioselectivity of the reactions. More pronounced solvent effects were observed: the ee values increased from around 20 % in EtOH or THF to 90 % in acetone. Inversion of the product configuration was observed when the solvent was changed from EtOH to THF or acetone
在[RuCl(苯)(S)-SunPhos] Cl(SunPhos =(2,2,2',2'-四甲基-[4,4] '-联苯并[ d ] [1,3]二恶唑] -5,5'-二基)双(二苯基膦))。与简单的β-酮酸衍生物不同,这些高级类似物可在不常见的溶剂(如THF,CH 2 Cl 2)中容易氢化对映选择性高的丙酮,丙酮和二恶烷。已经提出了两个可能的催化循环来解释这些1,3,5-三羰基底物在测试溶剂中的不同反应性。C-2和C-4取代基对反应的反应性和对映选择性具有显着但不规则的影响。观察到更明显的溶剂效应:ee值从EtOH或THF中的约20%增加到丙酮中的90%。当溶剂从EtOH变为THF或丙酮时,观察到产物构型的转化,并且混合溶剂体系比单一溶剂可导致更好的对映选择性。