Facile synthesis of C2-symmetric tridentate bis(thiazoline) and bis(oxazoline) ligands and their application in the enantioselective Henry reaction
作者:Shao-Feng Lu、Da-Ming Du、Shi-Wei Zhang、Jiaxi Xu
DOI:10.1016/j.tetasy.2004.09.011
日期:2004.11
A series of novel C2-symmetric bis(thiazoline) ligands with a diphenylamine backbone as a linkage between two thiazoline rings were synthesized by the use of the simple reagent phosphorus pentasulfide. Their application in the catalytic asymmetric Henry reaction of α-keto esters was investigated with comparison to the corresponding bis(oxazoline) ligands. Cu(II)–bis(oxazoline) complexes furnished moderate
通过使用简单的五硫化二磷试剂合成了一系列新颖的C 2对称的双(噻唑啉)配体,其具有二苯胺骨架作为两个噻唑啉环之间的连接。与相应的双(恶唑啉)配体比较,研究了它们在α-酮酯催化不对称亨利反应中的应用。Cu(II)-双(恶唑啉)络合物具有中等的对映选择性(可达60%ee),而Cu(II)-双(噻唑啉)络合物对纯硝基甲烷具有更高的对映选择性(高达ee的70%)。当使用诸如CH 2 Cl 2的卤代溶剂时(高达82%ee),对映选择性得到改善,但所得收率低于纯反应的收率。