Synthesis of Novel Chiral Bisoxazoline Ligands Containing 2,5-Diaryl-1,3,4-oxadiazole and Enantioselective Cyclopropanation of Styrene
作者:Da-Ming Du、Zhan-Yue Wang、Dong-Cheng Xu、Wen-Ting Hua
DOI:10.1055/s-2002-35232
日期:——
Practical synthesis of chiral C 2 -symmetric substituted bisoxazoline ligands containing 2,5-diaryl-1,3,4-oxadiazole units was investigated. Five chiral bisoxazoline ligands containing 2,5-diphenyl-1,3,4-oxadiazole have been synthesized from 2,5-di-(o-carboxylphenyl)-1,3,4-oxadiazole and amino alcohols by methanesulfonyl chloride or p-toluenesulfonyl chloride assisted cyclization via hydroxy amide
研究了含有2,5-二芳基-1,3,4-恶二唑单元的手性C 2 -对称取代双恶唑啉配体的实际合成。五种含有 2,5-二苯基-1,3,4-恶二唑的手性双恶唑啉配体由 2,5-二-(邻羧基苯基)-1,3,4-恶二唑和氨基醇通过甲磺酰氯或对-甲苯磺酰氯通过羟基酰胺中间体辅助环化。对作为手性催化剂的新配体铜配合物在苯乙烯与双唑乙酸乙酯的对映选择性环丙烷化反应中进行了初步研究。观察到反式和顺式-2-苯基环丙烷羧酸盐的对映选择性分别高达 35% ee 和 87% ee。