Synthesis of (2S,1′R,2′R,3′R)-2-(2′,3′-Dicarboxycyclopropyl)-glycine via the Stereochemically Controlled Cyclopropanation of (S)-Glyceraldehyde Acetonide-Derived Enones
作者:Dawei Ma、Yeyu Cao、Wengen Wu、Yongwen Jiang
DOI:10.1016/s0040-4020(00)00677-3
日期:2000.9
The reaction of ethyl dimethylsulfonium acetate bromide with aromatic enones 5a or 5b derived from (S)-glyceraldehyde acetonide under the action of DBU provides cyclopropanation products in excellent yield and good diastereoselectivity (10/1). High geometry-selectivity (>95/1) can be reached when the reaction is carried out at lower temperature in toluene. The cis-enone 5a gives better geometry-selectivity
在DBU的作用下,乙基二甲基acetate乙酸溴化乙铵与衍生自(S)-甘油醛丙酮化物的芳族烯酮5a或5b的反应提供了优异的收率和良好的非对映选择性(10/1)的环丙烷化产物。当反应在较低温度下在甲苯中进行时,可以达到较高的几何选择性(> 95/1)。该顺-enone 5A提供了更好的几何选择性比反式-enone 5B。具有酰胺基的酰化物也可以用于环丙烷化反应,但是产率或几何选择性都不令人满意。基于该反应,针对(2 S,1'[R,2' - [R,3' - [R)-2-(2',3'-dicarboxycyclopropyl)甘氨酸(L-DCG-IV),代谢型谷氨酸的同种型选择性激动剂,被显影。