Planar Chirality: Cycloaddition and Transannular Reactions of Optically Active Azoninones that Contain (E)-Olefins
作者:Alexander Sudau、Winfried Münch、Jan W. Bats、Udo Nubbemeyer
DOI:10.1002/1521-3765(20010202)7:3<611::aid-chem611>3.0.co;2-9
日期:2001.2.2
Unsaturated nine-membered ring lactams that contain (E)-olefins within the ring are characterized by planar chiral properties. Thus, selective conversions of the double bond allowed a complete transfer of the planar chiral information into new stereogenic centers The basis of the transformations was the high activation barrier that prevented efficient flipping of the double bond at room temperature (epimerization
环内包含(E)-烯烃的不饱和九元环内酰胺的特征在于平面手性。因此,双键的选择性转化允许将平面手性信息完全转移到新的立体异构中心。转化的基础是高活化势垒,阻止了双键在室温下的有效翻转(均一化pR <=> pS)关于戒指。环加成在温和条件下以中等高收率选择性地非对映异构化生成环丙烷,表氨,环氧和二羟基氮杂壬酮。对环氧氮杂壬酮进行区域和非对映选择性的环戊环氧化物开环/环收缩序列,得到羟基吲哚并二酮。区域化学和立体化学结果在很大程度上取决于环氧乙烷的构型和内酰胺单元的手性信息。如此形成的具有定义的取代模式的光学活性自行车应作为生物碱合成中的通用构建基块。