Chiral amine-induced stereoselectivity in trans-β-lactam formation via Staudinger cycloaddition
作者:Aleksandar R. Todorov、Vanya B. Kurteva、Ranko P. Bontchev、Nikolay G. Vassilev
DOI:10.1016/j.tet.2009.10.063
日期:2009.12
series of chiral trans-β-lactams was obtained via Staudinger cycloaddition with low to moderate diastereoselectivity (up to 54% de) induced by a chiral amine component of the imine. It was shown that the direct connection of nitrogen to a chiral centre is crucial to induce chirality; moderate asymmetric induction was achieved by using isomeric 1-phenylethylamines, which are among the cheapest chiral sources
通过Staudinger环加成反应获得了一系列低至中等非对映选择性的手性反式-β-内酰胺(高达54%de)由亚胺的手性胺成分诱导。结果表明,氮与手性中心的直接连接对于诱导手性至关重要。通过使用异构的1-苯基乙胺可实现中等程度的不对称诱导,该异构体是市场上最便宜的手性来源之一,而3-氨基甲基pin烷则具有较低的非对映选择性,其中手性中心与亚甲基之间的氮原子距离较远。结果表明,将反应温度从110°C升高到140°C可获得相称的结果,但显着加快了转化速度。苯乙胺衍生物的绝对构型是通过对选定样品进行X射线分析确定的。