Diastereo- and Enantioselective Synthesis of Functionalized β-Lactams from Oxiranecarbaldimines and Lithium Ester Enolates
作者:Kristin Michel、Roland Fröhlich、Ernst-Ulrich Würthwein
DOI:10.1002/ejoc.200900864
日期:2009.11
The addition of nucleophiles like lithium ester enolates 6 to oxiranecarbaldimines 1 leads to new oxiranyl-functionalised β-lactams 7 in excellent enantio- and diastereoselectivity. A simple one-pot procedure affords β-lactams (azetidin-2-ones) with three or four neighbouring stereogenic centres and unlike preference. Products resulting from oxirane ring-opening reactions were not observed. An enantiomerically
将诸如锂酯烯醇化物 6 的亲核试剂添加到环氧乙烷碳二亚胺 1 中,产生了具有优异对映选择性和非对映选择性的新型环氧乙烷基官能化 β-内酰胺 7。一个简单的一锅程序提供具有三个或四个相邻立体中心的 β-内酰胺 (azetidin-2-ones),与偏好不同。没有观察到环氧乙烷开环反应产生的产物。对映体富集的例子 (2S,3S)-1g 以极好的对映体过量得到相应的 β-内酰胺 (S,S,R)-7f。根据量子化学计算,观察到的非对映选择性是过渡态亚胺双键两个面的非对映面分化的结果。(© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009)