Enantio- and Diastereoselective Synthesis of Highly Substituted Acylcyclopropanes from Homoaldol Products by Stereospecific Homoallylic Cyclization
作者:Rainer Kalkofen、Sven Brandau、Seda Ünaldi、Roland Fröhlich、Dieter Hoppe
DOI:10.1002/ejoc.200500283
日期:2005.11
Highly enantioenriched 4-hydroxy-1-alkenyl N,N-diisopropylcarbamates, easily available by asymmetric homoaldol reaction, cyclize by treatment with sodium hydride to form (1r,2t,3t)-configured 1-acylcyclopropanes with high diastereoselectivity. The decisive steps are the migration of the N,N-diisopropylcarbamoyl group onto the alkoxide oxygen atom, followed by an intramolecular homoallylic substitution
高度对映体富集的 4-羟基-1-烯基 N,N-二异丙基氨基甲酸酯,可通过不对称高醛醇反应轻松获得,通过用氢化钠处理环化形成具有高非对映选择性的 (1r,2t,3t)-构型 1-酰基环丙烷。决定性的步骤是 N,N-二异丙基氨基甲酰基迁移到醇盐氧原子上,然后是中间体 γ-氨基甲酰氧基烯醇化物的分子内均烯丙基取代反应,γ-C 原子的构型发生反转。(© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005)