De Novo Synthesis of Racemic Spirocyclopropane-Annelated 2-Deoxyhexose Derivatives
作者:Armin de Meijere、Andrei Leonov、Thomas Heiner、Mathias Noltemeyer、M. Teresa Bes
DOI:10.1002/ejoc.200390081
日期:2003.2
High-pressure-induced inverse-electron-demand hetero-Diels−Alder reactions of ethyl trans-4-ethoxy-2-oxo-3-butenoate (2a) and methyl trans-4-benzyloxy-2-oxo-3-butenoate (2b) with benzyl (cyclopropylidenemethyl) ether (1) each yielded mixtures of two separable diastereomeric esters 7a (64%) and 7b (80%) which, in three subsequent steps, led to the 3-ethylated and 3-benzylated α- and β-anomeric benzyl
反式-4-乙氧基-2-氧代-3-丁烯酸乙酯(2a)和反式-4-苄氧基-2-氧代-3-丁烯酸甲酯(2a)的高压诱导的逆电子需求杂Diels-Alder反应( 2b) 与苄基(环亚丙基甲基)醚 (1) 各自产生两种可分离的非对映体酯 7a (64%) 和 7b (80%) 的混合物,这在三个后续步骤中导致 3-乙基化和 3-苄基化的 α- 和β-异头苄基螺[2-脱氧-(D,L)-阿拉伯-吡喃己糖苷-2,1'-环丙烷]分别为α-10a,b和β-10a,b。通过 X 射线晶体结构分析证明了 β-10a 的相对构型。β-10b 的脱保护是通过 Pd 催化在二甲基乙酰胺中氢化生成螺[2-脱氧-α/β-2-(D,L)-阿拉伯-吡喃己糖苷-2,1'-环丙烷] (4) 实现的。(© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003)