Efficient Stereodivergent Synthesis of <i>cis</i>-(2<i>R</i>,4<i>S</i>)-<i> </i>and <i>trans</i>-(2<i>R</i>,4<i>R</i>)-4-Phosphonomethyl-2-piperidinecarboxylic Acids from the Same Chiral Imine Derived from (<i>R</i>)-Glyceraldehyde
作者:María Díaz-de-Villegas、José Gálvez、Pablo Etayo、Ramón Badorrey
DOI:10.1055/s-2006-950272
日期:2006.10
ca. 20% overall yield starting from the easily accessible N-[(S)-1-phenylethyl]-(S)-2,3-di-O-benzylglyceraldimine. The key step for the stereodivergent synthesis is the asymmetric reduction of an exocyclic C=C double bond on a highly functionalized chiral intermediate. This intermediate is obtained by Homer-Wadsworth-Emmons (HWE) reaction of a piperidone derived from the cycloadduct obtained in the
两种非对映异构的 4-膦酰基甲基-2-哌啶-羧酸已在大约 1 中制备。从易于获得的 N-[(S)-1-苯乙基]-(S)-2,3-二-O-苄基甘油二亚胺开始,总产率为 20%。立体发散合成的关键步骤是高度官能化的手性中间体上环外 C=C 双键的不对称还原。该中间体通过哌啶酮的 Homer-Wadsworth-Emmons (HWE) 反应获得,该环加合物衍生自 N-[(S)-1-苯乙基]-(5)-2,3-之间的氮杂狄尔斯-阿尔德反应中获得的环加合物二-O-苄基甘油二亚胺和Danishefsky的二烯。在这些合成路线中,在哌啶环上产生了两个新的立体中心,具有非常好的或极好的立体选择性。