The Carbohydrate−Sesquiterpene Interface. Directed Synthetic Routes to Both (+)- and (−)-Fomannosin from <scp>d</scp>-Glucose
作者:Leo A. Paquette、Xiaowen Peng、Jiong Yang、Ho-Jung Kang
DOI:10.1021/jo8004233
日期:2008.6.1
An enantiodivergent strategy for the total chemical synthesis of both naturally occurring (+)-fomannosin (1) and its (−)-antipode (ent-1) from α-d-glucose has been developed and successfully implemented. The key steps in the overall pathway include the following: (i) application of the zirconocene-mediated ring contraction of vinyl furanosides for the construction of highly substituted cyclobutanols;
已开发并成功实施了一种自然化学(+)-fomannosin(1)及其从α- d-葡萄糖合成其(-)-antipode(ent - 1)的化学合成对映体策略。总体途径中的关键步骤包括:(i)锆茂茂介导的乙烯基呋喃糖苷的环收缩在构建高度取代的环丁醇中的应用;(ii)利用闭环复分解反应形成五元侧链。(iii)求助于单硫代丙二酸酯,以将其化学选择性还原成敏感的内酯中间体45;(iv)用OsO 4进行羟基定向的二羟基化反应,生成48; (v)通过环亚硫酸盐和三氟甲磺酸环丁酯顺序消除。对映体系列之间的桥由六步连接组成,涉及22的结构修饰以产生ent - 30b。光学活性在整个过程中被完全保留。