Synthetic Studies on Dicyclopenta[a,d]cyclooctane Terpenoids: Construction of the Core Structure of Fusicoccins and Ophiobolins on the Route Involving a Wagner-Meerwein Rearrangement
作者:Michał Michalak、Karol Michalak、Zofia Urbanczyk-Lipkowska、Jerzy Wicha
DOI:10.1021/jo201357p
日期:2011.9.16
The total diastereoselective synthesis of dicyclopenta[a,d]cyclooctane core skeleton of tricyclic terpenoids, fusicoccins, and ophiobolins is reported. The synthesis commences from 2-methylcyclopent-2-en-1-one and leads first to the easily accessible intermediary cyclopenta[8]annulene 18. The subsequent steps include two key transformations: shifting the angular methyl group from the angular to the
据报道,总的非对映选择性合成三环萜类化合物,岩藻球菌素和ophiobolins的双环戊[a,d]环辛烷核心骨架。合成过程从2-甲基环戊-2-烯-1-酮开始,并首先导致容易获得的中间环戊[8]环戊烯18。随后的步骤包括两个关键的转换:使用碳阳离子重排(26 → 28)将角甲基从角位置移到相邻位置,以及通过α-甲基环辛酮中间体的烷基化(38 → 48)来构建季立体中心。)。在后一种转化的背景下,进行了一系列关于2-甲基环辛-1-酮烷基化的模型实验。通过对关键结构39和50的X射线分析来验证立体化学分配。