Construction of the Tricyclic 5−7−6 Scaffold of Fungi-Derived Diterpenoids. Total Synthesis of (±)-Heptemerone G and an Approach to Danishefsky’s Intermediate for Guanacastepene A Synthesis
作者:Karol Michalak、Michał Michalak、Jerzy Wicha
DOI:10.1021/jo101758t
日期:2010.12.17
An efficient and operationally simple synthesis of the neodolestane diterpenoids (±)-heptemerone G and (±)-guanacastepene A is reported. The common tricyclic scaffold (±)-4 was prepared from 2-methylcyclopent-2-en-1-one via 23 isolated intermediates in 5.1% yield. The key features include a novel annulation sequence combining tandem conjugate addition, methylenation, and metathesis reaction and completely
报道了一种新的高雌烷二萜类化合物(±)-庚二酮G和(±)-胍庚二烯A的有效且操作简单的合成方法。普通的三环支架(±)-4由2-甲基环戊-2-烯-1-酮经23种分离的中间体以5.1%的收率制备。关键特征包括结合串联共轭加成,亚甲基化和易位反应的新型环空序列,以及将偶氮衍生物23完全非对映选择性转化为AB环构件32。饱和反式-azulene烯醇化物38及其α,β-不饱和对应物48的烷基化立体化学被检查了。令人惊讶的是,记录了不同的面部选择性。修改或开发了几种合成方法,包括沃顿型重排的替代方法,温和条件下可差向异构化酮的缩酮化,以及酮通过其动力学烯醇化物的有效烷基化。