Application of the Anionic Oxy-Cope Rearrangement to Stereocontrolled Synthesis of the A/B Subunit of Cytoxic 8,9-Seco-<i>ent</i>-kaurenes
作者:Gaétan Ladouceur、Leo A. Paquette
DOI:10.1055/s-1992-34185
日期:——
Methodology is described for expedient synthesis of the A/B framework of 8,9-seco-ent-kaurenes and for introduction of the 5-methylene-2-cyclopentenone moiety. In the first part of the study, a sequence of only six steps is necessary to convert 2-(hydroxymethylene) cyclohexanone to a key functionalized intermediate. Five of the transformations are 100% stereocontrolled as a direct result of complementary steric biases that operate in the desired direction. The final target is arrived at by selective protection/oxidation of the oxygenated centers. This first synthetic entry to the structural core of the titled diterpenes is expected to guide the future de novo acquisition of these cytotoxic agents.
本文描述了8,9-seco-ent-kaurenes的A/B框架的快速合成方法,以及5-亚甲基-2-环戊烯酮部分的引入方法。在研究的第一部分,只需要六个步骤就可以将2-羟基亚甲基环己酮转化为关键的官能化中间体。其中五个转化是100%立体控制的,这是互补空间位阻作用在所需方向上直接作用的结果。通过选择性保护/氧化含氧中心,最终达到目标。这是首次合成进入标题所述二萜类化合物结构核心的方法,有望指导未来这些细胞毒性药物的从头合成。