Polyunsaturated C-Glycosidic 4-Hydroxy-2-pyrone Derivatives: Total Synthesis Shows that Putative Orevactaene Is Likely Identical with Epipyrone A
作者:Johannes Preindl、Saskia Schulthoff、Conny Wirtz、Julia Lingnau、Alois Fürstner
DOI:10.1002/anie.201702189
日期:2017.6.19
Orevactaene and epipyrone A were previously thought to comprise the same polyunsaturated tail but notably different C‐glycosylated 4‐hydroxy‐2‐pyrone head groups. Total synthesis now shows that the signature bicyclic framework assigned to orevactaene is a chimera; the compound is almost certainly identical with epipyrone A, whose previously unknown stereochemistry has also been established during this
以前认为Orevactaene和Epipyrone A包含相同的多不饱和尾巴,但C-糖基化的4-羟基-2-吡喃酮头基团则明显不同。现在,全合成表明,分配给orevactaene的标志性双环骨架是嵌合体。该化合物几乎可以肯定与Epipyrone A相同,而Epipyrone A在本研究中也已建立了以前未知的立体化学。成功的关键是通过使用钨和金催化的两个炔烃环异构化反应的序列,可以容易地形成推定的前内酯的双环核。同样重要的是,通过使用异双金属多不饱和模块获得的组装过程中的灵活性,其末端可以按照实际的一锅交叉耦合顺序进行选择性和连续处理。