This paper describes the totalsyntheses of spirooliganones A and B, which provides control over the stereochemistry of the spiro center via a cascade reaction involving the in situ formation of an o-quinone methide and a hetero-Diels–Alder reaction.
本文描述了螺寡糖 A 和 B 的全合成,通过涉及邻醌甲基化物的原位形成和杂-Diels-Alder 反应的级联反应控制螺中心的立体化学。
Total Syntheses of (−)-Spirooliganones A and B
作者:Lin Wei、Mingxing Xiao、Zhixiang Xie
DOI:10.1021/ol501050s
日期:2014.5.16
The enantioselective syntheses of (−)-spirooliganones A and B have been accomplished in eight steps from commercially available starting materials. Noteworthy transformations include a three-component hetero-Diels–Alder cycloaddition to construct the tetracyclic core of spirooliganones, a Sharpless asymmetric dihydroxylation, and a tandem oxidative dearomatization/cyclization to build the oxa-spiro
Two novel spirooliganones A (1) and (2), a pair of Spiro carbon epimers, with a rare dioxaspiro skeleton were isolated from the roots of illicium oligandrum. The structures were fully determined by spectroscopic analysis and chemical methods, especially modified Mosher's method, and X-ray diffraction analysis. Spirooliganone B was found to exhibit more potent activities against coxsackie virus B3 and influenza virus A (H3N2) (IC50 3.70-5.05 mu M) than spirooliganone A. The biosynthetic pathway involving a hetero-Diels-Alder reaction of the epimers was proposed.