underwent automatic site-selective ringopening because of the synergetic effect of the steric strain of the 1,4-epoxy moiety and the electron-donating ability of the siloxy group on the acetal structure to afford the precursors of ortho-naphthoquinone methides (o-NQMs). Subsequent Lewis acid-facilitated o-NQM formation and annulation with olefins afforded multi-fused heterocycles. Notably, the consecutive
由苯炔和呋喃生成的1-甲硅烷氧基-4-(苄氧基)甲基-1,4-环氧-1,4-二氢萘由于1,4空间张力的协同作用而自动进行位点选择性开环-环氧部分和缩醛结构上甲硅烷氧基的给电子能力,提供邻萘醌甲基化物(o -NQMs)的前体。随后路易斯酸促进邻-NQM 形成并与烯烃成环,得到多稠合杂环。值得注意的是,rubioncolin B 的连续六环骨架是通过萘并呋喃衍生物的溶剂依赖性区域选择性成环构建的。
<i>ortho</i>-Quinone Methides from <i>para</i>-Quinones: Total Synthesis of Rubioncolin B
作者:Jean-Philip Lumb、Kevin C. Choong、Dirk Trauner
DOI:10.1021/ja803498r
日期:2008.7.1
A concise synthesis of rubioncolin B is described, which features an unprecedented intramolecular Diels-Alder reaction involving an ortho-quinone methide and a naphthofuran moiety. The ortho-quinone methide is generated through a surprisingly facile tautomerization of a para-quinone.
描述了 rubioncolin B 的简明合成,其特点是前所未有的分子内 Diels-Alder 反应,涉及邻醌甲基化物和萘并呋喃部分。邻醌甲基化物是通过对醌的惊人的简单互变异构化产生的。