Acid catalyzed ring contractions in endo-2,8-trimethylene-cis-bicyclo[3.3.0]octyl cations to methylperhydrotriquinacenes. One of the methyl ext
作者:Yoshiaki Fujikura、Naotake Takaishi、Yoshiaki Inamoto
DOI:10.1016/0040-4020(81)80014-2
日期:——
Sulfuric acid catalyzed ring contractions with extrusion of a methyl group were examined for alcohol and olefin derivatives (28–31) of endo-2,8-trimethylene-cis-bicyclo[3.3.0]octane (11), which was one of the two possible progenitors, among altogether 69 isomers, for methylperhydrotriquinacenes (6, 7 and 12), the only methyltricyclodecane intermediates found so far, in the tricycloundecane rearrangement
催化环收缩用甲基的挤出硫酸检查醇和烯烃衍生物(28 - 31)的内切-2,8-三亚甲基顺-二环[3.3.0]辛烷(11),这是的一个在总共69个异构体中,有两个可能的祖先是甲基全氢三喹并烷(6、7和12),这是迄今为止在三环十一烷重排中唯一的甲基三环癸烷中间体。这些反应物仅形成了少量(1.6–2.0%)的甲基全氢三苯并二氢呋喃28-31,结果支持了较早的理论结论,即甲基挤出在能量上通常是非常不利的过程,这是由于形成了初级羧甲基阳离子,而以更稳定的仲桥或叔桥头为代价。这些前体的反应途径28 - 31用参考那些perhydrotriquinacene 2- carbinyl阳离子(对所讨论33A的),这对应于某些所述环收缩产物的阳离子的从28 - 31。