Peri-Selective Cycloaddition Reactions of 3-Methoxycarbonyl-2<i>H</i>- cyclohepta[<i>b</i>]furan-2-one with 6,6-Dimethylfulvene
作者:Masafumi Yasunami、Yoichiro Kitamori、Ikue Kikuchi、Hajime Ohmi、Kahei Takase
DOI:10.1246/bcsj.65.2127
日期:1992.8
changed to the [8+2] cycloadduct under refluxing in xylene by a retro–Diels–Alder reaction, a re-cycloaddition reaction followed by spontaneous decarboxylation. The structure of the [8+2] cycloadduct was clearly confirmed by chemical transformation to methyl 3-isopropyl-1H-cyclopent[a]azulene-9-carboxylate which was obtained by the hydride reduction of methyl 3-isopropylidene-3H-cyclopent[a]azulene-9-carboxylate
3-甲氧基羰基-2H-环庚基[b]呋喃-2-酮与6,6-二甲基富烯的环加成反应在乙醇、苯或二甲苯中回流下进行。[4+2] 环加合物作为乙醇或苯中的主要产物与次要的 [8+2] 环加合物一起形成。另一方面,[8+2] 环加合物在二甲苯中作为单一产物形成。[4+2] 环加合物在二甲苯中通过逆-狄尔斯-阿尔德反应回流下完全变成 [8+2] 环加合物,再环加成反应随后自发脱羧。[8+2]环加合物的结构通过化学转化为3-异丙基-1H-环戊[a]azulene-9-羧酸甲酯的化学转化而得到明确证实,该甲基3-异丙基-1H-环戊[a]azulene-9-carboxylate由甲基3-isopropidene-3H-cyclopent[a]的氢化物还原得到。 a]azulene-9-carboxylate。