Lanthanoid(III) Trichloride–Tin(II) Chloride Mediated Cydoaddition Reaction of α,α′-Dibromo Ketones with 1,3-Dienes or Enamines
作者:Shin-ichi Fukuzawa、Masakazu Fukushima、Tatsuo Fujinami、Shizuyoshi Sakai
DOI:10.1246/bcsj.62.2348
日期:1989.7
ketones with 1,3-dienes in the presence of CeCl3–SnCl2 in tetrahydrofuran is found to give the corresponding [3+4] cycloadduct in fair to good yields under mild conditions. Furan and cyclopentadiene serve as highly efficient receptors of the oxyallyl intermediate to give bicyclic cycloadducts. The reaction of 2,4-dibromo-3-pentanone with isoprene gives both [3+4] and [3+2] cycloadducts. [3+2] Cycloaddition
α,α'-二溴酮与 1,3-二烯在 CeCl3-SnCl2 存在下在四氢呋喃中的反应被发现在温和条件下以相当到良好的产率得到相应的 [3+4] 环加合物。呋喃和环戊二烯作为氧烯丙基中间体的高效受体,产生双环环加合物。2,4-二溴-3-戊酮与异戊二烯反应生成[3+4] 和[3+2] 环加合物。[3+2] 环加成与烯胺类似,在用 3% NaOH 乙醇溶液处理后得到 2-环戊烯-1-酮。