Metal-Assisted Terpenoid Synthesis. V. The Catalytic Trimerization of Isoprene to<i>trans</i>-β-Farnesene and Its Synthetic Applications for Terpenoids
作者:Susumu Akutagawa、Takanao Taketomi、Hidenori Kumobayashi、Kiyoshi Takayama、Taichi Someya、Sei Otsuka
DOI:10.1246/bcsj.51.1158
日期:1978.4
Isoprene oligomerization was effected with a catalyst system Ni(OR)(η3-C3H5)PPh(NEt2)2 (R=n-C11H23, n-C15H31) to give a linear trimer fraction above 70% yield. The major component of the trimer fraction is (E)-7,11-dimethyl-3-methylene-1,6,10-dodecatriene (trans-β-farnesene) (1). The minor constituents of the fraction are (E)-2,6-dimethyl-10-methylene-1,6,11-dodecatriene. As slightly higher boiling
异戊二烯低聚反应用催化剂体系 Ni(OR)(η3-C3H5)PPh(NEt2)2 (R=n-C11H23,n-C15H31) 进行,得到线性三聚体部分,收率超过 70%。三聚体部分的主要成分是 (E)-7,11-二甲基-3-亚甲基-1,6,10-十二碳三烯(反式-β-法呢烯)(1)。该馏分的次要成分是 (E)-2,6-二甲基-10-亚甲基-1,6,11-十二碳三烯。作为沸点稍高的馏分,检测到两种环状三聚体 1,5,9-三甲基-1,5,9-环十二碳三烯和 1,5,10-三甲基-1,5,9-环十二碳三烯。讨论了影响通向 1 的反应路径的因素。从 1 开始合成倍半萜和二萜,包括醋酸法呢酯、法呢基丙酮和异植醇。使用钯催化剂实现 1 的区域选择性尾对尾偶联,得到二聚体 C30H48,