作者:Dennis P. Curran、Shen-Chun Kuo
DOI:10.1016/s0040-4020(01)87744-9
日期:1987.1
Models studies and the total synthesis ofsilphiperfol-6-ene (4, seven steps) and 9-episilphiperfol-6-ene (14, five steps) are reported. The use of a tandem radical cyclization permits rapid construction of the requisite tricyclic nucleus. In the most direct approach, the key tandem cyclization (18 → 19) produces the C-9 epimer as the major product. In a modified approach, cyclization of the dioxolane
报道了模型研究和silphiperfol-6-ene(4个,七个步骤)和9-epilsilphiperfol-6-ene(14个,五个步骤)的总合成。串联自由基环化的使用允许快速构建必需的三环核。在最直接的方法中,关键的串联环化反应(18 → 19)将C-9差向异构体作为主要产物。在一种改进的方法中,衍生自18(27 → 28)的二氧戊环缩酮的环化产生有用的过量的天然异构体。关于乙烯基硅烷快速质子异构化为烯丙基硅烷的有趣观察(21 → 22 + 23)也进行了讨论。