Synthesis of five- to seven-membered polyfunctional terpenic carbocycles via Ti(III)-catalyzed radical cyclizations of epoxypolyprenes
作者:Alejandro F. Barrero、José F. Quílez del Moral、M. Mar Herrador、Ingrid Loayza、Elena M. Sánchez、Jesús F. Arteaga
DOI:10.1016/j.tet.2005.12.067
日期:2006.5
Ti(III)-mediated radical cyclization of monoepoxypolyprenoids can be controlled by varying the substitution pattern and/or the electronic distribution of the double bond involved in the ring closure. The feasibility of applying this idea to tandem cyclizations has also been proven. Besides, when a silyloxy function is located in α position to the oxirane ring of the acyclic polyprene, the cyclization leads to carbocyclic
Ti(III)介导的单环氧聚戊二烯基自由基环化上的环大小可通过改变取代模式和/或闭环中涉及的双键的电子分布来控制。也已经证明了将该想法应用于串联环化的可行性。此外,当甲硅烷氧基官能团位于无环聚戊二烯的环氧乙烷环的α位时,环化导致在A环中双官能化的碳环萜烯类化合物以可接受的收率。这些结果大大拓宽了该方法的范围。