First Asymmetric Synthesis of (+)-Sordidin and (-)-7-epi-Sordidin, Aggregation Pheromones of the Banana WeevilCosmopolites sordidus
作者:Dieter Enders、Irene Breuer、Anja Nühring
DOI:10.1002/ejoc.200500112
日期:2005.7
The asymmetric synthesis of (1S,3R,5R,7S)-(+)-sordidin and 7-epi-(1S,3R,5R,7R)-(–)-sordidin, both components of the natural male-produced aggregation pheromone of the banana weevil Cosmopolites sordidus (Germar), starting from 2,2-dimethyl-1,3-dioxan-5-one is described. Two of the stereogenic centers were generated by three α-alkylations of the corresponding RAMP-hydrazone. Diastereoselective epoxide
(1S,3R,5R,7S)-(+)-sordidin 和 7-epi-(1S,3R,5R,7R)-(-)-sordidin 的不对称合成,这两种天然雄性聚集信息素的成分描述了从 2,2-二甲基-1,3-二恶烷-5-one 开始的香蕉象鼻虫 Cosmopolites sordidus (Germar)。两个立体中心由相应的 RAMP-腙的三个 α-烷基化产生。非对映选择性环氧化物开放是合成的另一个关键步骤,使用 3-戊酮 SAEP-腙的氮杂烯醇化物作为亲核试剂,随后的酸性分子内缩醛化以良好的总产率 (39%) 提供了 sordidin C-7 差向异构体,为 1.5:1 非对映异构体混合物。差向异构体可以通过制备型 GC 进行分离,因此,它们中的每一个都可以获得高非对映体和对映体纯度(de ≥ 97 %,ee ≥ 98 %)。