(±)-Kelsoene (1) has been synthesized in 15 steps from commercially available cyclopent-2-en-1-one. Key steps include (a) a methylenecyclopentane annulation of cyclopent-2-en-1-one using the bifunctional cuprate reagent lithium cyano(4-chlorobut-1-en-2-yl)cuprate and (b) a highly stereoselective [2+2]-photocycloaddition of ethylene to the bicyclic enone 10.
(±)-Kelsoene (1) 由市售的环戊-2-en-1-酮经过 15 个步骤合成。关键步骤包括 (a) 使用双功能
铜酸盐试剂
氰基(4-
氯丁-1-en-2-基)
铜酸
锂对环戊-2-en-1-酮进行
亚甲基环戊烷环化,以及 (b) 高度立体选择性的 [2+ 2]-
乙烯与双环烯酮 10 的光环加成反应。