Department of Chemistry, University of Alberta, E3-43 Gunning-Lemieux Chemistry Centre, Edmonton, AB T6G 2G2, Canada.
Org Lett. 2011 Feb 18;13(4):720-3. doi: 10.1021/ol102953s. Epub 2011 Jan 11.
A short, stereoselective approach to the fused tricyclic carbon skeleton found in the tigliane and daphnane classes of diterpene natural products is described. Convergent coupling of the A- and C-rings, followed by diastereoselective cerium enolate addition and formation of a double acetal set the stage for generation of an oxonium ylide via a transient metallocarbene. An efficient Stevens [1,2]-shift furnished the 7-membered B-ring, possessing the bridgehead oxygenation pattern found in the natural systems.
描述了一种短的、立体选择性的方法，用于构建在二萜天然产物的紫杉烷和瑞香烷类中发现的稠合三环碳骨架。A-和 C-环的会聚偶联，接着是立体选择性的铈烯醇化物加成和双缩醛的形成，为通过瞬态金属卡宾生成氧翁叶立德奠定了基础。有效的史蒂文斯[1,2]-迁移提供了具有天然体系中桥氧取代模式的 7 元 B-环。
