The stereoselective construction of the CDEFGH ring system of lancifodilactone G is described. The key steps in this synthesis are (i) ring-closing metathesis for formation of the oxa-bridged eight-membered ring; (ii) an intramolecular Pauson–Khand reaction for construction of the sterically congested F ring; and (iii) sequential cross-metathesis, hydrogenation, and lactonization reactions for installation of the anomerically stabilized bis-spiro ketal fragment of lancifodilactone G.

中文翻译：

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Lancifodilactone G Acetate的不对称全合成。1. CDEFGH环系统的非对映选择性合成

描述了lancifodilactone G的CDEFGH环系统的立体选择性结构。该合成的关键步骤是：（i）形成氧杂桥联的八元环的闭环易位；（ii）分子内的Pauson-Khand反应，用于构建空间拥挤的F环；（iii）顺序的交叉复分解，氢化和内酯化反应，以安装Lancifodilactone G的异源稳定的双螺缩酮片段。