125.Asymmetric Total Synthesis of Lancifodilactone G Acetate. 1. Diastereoselective Synthesis of CDEFGH Ring System

Tian-Wen Sun, Dong-Dong Liu, Kuang-Yu Wang, Bing-Qi Tong, Jia-Xin Xie, Yan-Long Jiang, Yong Li, Bo Zhang, Yi-Fan Liu, Yuan-Xian Wang, Jia-Jun Zhang, Jia-Hua Chen*, Zhen Yang*

J. Org. Chem., 2018, 83 (13), 6893–6906

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.