ORGN 462 |
| We describe a novel application of the gold-catalyzed cycloisomerization of ynals bearing a pendant unsaturated bond to total synthesis of faveline. Faveline is a tricyclic diterpene containing a central cycloheptane ring known to lower blood pressure in mice. Synthesis of faveline was initiated with syntheses of two fragments 5 and 8. Sonogashira coupling between 5 and 8 smoothly gave the enynal 9 in multi-gram scale. With our previously reported Au-catalyzed method, we could accomplish cycloisomerization of diynal 9 to the tricyclic compound 10. Final demethylation with Lewis acid furnished faveline in only seven steps. In conclusion, we discovered a new Au-catalyzed cycloisomerization of diynals and enynals leading to synthetically valuable [6,7,n] tricyclic compounds, and successfully applied to the total synthesis of faveline. We wish to acknowledge the financial support by Center for Molecular Design and Synthesis (CMDS) and BK21.
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Modern Acetylene Chemistry
8:00 PM-10:00 PM, Tuesday, 12 September 2006 Moscone Center -- Hall D, Poster
Division of Organic Chemistry |
