Asymmetric [4 + 3] Cycloadditions between Vinylcarbenoids and Dienes: Application to the Total Synthesis of the Natural Product (−)-5-epi-Vibsanin E

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• 作者：Brett D. Schwartz ; Justin R. Denton ; Yajing Lian ; Huw M. L. Davies ; Craig M. Williams
• 刊名：Journal of the American Chemical Society
• 出版年：2009
• 出版时间：June 17, 2009
• 年：2009
• 卷：131
• 期：23
• 页码：8329-8332
• 全文大小：206K
• 年卷期：v.131,no.23(June 17, 2009)
• ISSN：1520-5126

文摘

The total synthesis of (−)-5-epi-vibsanin E (2) has been achieved in 18 steps. The synthesis combines the rhodium-catalyzed [4 + 3] cycloaddition between a vinylcarbenoid and a diene to rapidly generate the tricyclic core with an effective end game strategy to introduce the remaining side-chains. The [4 + 3] cycloaddition occurs by a cyclopropanation to form a divinylcyclopropane followed by a Cope rearrangement to form a cycloheptadiene. The quaternary stereogenic center generated in the process can be obtained with high asymmetric induction when the reaction is catalyzed by the chiral dirhodium complex, Rh₂(S-PTAD)₄.