Enantioselective Total Syntheses of Kuwanon X, Kuwanon Y, and Kuwanol A

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• 作者：Lei Gao ; Jianguang Han ; Xiaoguang Lei
• 刊名：Organic Letters
• 出版年：2016
• 出版时间：February 5, 2016
• 年：2016
• 卷：18
• 期：3
• 页码：360-363
• 全文大小：376K
• ISSN：1523-7052

文摘

The first enantioselective total syntheses of (?)-kuwanon X, (+)-kuwanon Y, and (+)-kuwanol A have been accomplished by using asymmetric Diels–Alder cycloaddition promoted by chiral VANOL or VAPOL/boron Lewis acid. The biosynthesis-inspired asymmetric Diels–Alder cycloaddition shows high exo selectivity (exo/endo = 13/1), which was unprecedented in the previous total syntheses of related prenylflavonoid Diels–Alder natural products. An acid catalyzed intramolecular ketalization process enabled a biomimetic transformation to construct the polycyclic skeleton of kuwanol A efficiently.