Intermolecular Diels–Alder Cycloaddition for the Construction of Bicyclo[2.2.2]diazaoctane Structures: Formal Synthesis of Brevianamide B and Premalbrancheamide

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• 作者：Jacob G. Robins ; Kyu J. Kim ; Alex J. Chinn ; John S. Woo ; Jonathan R. Scheerer
• 刊名：Journal of Organic Chemistry
• 出版年：2016
• 出版时间：March 18, 2016
• 年：2016
• 卷：81
• 期：6
• 页码：2293-2301
• 全文大小：690K
• ISSN：1520-6904

文摘

A stereoselective intermolecular Diels–Alder cycloaddition of an intermediate pyrazinone with both achiral and chiral acrylate-derived dienophiles provides rapid access to the bicyclo[2.2.2]diazaoctane core shared among several prenylated indole alkaloids. The product derived from cycloaddition with 2-nitroacrylate required an additional five to six synthetic operations to intercept established precursors to premalbrancheamide and brevianamide B. The chemistry detailed in this manuscript constitutes a formal total synthesis (12 steps each) of these [2.2.2]diazabicyclic natural products from proline methyl ester.