Synthesis of the Tetracyclic ABCD Ring Domain of Calyciphylline A-Type Alkaloids via Reductive Radical Cyclizations

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• 作者：Guilhem Coussanes ; Josep Bonjoch
• 刊名：Organic Letters
• 出版年：2017
• 出版时间：February 17, 2017
• 年：2017
• 卷：19
• 期：4
• 页码：878-881
• 全文大小：447K
• ISSN：1523-7052

文摘

A tetracyclic compound with the ABCD ring framework of calyciphylline A-type alkaloids was synthesized from a cis-3a-methyloctahydroindole triggered by a 5-endo radical cyclization. The synthesis required two additional ring-forming steps: the construction of a seven-membered ring by aldol cyclization and the azabicyclic fragment by a radical ring closure of a trichloroacetamide-tethered enol acetate followed by a diastereoselective α-methylation of the lactam group.