Synthesis of the C(7)–C(22) Sector of (+)-Acutiphycin via O-Directed Double Free Radical Alkyne Hydrostannation with Ph3SnH/Et3B, Double I–Sn Exchange, and Double Stille Coupling

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• 作者：Karl J. Hale ; Maciej Maczka ; Amarjit Kaur ; Soraya Manaviazar ; Mehrnoosh Ostovar ; Milosz Grabski
• 刊名：Organic Letters
• 出版年：2014
• 出版时间：February 21, 2014
• 年：2014
• 卷：16
• 期：4
• 页码：1168-1171
• 全文大小：339K
• ISSN：1523-7052

文摘

Herein a new double O-directed free radical hydrostannation reaction is reported on the structurally complex dialkyldiyne 11. Through our use of a conformation-restraining acetal to help prevent stereocenter-compromising 1,5-H-atom abstraction reactions by vinyl radical intermediates, the two vinylstannanes of 10 were concurrently constructed with high stereocontrol using Ph₃SnH/Et₃B/O₂. Distannane 10 was thereafter elaborated into the bis-vinyl iodide 9 via O-silylation and double I鈥揝n exchange; double Stille coupling of 9, O-desilylation, and oxidation thereafter furnished 8.