Stereoselective C-Glycosidations with Achiral and Enantioenriched Allenylsilanes

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• 作者：Ryan A. Brawn ; James S. Panek
• 刊名：Organic Letters
• 出版年：2010
• 出版时间：October 15, 2010
• 年：2010
• 卷：12
• 期：20
• 页码：4624-4627
• 全文大小：180K
• 年卷期：v.12,no.20(October 15, 2010)
• ISSN：1523-7052

文摘

Allenylsilanes are used as carbon nucleophiles in highly stereoselective Lewis acid-promoted C-glycosidations, resulting in the introduction of an internal alkyne with an adjacent stereocenter. Both achiral and chiral allenylsilanes form the desired products with high diastereoselectivity, where the nucleophile adds exclusively to the α-face of the intermediate oxonium ion. Reactions with glucal and galactal afford dihydropyran products, while reactions with a ribose derivative yield dihydrofuran products.