Highly Regio- and Stereoselective Cyclic Iodoetherification of 4,5-Alkadienols. An Efficient Preparation of 2-(1′(Z)-Iodoalkenyl)tetrahydrofurans

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• 作者：Bo Lü ; Xinpeng Jiang ; Chunling Fu ; Shengming Ma
• 刊名：Journal of Organic Chemistry
• 出版年：2009
• 出版时间：January 2, 2009
• 年：2009
• 卷：74
• 期：1
• 页码：438-441
• 全文大小：208K
• 年卷期：v.74,no.1(January 2, 2009)
• ISSN：1520-6904

文摘

In this paper, an efficient way to synthesize 2-(1′(Z)-iodoalkenyl)tetrahydrofurans from 4,5-alkadienols and I₂ was developed. The reaction of the 4,5-allenols with a substituent in the 3-position afforded the trans-2,3-disubstituted tetrahydrofurans with very high diastereoselectivity. However, when the axially optically active 4,5-allenol was treated with I₂ in n-hexane, the efficiency for chirality transfer was low. This problem was circumvented by conducting the reaction in CH₂Cl₂ at room temperature and applying N-iodosuccinimide as the electrophilic reagent; however, the Z/E ratio for the products is much lower. Highly optically active Z-products may be prepared via the kinetic resolution via a Sonogashira coupling reaction with propargyl alcohol.