Diastereoselective synthesis of d-xylo-isoxazolidinyl nucleosides
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- 作者：Eva Hý ; roš ; ová ; Michal Medvecký ; Lubor Fiš ; era ; Christian Hametner ; Johannes Frö ; hlich ; Martina Marchetti ; Gü ; nter Allmaier
- 关键词：Nucleosides ; 1 ; 3-Dipolar cycloaddition ; C-Glycosyl nitrones
- 刊名：Tetrahedron
- 出版年：2008
- 出版时间：31 March 2008
- 年：2008
- 卷：64
- 期：14
- 页码：3111-3118
- 全文大小：327 K
文摘
The condensation of the acetoxyisoxazolidines with silylated uracil, thymine, cytosine, N-acetylcytosine, and guanine proceeded in good yields and with moderate to good stereoselectivity to give isoxazolidinyl β- and α-nucleosides. The stereoselectivity of the addition is dependent on the structure of the substituent at C-3 originating from the starting chiral nitrone. The Vorbrüggen nucleosidation of isoxazolidine 8 at 70 °C afforded β-anomers as the exclusive nucleosides together with the isoxazoline 11. It was found that the nucleosidation proceeded also in methylene chloride at room temperature.