Diastereoselectivity of Chiral Nitrone 1,3-Dipolar Cycloaddition to Baylis-Hillman Adducts

被引：0

作者：

Branislav Dugovič

Lubor Fišera

Christian Hametner

Michał K. Cyrański

Nada Prónayová

机构：

[1] Slovak University of Technology,Department of Organic Chemistry

[2] Institute of Applied Synthetic Chemistry,Department of Chemistry

[3] Vienna University of Technology,undefined

[4] University of Warsaw,undefined

[5] Central Laboratory of Chemical Techniques,undefined

[6] Slovak University of Technology,undefined

来源：

Monatshefte für Chemie / Chemical Monthly | 2004年 / 135卷

关键词：

Keywords. Dipolar cycloaddition; Stereoselectivity; Nitrones; Isoxazolidines; Microwave heating.;

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摘要：

1,3-Dipolar cycloadditions of chiral nitrones to Baylis-Hillman adducts (β-hydroxy-α-methylene esters) proceed with complete regioselectivity in good yields to afford the corresponding diastereomeric 3,5,5-trisubstituted isoxazolidines. Attack of the dipole from the less sterically hindered side of the dipolarophiles affords C-3/C-5 cis isoxazolidines as the predominant isomers. The strong preference for the C-3/C-5 cis isoxazolidines provided more sterically demanding O-tert-butyldimethylsilylsubstituted nitrone 2. Addition of Lewis acids accelerates the reaction and increases the portion of C-3/C-5 trans isoxazolidines. Microwave irradiation accelerates the reaction, but it produces only a small effect on the diastereoisomeric product ratio.

引用

页码：685 / 696

页数：11