Lewis酸与碳水化合物骨架参与的高非对映选择性5-己烯基自由基环化反应。

Highly diastereoselective 5-hexenyl radical cyclizations with Lewis acids and carbohydrate scaffolds.

作者信息

Enholm E J, Cottone J S, Allais F

机构信息

Department of Chemistry, University of Florida, Gainesville, Florida 32611, USA.

出版信息

Org Lett. 2001 Jan 25;3(2):145-7. doi: 10.1021/ol006651h.

DOI:10.1021/ol006651h

PMID:11430020

Abstract

[figure: see text] Carbohydrates as removable chiral scaffolds for free radical cyclizations were examined for the first time. This investigation illustrates the utility of two inexpensive carbohydrate derivatives as sources of asymmetry for 5-hexenyl radical cyclizations. Diastereomeric ratios as high as 100:1 were achieved with an ester-appended (+)-isosorbide hexose and 70:1 for a diol-protected D-xylose pentose. Temperature dependence, Lewis acids, and solvents were all examined. By correlation with known compounds, the newly generated chiral centers were of the (S)-configuration.

摘要

[图：见正文]首次研究了碳水化合物作为用于自由基环化反应的可去除手性支架。该研究表明了两种廉价的碳水化合物衍生物作为5-己烯基自由基环化反应不对称源的实用性。对于带有酯基的(+)-异山梨醇己糖，非对映体比例高达100:1，对于二醇保护的D-木糖戊糖，该比例为70:1。研究了温度依赖性、路易斯酸和溶剂。通过与已知化合物的相关性分析，新生成的手性中心为(S)-构型。