杂芳基醛的 Evans-Tishchenko 偶联。

Evans-Tishchenko coupling of heteroaryl aldehydes.

机构信息

School of Chemistry, The University of Edinburgh, West Mains Road, Edinburgh, EH9 3JJ, United Kingdom.

出版信息

J Org Chem. 2010 Nov 5;75(21):7475-8. doi: 10.1021/jo1015689.

PMID:20929205

Abstract

The low-temperature Evans-Tishchenko coupling of a range of functionalized heteroaryl aldehydes with β-hydroxy ketones in the presence of a Sm(III) catalyst has been achieved with high yields (90-99%) and good to excellent diastereoselectivity (90:10 → 95:5 dr). However, at room temperature a retro-aldol aldol-Tishchenko reaction was found to compete with the desired Evans-Tishchenko reaction. Identification of these byproducts has allowed the corresponding aldol-Tishchenko reaction to be optimized for several heteroaryl aldehydes.

摘要

在 Sm(III)催化剂的存在下，一系列功能化杂芳基醛与β-羟基酮在低温下发生 Evans-Tishchenko 偶联，产率高（90-99%），非对映选择性好至优秀（90:10→95:5 dr）。然而，在室温下，发现反-羟醛缩合-aldol-Tishchenko 反应与所需的 Evans-Tishchenko 反应竞争。通过鉴定这些副产物，使相应的 aldol-Tishchenko 反应在几种杂芳基醛的优化中成为可能。