醛的偕烯丙基硼化和偕 crotylboration。

Homoallylboration and homocrotylboration of aldehydes.

机构信息

Department of Chemistry MS 015, Brandeis University, Waltham, Massachusetts 02454-9110, USA.

出版信息

J Am Chem Soc. 2011 Nov 23;133(46):18514-7. doi: 10.1021/ja2048682. Epub 2011 Oct 27.

DOI:10.1021/ja2048682

PMID:22014243

Abstract

A simple method for addition of homoallylic fragments to aldehydes is described. Cyclopropanated allylboration reagents react with aldehydes in the presence of PhBCl(2) to give high yields of bishomoallyl alcohols. Cyclopropanated cis- and trans-crotyl reagents afford the corresponding 1,3-anti- and 1,3-syn-methyl-substituted "homocrotylated" alcohols with high selectivity, consistent with a Zimmerman-Traxler transition state. Accordingly, the optically active α-substituted reactant affords the E-substituted product in 97:3 er.

摘要

描述了一种向醛中添加偕丙基片段的简单方法。在 PhBCl(2) 的存在下，环丙基烯丙基硼试剂与醛反应，以高收率得到双偕丙基醇。环丙基顺式和反式 -2-丁烯基试剂以高选择性提供相应的 1,3-反式和 1,3-顺式 - 甲基取代的“偕丁烯基化”醇，与 Zimmerman-Traxler 过渡态一致。因此，光学活性的 α-取代反应物以 97:3 的对映选择性得到 E-取代产物。