期刊
TETRAHEDRON
卷 75, 期 31, 页码 4110-4117出版社
PERGAMON-ELSEVIER SCIENCE LTD
DOI: 10.1016/j.tet.2019.04.019
关键词
Asymmetric allylboration; A(1,2) allylic strain; syn-pentane interaction
资金
- Auburn University
Enantioselective allylboration of aldehydes with alpha-substituted beta-methyl allylboronate was reported. By using BF3 center dot OEt2 as the catalyst, gamma,delta-disubstituted homoallylic alcohols were obtained in good yields with high E-selectivities and enantioselectivities. Transition state analysis revealed that the disfavored transition state suffers from a syn-pentane interaction between the BF3 catalyst and axially oriented alpha-substituent of the allylboron reagent. Such a syn-pentane interaction is severe enough to overcome the A(1,2) allylic strain between the beta-methyl group and the alpha-substituent of the boron reagent that is present in the favored competing transition state. Consequently, the reaction proceeded with equatorial placement of the alpha-substituent to furnish gamma-methyl substituted homoallylic alcohols with high E-selectivity. Published by Elsevier Ltd.
作者
我是这篇论文的作者
点击您的名字以认领此论文并将其添加到您的个人资料中。
推荐
暂无数据