钯催化由2-溴-1,3,5-三烯通过亚烷基-π-烯丙基钯介导的形式SN2" 途径制备乙烯基联烯。

Palladium-catalyzed preparation of vinylallenes from 2-bromo-1,3,5-trienes via an alkylidene-pi-allylpalladium-mediated formal SN2" pathway.

作者信息

Ogasawara Masamichi, Fan Liyan, Ge Yonghui, Takahashi Tamotsu

机构信息

Catalysis Research Center and Graduate School of Pharmaceutical Sciences, Hokkaido University and SORST, Japan Science and Technology Agency (JST), Kita-ku, Sapporo 001-0021, Japan.

出版信息

Org Lett. 2006 Nov 9;8(23):5409-12. doi: 10.1021/ol062309e.

DOI:10.1021/ol062309e

PMID:17078730

Abstract

[Structure: see text] A novel Pd-catalyzed reaction to prepare conjugated vinylallenes from 2-bromo-1,3,5-triene and a soft nucleophile via a formal SN2" pathway was developed. The reaction proceeds via alkylidene-pi-allylpalladium and allenyl-pi-allylpalladium intermediates, and a dynamic process involving the two palladium intermediates played important roles in determining the selectivity of the Pd-catalyzed reaction. The reaction was extended to an asymmetric counterpart, and an axially chiral vinylallene was obtained with up to 81% ee.

摘要

[结构：见正文] 开发了一种新颖的钯催化反应，通过形式上的SN2”途径，由2-溴-1,3,5-三烯和软亲核试剂制备共轭乙烯基丙二烯。该反应通过亚烷基-π-烯丙基钯和烯丙基-π-烯丙基钯中间体进行，涉及这两种钯中间体的动态过程在决定钯催化反应的选择性方面起着重要作用。该反应扩展到不对称反应，得到了对映体过量高达81%的轴手性乙烯基丙二烯。