Reactions of Carbanions of 1-Chloro-5-(phenylsulfonyl)pent-2-enes: Synthesis of Vinyl-Substituted Tetrahydrofurans
作者:Anna Wojtasiewicz、Bartosz Lewandowski、Marek Judka、Mieczysław Mąkosza
DOI:10.1002/ejoc.200900275
日期:2009.8
The carbanions of (E)- and (Z)-1-chloro-5-(phenylsulfonyl)-pent-2-enes can be considered as vinylogues of γ-chlorocarbanions. Because in these cases intramolecular 1,3-substitution by a SN2′ mechanism leading to vinylcyclopropanes is a relatively slow process these carbanions can be efficiently trapped by active electrophilic reagents such as aldehydes. Subsequent intramolecular SN2′ 1,5-substitution
(E)- 和 (Z)-1-chloro-5-(phenylsulfonyl)-pent-2-enes 的碳负离子可以被认为是 γ-氯碳负离子的乙烯系。因为在这些情况下,SN2' 机制的分子内 1,3-取代导致乙烯基环丙烷是一个相对缓慢的过程,这些碳负离子可以被活性亲电试剂(如醛)有效捕获。随后产生的羟醛阴离子的分子内 SN2' 1,5-取代得到乙烯基取代的四氢呋喃。因此,已经详细阐述了一种合成 2,3-二取代-5-乙烯基四氢呋喃的有效方法。(© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009)