The Wittig reaction: comments on the mechanism and application as a tool in the synthesis of conjugated dienes
作者:Rut Ideses、Arnon Shani
DOI:10.1016/s0040-4020(01)81031-0
日期:1989.1
Wittig reaction, of conjugated dienes with specific stereochemistry (either or ) at the newly formed double bond, without isomerization of the existing (“old”) double bond, it is better to react a reactive (nonstabilized) saturated ylide with an α, β-unsaturated aldehyde. The opposite approach, namely, the reaction of a moderate (semi-stabilized) allylic ylide with a saturated aldehyde produces a mixture
对于通过新的双键具有特定立体化学(或)的共轭二烯进行Wittig反应,在不使现有(“旧”)双键异构化的情况下,最好使反应性(不稳定的)饱和内立德反应与一个α,β-不饱和醛。相反的方法,即中度(半稳定)的烯丙基内酯与饱和醛的反应产生了几何异构体的混合物,这是由于增加了产物的产量。-在新的双键处的构型,和现有双键的显着异构化。拟议的中间体甜菜碱结构只能解释Li反应的两个当量。在其他反应中,不稳定的赤型-氧杂磷杂环戊烷可能是中间体,它是由叶立德和羰基形成早期的抗或GaucheCC键生成的,然后从中形成Z-双键。