作者:C. J. Devlin、Brian J. Walker
DOI:10.1039/p19720001249
日期:——
The stereochemistry of dehalogenation reactions with triphenylphosphine (a two-electron dehalogenating reagent) has been investigated. Both eythro-(or meso-) and threo-[or (±)-] dibromides give entirely trans-olefin, except for (±)-stilbene dibromide which gave a 36 : 65 cis–trans-mixture (the olefins formed were identified by n.m.r. spectroscopy). Authentic samples of cis-olefin in each case were shown
已经研究了与三苯膦(一种双电子脱卤剂)进行脱卤反应的立体化学。既eythro - (或内消旋- )和苏式- [或(±) - ]二溴化物得到完全的反式烯烃,除了(±) -芪这给了一个36二溴化物:65个顺式-反式-混合物(所形成的被确定的烯烃通过核磁共振光谱)。在每种情况下,真实的顺式烯烃样品均不会与反式异构化在反应条件下生成。根据膦对卤素的初始攻击,简要给出了脱卤的机理,从而给出了一个中间离子对。1,2-二溴-2-硝基苯乙烯与三苯基膦在甲醇中的反应可得到证据,得到2-硝基-1-苯基乙基三苯基溴化phosph。与赤型-2,3-二溴丁酸发生脱卤代氢反应而不是脱溴反应,得到α-溴巴豆酸和α-溴异巴豆酸的混合物。试图将脱卤反应扩展到三元和六元环的形成的尝试是不成功的。