Mechanism of base catalysis in the reactions of phenyl aryl ethers with aliphatic amines in dimethyl sulfoxide
作者:Rachel A. Chamberlin、Michael R. Crampton
DOI:10.1039/p29950001831
日期:——
For each substrate reactions with n-butylamine show a first order dependence on the amine concentration indicating that nucleophilic attack is rate-limiting. However, the reactions with pyrrolidine and with piperidine are subject to general base catalysis and it is argued that here the deprotonation of the initially formed zwitterionic intermediates is rate determining. The results are compared and
正丁胺,吡咯烷和哌啶与DMSO中的苯基2,4,6-三硝基苯基醚3的反应导致加合物的快速可逆形成,方法是在3位反应,然后在1位进攻,导致苯氧基的取代。与苯基2,4-二硝基萘醚1a和苯基2,4-二硝基苯基醚8,替换是唯一观察到的过程。对于每种底物,与正丁胺的反应均显示出对胺浓度的一级依赖性,表明亲核攻击是限速的。然而,与吡咯烷和哌啶的反应经受一般的碱催化,并且据认为,此处最初形成的两性离子中间体的去质子化是决定速率的。将结果与相应的乙醚(其中碱催化涉及SB-GA机理)和苯硫醚的结果进行对比和对比。