An Activated Sulfonylating Agent That Undergoes General Base-Catalyzed Hydrolysis by Amines in Preference to Aminolysis
作者:Wing Y. Tsang、Naveed Ahmed、Karl Hemming、Michael I. Page
DOI:10.1021/jo800407x
日期:2008.6.1
base-catalyzed mechanism for hydrolysis rather than nucleophilic attack was also deduced for the reaction of N-benzyl-4,4-dimethyl-3-oxo-β-sultam with carboxylate anions based on a SKIE of 1.7−1.9 and rate constants which fit the Bronsted plot for amines. In contrast to acyl transfer reactions, those for sulfonyl transfer appear to show an inverse reactivity-selectivity relationship—the most active compounds
与酰基类似,活化的磺酰基衍生物通常在水中与胺进行氨解反应,因为胺的亲核攻击优于水解。然而,尽管是活性磺酰基衍生物,四元杂环磺酰胺β-sultams在水溶液中不进行氨解,而是优先反应仅得到水解产物。在简单的伯胺缓冲溶液中,β-sultams的反应速率显示出对胺浓度的一级依赖性,这归因于胺的一般碱催化水解。甚至是N-苄基-4,4-二甲基-3-氧代-β-sultam(既是β-sultam又是β-内酰胺)在磺酰基中心进行水解而不是在磺酰基或酰基中心进行氨解。溶剂动力学同位素效应(SKIE,胺催化水解的k H 2 O / k D 2 O)对于N-苯甲酰基-β-sultam和N-苄基-4,4-二甲基-3-氧代-β-sultam的水解分别为1.4和1.9 ,分别与一般的碱催化机制兼容。胺催化的水解作用使N-苯甲酰基β-sultam和N-苄基-4,4-二甲基-3-氧代-β-sultam的布朗斯台德β值均为+0