Rates and equilibria of the reaction of 2,4,6-triphenylthiopyrylium ion with piperidine and morpholine in dimethyl sulfoxide. An unusual proton transfer to a nitrogen base
作者:Giancarlo Doddi、Gianfranco Ercolani
DOI:10.1021/ja00335a036
日期:1984.11
The complete set of kinetic and equilibrium constants of the reaction of 2,4,6-triphenylthiopyrylium ion (1) with piperidine and morpholine has been obtained in Me2SO at 25°C. The reaction involves the formation of both the corresponding 2H- and 4H-thiopyrans, which equilibrate to form only the more stable 2H adduct. The kinetic data are consistent with a two-step process wherein the proton transfer
2,4,6-三苯基噻吩鎓离子 (1) 与哌啶和吗啉在 Me2SO 中反应的整套动力学和平衡常数已在 25°C 下获得。该反应涉及形成相应的 2H-和 4H-噻喃,它们平衡以仅形成更稳定的 2H 加合物。动力学数据与两步法一致,其中从质子化的 2H-和 4H-噻喃中间体到胺的质子转移是速率控制步骤。溶剂化质子在热力学上有利的质子转移到中性加合物显示出低于扩散极限的速率,而观察到的布朗斯特系数表明扩散控制过程。这种行为是根据本征机制讨论的。讨论了影响亲核加成的因素,并与之前报道的 1 与伯胺的反应进行了比较。© 1984 美国化学学会。