Kinetic Study on S<sub>N</sub>Ar Reaction of 1-(Y-Substituted-phenoxy)-2,4-dinitrobenzenes with Cyclic Secondary Amines in Acetonitrile: Evidence for Cyclic Transition-State Structure
作者:Ik-Hwan Um、Min-Young Kim、Tae-Ah Kang、Julian M. Dust
DOI:10.1021/jo5011872
日期:2014.8.1
linear with βnuc = 1.10 and 0.85 for the uncatalyzed and catalyzed reactions, respectively, while the Yukawa–Tsuno plots for the reactions of 1a–1h with piperidine result in excellent linear correlations with ρY = 1.85 and r = 0.27 for the uncatalyzed reaction and ρY = 0.73 and r = 0.23 for the catalyzed reaction. The catalytic effect decreases with increasing amine basicity or electron-withdrawing ability
据报道,动力学研究了MeCN中1-(Y-取代的苯氧基)-2,4-二硝基苯(1a – 1h)与胺的S N Ar反应。拟一级反应速率常数对胺浓度的曲线向上弯曲,表明该反应被第二个胺分子催化。1-(4-硝基苯基)的反应的布朗斯台德型曲线-2,4-二硝基苯(1A与仲胺)是线性的与β NUC = 1.10和0.85的非催化和催化反应,分别,而Yukawa-津野地块为的反应1A - 1H用哌啶结果在良好的线性关系与ρ ŷ = 1.85和- [R= 0.27对于非催化反应和ρ ÿ = 0.73和- [R = 0.23的催化反应。随着离去基团中取代基Y的胺碱性或吸电子能力的提高,催化作用降低。由1a与哌啶的催化反应在五个不同温度下测得的速率常数计算得出的活化参数为ΔH ‡ = 0.38 kcal / mol和ΔS ‡ = -55.4 cal /(mol K)。有人提出,迈森海默配合物(MC ±)的催化反应