The influence of steric effects on the kinetics and mechanism of S<sub>N</sub>Ar reactions of 1-phenoxy-nitrobenzenes with aliphatic primary amines in acetonitrile
作者:Chukwuemeka Isanbor
DOI:10.1002/poc.3687
日期:2017.11
be mediated by reduced steric congestion around the reaction centre. Specific steric effects, leading to rate retardation, are noted for the ortho‐CF3 group. In general, reactant‐bearing ortho‐CF3 group were subject to base catalysis irrespective of the amine nucleophile and values of kAm/k−1 are reduced as the size of the amine get bulkier. This is likely to reflect increases in values of k−1 coupled
速率常数报道的1-苯氧基二硝基苯,反应3,1-苯氧基dinitrotrifluoromethylbenzenes,4,与Ñ丙胺,和乙腈作为溶剂1- methylheptylamine。将结果与先前报道的正丁胺,吡咯烷和哌啶的结果进行比较。减少的环活化导致亲核攻击的k 1值较低,尽管这可能是由于反应中心周围的空间拥塞减少所引起的。对于邻-CF 3组,存在导致速率减慢的特定空间效应。通常,含反应物的邻CF 3不论胺亲核试剂如何,组均进行碱催化,并且随着胺的体积变大,k Am / k -1的值减小。这可能反映出k -1值的增加以及k Am值的减小,因为从两性离子中间体到催化胺的质子转移在热力学上变得不太有利。