log kEVE. The monoparametric inverse relationship between rate and basicity Dπ parameters shows that solvent behaves as a nucleophile. This relationship is largely improved by a bi-parametric equation with solvent basicity and polarity contributions. The negative polarity contribution of the solvent to the rate is discussed in terms of change of polarity for these D.A. reactions going from reactants
N-(2',4'-dichloro-6'-oxo-2',4'-环
己二烯-1'-亚烷基)-4-
硝基苯甲酰胺的Diels-Alder(
DA)反应的溶剂效应为(1)动力学研究。1,具有2,3-二甲基
丁二烯(
DMB),主要表现为异二烯亲和性,而与乙基
乙烯基醚(EVE),则作为异二烯反应。溶剂化的机理在两个
DA反应中都相同,并且涉及1,因为log k
DMB与log k EVE线性相关。率和碱度d之间的monoparametric反比关系π参数显示溶剂表现为亲核试剂。通过具有溶剂碱性和极性贡献的双参数方程式,可以大大改善这种关系。对于这些
DA反应从反应物到过渡态的极性变化,讨论了溶剂对速率的负极性影响。