Domingo Luis R, Sáez José A
Departamento de Química Orgánica, Universidad de Valencia, Dr. Moliner 50, E-46100, Burjassot, Valencia, Spain.
Org Biomol Chem. 2009 Sep 7;7(17):3576-83. doi: 10.1039/b909611f. Epub 2009 Jul 10.
A good correlation between the activation energy and the polar character of Diels-Alder reactions measured as the charge transfer at the transition state structure has been found. This electronic parameter controls the reaction rate to an even greater extent than other recognized structural features. The proposed polar mechanism, which is characterized by the electrophilic/nucleophilic interactions at the transition state structure, can be easily predicted by analyzing the electrophilicity/nucleophilicity indices defined within the conceptual density functional theory. Due to the significance of the polarity of the reaction, Diels-Alder reactions should be classified as non-polar (N), polar (P), and ionic (I).
已发现活化能与狄尔斯-阿尔德反应的极性特征（以过渡态结构处的电荷转移来衡量）之间存在良好的相关性。与其他公认的结构特征相比，这个电子参数对反应速率的控制作用更大。所提出的极性机理以过渡态结构处的亲电/亲核相互作用为特征，通过分析概念密度泛函理论中定义的亲电/亲核性指数可以很容易地预测。由于反应极性的重要性，狄尔斯-阿尔德反应应分为非极性（N）、极性（P）和离子性（I）。
