acetals) and carbanions. It is shown that the nucleophilic reactivities of enamines cover more than ten orders of magnitude, comparable to enol ethers on the low reactivity end and to carbanions on the high reactivity end. Since the products of N-attack are thermodynamically less stable than the reactants, the observed rate constants refer to the formation of the carbon bond;carbon bonds. In some cases
在
二氯甲烷中用光度法研究了
苯甲基阳离子与22种
烯胺,3种
吡咯和3种
吲哚的反应动力学。这些富含电子的pi系统的亲核参数N和斜率参数s从等式log k(20摄氏度)= s(E + N)导出,并与其他pi系统(甲
硅烷基
烯醇醚,甲
硅烷基)的亲核性进行了比较
乙烯酮缩醛)和
碳负离子。结果表明,
烯胺的亲核反应活性覆盖了十多个数量级,与低反应性末端的
烯醇醚和高反应性末端的
碳负离子相当。由于N攻击的产物在热力学上不如反应物稳定,因此观察到的速率常数是指
碳键,
碳键的形成。在某些情况下,