通过醇与芳基卤的交叉偶联形成芳基-烷基醚键代表了对经典S N 2 方法的有用的战略偏离。过去几年出现了许多依赖钯基、铜基和镍基催化系统的策略。在此,我们公开了一种镍催化电化学驱动方案,以一种操作简单的方式在广泛的底物范围内实现这种有用的转化。这种电化学方法不需要强碱、昂贵的外源过渡金属催化剂(例如铱、钌),并且可以轻松地在批量或流动设置中扩大规模。有趣的是,与机械相关的光化学变体相比,电子醚化表现出增强的底物范围,因为它耐受醇亲核试剂中的叔胺官能团。
The reactions of 2-methoxypyridine with haloalkanes without solvent and catalyst under microwave irradiation (100-200 degrees C, 5 min) yielded the corresponding N-alkyl-2(1H)-pyridones in good to moderate yields. However, the reactions were sensitive to length of haloalkanes. In contrast, the reactions of 2-alkoxypyridines with corresponding iodoalkanes under microwave irradiation (150 degrees C) proceeded rapidly without catalyst and solvent, and were complete within 5 min to afford N-alkyl-2(1H)-pyridones in good to excellent yields.
Fuerst; Feustel, CHEMTECH, 1958, vol. 10, p. 693,698, 699