The regioselective ipso-formylation of electron-rich, 3,4-push-pull-substituted 2-chlorothiophenes under Vilsmeier-Haack conditions was performed in good yields. The synthetic scope of this new reaction was explored using various halothiophenes, chloroanilines, and 1-methyl-3-chloroindole. In comparison with their structural C-H analogs the chlorinated thiophenes, anilines, and the indole proved to be less reactive toward electrophilic attack by chloromethyleniminium salts.
在Vilsmeier-Haack条件下,对电子丰富、3,4-推拉取代的2-氯噻吩进行了区域选择性的异位甲酰化反应,并以较好的产率获得了产物。通过使用不同的卤代噻吩、氯代苯胺和1-甲基-3-氯吲哚,探索了这一新反应的合成范围。与它们的C-H结构类似物相比,氯化的噻吩、苯胺和吲哚对氯甲基亚胺盐的亲电攻击表现出较低的活性。