Treatment of 3-hydroxyoxindoles with trichloroacetonitrile (1.3 equiv.) and a catalytic amount of DBU (0.1 equiv.) followed by addition of nucleophiles (1.5 equiv.) and diphenylphosphoric acid (0.2 equiv.) afforded the 3,3-disubstituted oxindoles in good to excellent yields. DFT computations supported the notion that the reaction went through the 1-alkyl-2-oxo-2H-indol-1-ium intermediate.
用
三氯乙腈(1.3 个等量物)和催化量的
DBU(0.1 个等量物)处理 3- 羟基
吲哚,然后加入亲核物(1.5 个等量物)和
二苯基磷酸(0.2 个等量物),可以得到 3,3-二取代的
吲哚,收率从良好到极佳。DFT 计算证明,反应是通过 1-烷基-2-氧代-
2H-吲哚-1-鎓中间体进行的。