An efficient Friedel–Crafts alkylation for the synthesis of 3-indolyl-3-hydroxy oxindoles and unsymmetrical 3,3-diaryl oxindoles catalyzed by Dabco-based ionic liquids in water

摘要: A convenient and rapid method for the syntheses of 3-indolyl-3-hydroxy oxindoles unsymmetrical 3,3-diaryl has been developed by using Dabco-based ionic liquid catalysts. The two catalysts, [Dabco-H][BF4] [Dabco-H][HSO4] were found to be highly efficient catalysts controlled 3-indolylation isatins in water. When was employed as catalyst water at 55 °C, reaction between indoles stops step addition components afforded oxindoles. While increasing temperature 90 could drive further afford symmetrical 3,3-diindolyl By kinds liquids, a two-step protocol synthesis also developed. use medium makes process environmentally benign. can recycled five times without activity loss.