Three-component domino reaction in Triton B: A facile synthesis of 4H-chromene derivatives

Abstract

Herein, we report an unprecedented one-pot domino synthesis of indole- or naphthol-tethered biologically relevant 4H-chromene derivatives from readily accessible salicylaldehydes, malononitrile, and indoles/β-naphthols employing efficient, inexpensive, non-metallic Benzyltrimethylammonium hydroxide (Triton B) as a base promoter. This protocol is an atom-economic three-component one-pot reaction that delivers various 4H-chromenes with good substrate scope and excellent yields. Moreover, this protocol compares the synthesis of 4H- chromene derivatives with the earlier reported 2H-chromenes avoiding the time and solvent-consuming tedious column chromatography.