Ammonium-type Basic Ionic Liquid; ۲-(۲-Hydroxyethoxy)ethaneammonium Formate: Promote Green and Efficient Multicomponent Tandem Synthesis of ۴H-pyrans and ۴H-chromenes

A facile, convenient, green and environmentally benign one-pot three-component synthesis of poly-functionalized ۴H-pyrans and ۴H-chromenes is described. A basic ionic liquid ۲-(۲-hydroxyethoxy)ethaneammonium formate was found to be an efficient catalyst or catalytically active solvent for the synthesis of those important classes of heterocyclic compounds.