Efficient One-Pot Synthesisof Substituted 4,7-Phenanthroline, Pyrano-[3,2-f]quinoline and Pyrano[3,2-g]quinoline Derivatives by Aza-Diels-Alder Reaction

A mild and efficient method for the synthesis of pyrano[3,2-f]quinoline and 4,7-phenanthroline derivatives via three-component domino reaction of heterocyclic amines, aldehydes, and terminal alkyne using BF 3 ·OEt 2 as Lewis acid catalyst is described. The features of this procedure are mild reaction conditions, good to high yields, and operational simplicity.