Three-Component Bicyclization Providing an Expedient Access to Pyrano[2′,3′:5,6]pyrano[2,3‑<i>b</i>]pyridines and Its Derivatives

A new three-component bicyclization for the efficient synthesis of a fused pyrano­[2,3-<i>b</i>]­pyridine library has been developed. The syntheses were achieved by reacting diverse C,O-containing nucleophiles, aldehydes, and 2-aminoprop-1-ene-1,1,3-tricarbonitrile under microwave irradiation, providing 50 examples of chemically and biomedically significant pyrano­[2,3-<i>b</i>]­pyridine analogues with the concomitant formation of two new rings and four σ bonds. This procedure features short reaction times, low-cost, and easily available starting materials, reliable scalability and mild reaction conditions, as well as operational simplicity