N,N,N′,N′‐Tetrabromobenzene‐1,3‐disulfonamide Catalyzed Synthesis of New Spiro[chroman‐3,2′‐chromeno[2,3‐b]furan]‐2,4,4′‐(3′H)‐trione Derivatives

Abstract

An efficient approach for one‐pot synthesis of biologically active new spiro[chroman‐3,2′‐chromeno[2,3‐b]furan]‐2,4,4′‐(3′H)‐trione derivatives from tandem Knoevenagel–Michel addition–heterocyclization reaction between 4‐hydroxycumarin and various aldehydes in the presence of N,N,N′,N′‐tetrabromobenzene‐1,3‐disulfonamide as an efficient catalyst at ambient temperature under solvent‐free conditions was reported. Simple procedure, high yields, easy work‐up, and reusability of the catalyst are the significant advantages of this process.