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.
