Sc(OTf)3-Mediated One-Pot Synthesis of Coumarin-Fused Furans: A Thiol-Dependent Reaction for the Easy Access of 2-Phenyl-4H-furo[3,2-c]chromen-4-ones

Herein, we report a simple and efficient method for the preparation of novel thioether-linked coumarin-fused furans from the one-pot three-component reaction of arylglyoxal, 4-hydroxycoumarin, and various aromatic thiols in the presence of Sc(OTf)(3) as a catalyst. This methodology is also applicable to cyclic 1,3-dicarbonyls such as cyclohexane-1,3-dione and dimedone. Depending upon the thiols, this methodology can either give a three-component thioether-linked coumarin-fused furan (4) or a twocomponent furocoumarin product (5). Wide substrate scope, good to excellent yields, and products having more than one pharmaceutically important motif are the salient features of this methodology.

Automated summary

Here, we describe a simple and efficient method for the synthesis of novel thioether-linked coumarin-fused furans. By employing a one-pot three-component reaction using arylglyoxal, 4-hydroxycoumarin, and various aromatic thiols as starting materials and Sc(OTf)(3) as catalyst, we successfully obtained the desired products. This methodology is also applicable to cyclic 1,3-dicarbonyls and allows for the formation of either a three-component thioether-linked coumarin-fused furan or a two-component furocoumarin product, depending on the choice of thiols. The wide substrate scope, high yields, and presence of important pharmaceutically relevant motifs make this methodology highly valuable.