Bi(iii)-catalyzed synthesis of furocoumarins via a three component reaction of arylglyoxal monohydrates, coumarins and N-substituted anilines

Abstract

We report a bismuth(III)triflate catalyzed novel, efficient and atom-economical one-pot three-component methodology for the synthesis of furo[3,2-c]-coumarins from arylglyoxals, 4-hydroxycoumarins and N-substituted anilines. When using N-methyl aniline, we have obtained both the furocoumarins and three-component adducts, whereas with N,N-dimethyl aniline and N,N-diethyl aniline, the reactions proceed well giving only the three-component adducts. Furthermore, these adducts upon treatment with BF₃·OEt₂ in toluene at 100 °C afforded the desired furo[3,2-c]-coumarins.