Reactivity of 2-methylene-1,3-dicarbonyl compounds. syntheses of 2,2,3-trisubstituted-3,4-dihydro-2h-pyrano(3,2-c)(1)benzopyran-5-ones

TLDR: In this article, condensation of 2-methylsulfinylmethyl-1, 3-dicarbonyl compounds (3) with 4-hydroxycoumarin (5) at ambient temperature gave 2.

Abstract: Michael condensation of 2-methylsulfinylmethyl-1, 3-dicarbonyl compounds (3) or 2-methylene-1, 3-dicarbonyl compounds (4) with 4-hydroxycoumarin (5) at ambient temperature gave 2-[(4-hydroxycoumarin-3-yl)methyl]-1, 3-dicarbonyl compounds (6). Treatment of 6 with methanolic hydrogen chloride resulted in the regioselective formation of 2, 2, 3-trisubstituted-3, 4-dihydro-2H-pyrano[3, 2-c][1]benzopyran-5-ones.