Organic Brønsted Acid‐catalyzed Cycloadditions of o ‐quinone Methides with 1, 3‐dicarbonlys : Facile Access to Xanthenones and Chromanones

Abstract

The in-situ generation of o-quinone methides and their inverse-electron-demand Diels–Alder reaction in the presence of pentacarboxycyclopentadiene—an organic Brønsted acid—has been reported. The synthesis of xanthenones and chromanones in good to excellent yields from the [4 + 2] cycloaddition of quinone methides with 1, 3-dicarbonyls and Meldrum's acid has been accomplished. The development of this method helps in generating a number of biologically potent heterocycles with medicinal applications.