Organocatalyzed Reactions Involving 3-Formylchromones and Acetylenedicarboxylates: Efficient Synthesis of Functionalized Benzophenones and Polysubstituted Xanthones

Organocatalyzed reactions between chromones and acetylenedicarboxylates leading either to xanthone derivatives or to functionalized benzophenones are described. The outcome of the reactions was found to depend both on the nature of the chromone substituents and on the basicity of the organocatalyst.