Organocatalysed C-2 and C-3 functionalisation of chromones.

Abstract

This review highlights the recent advancements in organocatalysed Michael addition reactions involving chromones, an important class of heterocyclic compounds with significant biological and pharmacological properties. Chromones, with their versatile conjugated structure, act as both electrophilic and nucleophilic partners, providing an ideal platform to synthesise diverse stereochemically enriched molecular frameworks. The work highlights various organocatalysed examples using chiral carbenes, phosphoric acids, thioureas and squaramides, that have demonstrated high efficiency and stereocontrol in a range of reactions. Mechanistic insights into how these catalytic systems activate the chromone scaffold and promote enantioselective transformations are also discussed in detail. Finally, we underline emerging trends and future directions in this research area, addressing current limitations, such as the need for more efficient catalytic systems and broader substrate compatibility.