RING OPENING RING CLOSURE REACTIONS WITH 3-SUBSTITUTED CHROMONES UNDER NUCLEOPHILIC CONDITIONS

This review covers the ring opening ring closure (RORC) reactions of 3-substituted chromones with a variety of nitrogen and carbon nucleophiles. The nucleophilic reagent usually attack 3-substituted chromones at the C-2 position with gamma-pyrone ring opening followed by further transformation during the course of the reaction producing a variety of products depending on the substrate at position 3, the nature of nucleophile and the reaction conditions.