A new regioselective synthesis of 2,3,4,5-tetrahydro-6H-oxepino[3,2-c]pyran-6-ones, and [1]benzopyran-6-ones

Article abstract of DOI:10.1002/jhet.5570250252

Through an anti-Markovnikow hydration of some olefin derivatives of 4-hydroxy-2-pyrones, and 4-hydroxy-coumarins, followed by a regioselective intramolecular dehydration, involving the primary alcohols obtained and the enolic oxygen of the rings, promoted by Amberlyst 15 in boiling toluene, the new heterocycles 2,3,4,5-tetrahydro-6H-oxepino[3,2-c]pyran-6-one and [1]benzopyran-6-ones, were obtained in fair yields.