We report a simple, fast, efficient and benign procedure for solvent-free microwave-assisted one-pot synthesis of symmetrical 4H-pyran-4-ones in the presence of polyphosphoric acid or diphosphorous pentoxide. Various 4H-pyran-4-ones were prepared using this very simple and fast green protocol.
cyclization; 4H-pyran-4-one; acid anhydride; synthetic methods; microwave irradiation