Easily accessible dihydropyrans 9, 10, 12 and 19 are precursors for the synthesis of 6-substituted 5,6-dihydro-2 (2 H)-pyranones and 6-substituted tetrahydro-2-pyranones. Syntheses of massoia lactone ( 3), argentilactone ( 5), tuberolactone ( 4) and jasmine lactone ( 2) from acrolein ( 6), acrolein dimer ( 7) or glutaraldehyde ( 16) are described.