Novel Approach to the Synthesis of 6‐Substituted 5,6‐Dihydro‐2(2H)‐pyranones

Easily accessible dihydropyrans 9, 10, 12 and 19 are precursors for the synthesis of 6‐substituted 5,6‐dihydro‐2 (2H)‐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.