A one-pot synthesis 3-alkoxycarbonyl-3,4-dihydro-2H-pyran-2-ones from vinylidene melderum's acids, dialkyl acetylenedicarboxylates, and simple alcohols.

A one-pot synthesis of 3-alkoxycarbonyl-3,4-dihydro-2H-pyran-2-ones from intermolecular hetero-Diels-Alder reaction between vinylidene Melderum's acids and dialkyl acetylenedicarboxylates, in the presence of simple alcohols at room temperature, is described. The advantages of this procedure are good yields, short reaction time, and easy workup. Antioxidant properties of four derivatives of these 3,4-dihydro-2H-pyran-2-ones, together with their antimicrobial activities, are investigated.