2 Pyrone

2-Pyrone (α-pyrone or pyran-2-one) is an unsaturated cyclic chemical compound with the molecular formula C₅H₄O₂. It is isomeric with 4-pyrone.

2-Pyrone is used in organic synthesis as a building block for more complex chemical structures because it may participate in a variety of cycloaddition reactions to form bicyclic lactones. For example, it readily undergoes Diels-Alder reactions with alkynes producing, upon loss of carbon dioxide, substituted benzenes. The Gogte Synthesis (1938) is a method for the alkylation of certain pyrones with acid chlorides.

The most common natural products containing a 2-pyrone are the bufanolides and kavalactones. Oxovitisin A, a pyranoanthocyanin found in wine, also contains a 2-pyrone element.