2-Furanone, also known as γ-crotonolactone (GCL), is a heterocyclic organic compound. Classified as a lactone, this colourless liquid is colloquially called "butenolide." As a class of compounds, substituted derivatives, which are not in fact prepared from the parent 2-furanone, are called butenolides.
Synthesis and reactions
2-Furanone is prepared by oxidation of furfural:
It exists in equilibrium with the tautomer 2-hydroxyfuran, which serves as an intermediate in the interconversion between the β- and α-furanones. The β form is the more stable. The interconversion is catalyzed by base.
2-Furanones can be converted to furans by a two-step process of reduction followed by dehydration. First the carbon-oxygen double bond is reduced by trimethylsilylation of the oxygen centre.