2-Furanone is a heterocyclic organic compound. It is also known as γ-crotonolactone (GCL), as it is formally the lactone derived from γ-hydroxyisocrotonic acid. The chemical is colloquially called "butenolide", and is the parent structure for the butenolide class of compounds. It is a colourless liquid.

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. Furanone is thought to contribute to the unique taste of Maple syrup.