Question

Propose a mechanism for the formation of 9-hydroxynonanoic acid lactone, as show in the preceding figure.

Short answer

Answer

A mechanism for the formation of 9-hydroxynonanoic acid lactone is shown below.

Step-by-step solution

Concept introduction of Lactones

Lactones are the cyclic esters of hydroxycarboxylic acids. Simple lactones that contains five and six-membered rings are more stable than the open-chain hydroxyl acids. Lactones are formed spontaneously under acidic conditions.

Formation of 9-hydroxynonanoic acid lactone

Lactone is formed by the intermolecular esterification of hydroxycarboxylic acids that take place simultaneously and result in the formation of 9-hydroxynonanoic acid lactone.

Mechanism