fenchone

Fenchone is a bicyclic monoterpene ketone related to camphor, occurring in essential oils of fennel and some other Apiaceae species. It exists as two enantiomers, (+)-fenchone and (-)-fenchone, which differ in odor and sensory characteristics.

Natural occurrence and isolation: Fenchone is found in fennel essential oil to varying extents depending on chemotype and growing conditions. It is typically isolated from plant material by steam distillation, followed by fractional distillation and chromatographic purification to separate it from other oil constituents.

Chemistry and properties: The molecule features a camphor-like bicyclic skeleton and a ketone functional group. The two enantiomers exhibit distinct olfactory notes, and the overall scent of fennel oil can be influenced by the enantiomeric ratio of fenchone present.

Applications: In perfumery and flavor chemistry, fenchone provides a warm, camphoraceous note with spicy nuances. It is used as a fragrance ingredient and can serve as a chiral building block in organic synthesis and studies of stereochemistry for terpenoids.

Safety and regulation: As with many volatile monoterpenes, fenchone can be irritating to skin and mucous membranes in concentrated form and should be handled with standard safety precautions. Its use in consumer products is subject to regulatory controls for fragrance and flavor ingredients in different jurisdictions.

See also: carvone, limonene.