Bourgeonal is an

aromatic In organic chemistry, aromaticity is a chemical property describing the way in which a conjugated system, conjugated ring of unsaturated bonds, lone pairs, or empty orbitals exhibits a stabilization stronger than would be expected from conjugati ...

aldehyde In organic chemistry, an aldehyde () (lat. ''al''cohol ''dehyd''rogenatum, dehydrogenated alcohol) is an organic compound containing a functional group with the structure . The functional group itself (without the "R" side chain) can be referred ...

used in perfumery. It has a fragrance reminiscent of

lily of the valley Lily of the valley (''Convallaria majalis'' ), sometimes written lily-of-the-valley, is a woodland flowering plant with sweetly scented, pendent, bell-shaped white flowers borne in sprays in spring. It is native throughout the cool temperate No ...

, otherwise described as floral, watery, green, and aldehydic. It is a pale yellow liquid at room temperature.

Synthesis

Industrial synthesis of bourgeonal involves a mixed

aldol reaction The aldol reaction (aldol addition) is a Chemical reaction, reaction in organic chemistry that combines two Carbonyl group, carbonyl compounds (e.g. aldehydes or ketones) to form a new β-hydroxy carbonyl compound. Its simplest form might invol ...

of 4-''tert''-butylbenzaldehyde and

acetaldehyde Acetaldehyde (IUPAC systematic name ethanal) is an organic compound, organic chemical compound with the chemical formula, formula , sometimes abbreviated as . It is a colorless liquid or gas, boiling near room temperature. It is one of the most ...

, followed by

hydrogenation Hydrogenation is a chemical reaction between molecular hydrogen (H2) and another compound or element, usually in the presence of a catalyst such as nickel, palladium or platinum. The process is commonly employed to redox, reduce or Saturated ...

. Alternatively it may be produced by the

Heck reaction The Heck reaction (also called the Mizoroki–Heck reaction) is the chemical reaction of an unsaturated halide (or triflate) with an alkene in the presence of a base and a palladium catalyst to form a substituted alkene. It is named after T ...

of 1-bromo-4-''tert''-butylbenzene with 2-hydroxymethylpropene followed by isomerisation.

Biological effects

In a 2003 study it was found that in vitro, bourgeonal acts as a chemo-attractant for human

spermatozoa A spermatozoon (; also spelled spermatozoön; : spermatozoa; ) is a motile sperm cell (biology), cell produced by male animals relying on internal fertilization. A spermatozoon is a moving form of the ploidy, haploid cell (biology), cell that is ...

, activating an olfactory receptor called OR1D2 (formerly called hOR17-4) which opens calcium ion channels in the

sperm Sperm (: sperm or sperms) is the male reproductive Cell (biology), cell, or gamete, in anisogamous forms of sexual reproduction (forms in which there is a larger, female reproductive cell and a smaller, male one). Animals produce motile sperm ...

, leading them to swim twice as fast. Bourgeonal is suspected to be involved in helping sperm locate the

ovum The egg cell or ovum (: ova) is the female reproductive cell, or gamete, in most anisogamous organisms (organisms that reproduce sexually with a larger, female gamete and a smaller, male one). The term is used when the female gamete is not capa ...

. As of 2010, bourgeonal is the only known odor substance to which males have a higher average sensitivity than females. This is thought to be because the same olfactory receptor (OR1D2) is expressed in non-olfactory tissue in sperm cells as well as the olfactory tissue of the nose. The involvement with sperm

chemotaxis Chemotaxis (from ''chemical substance, chemo-'' + ''taxis'') is the movement of an organism or entity in response to a chemical stimulus. Somatic cells, bacteria, and other single-cell organism, single-cell or multicellular organisms direct thei ...

causes an evolutionary pressure for males (

sexual selection Sexual selection is a mechanism of evolution in which members of one sex mate choice, choose mates of the other sex to mating, mate with (intersexual selection), and compete with members of the same sex for access to members of the opposite sex ...

) that causes them to have more OR1D2 receptors on average, both in the nose as well as in sperm.

References

{{reflist Perfume ingredients Aldehydes Tert-butyl compounds