Noun
sirenin (uncountable)
(organic chemistry) A sexual attraction pheromone in some fungi of the genus Allomyces.
Aldrichimica Acta Volume 30 No 4 (pdf) from Sigma-Aldrich
One notable early example was reported by Corey and involved an intramolecular cyclopropanation that was used in the synthesis of sirenin and has since been achieved asymmetrically using a chiral copper catalyst.