Mülheim chemists unveil the odorous principle of vetiver oil

(+)-2-epi-Ziza-6(13)en-3-one is the smelling principle

The smelling principle of vetiver oil was one of the last mysteries of essential oil research and natural product chemistry. Albeit one of the finest ingredients, appearing in over a third of all fine fragrances, its complex composition of hundreds of compounds prevented the assignment of the vector responsible for the typical suave and sweet transparent odor.

A group of researchers around Ben List of the Max-Planck-Institut für Kohlenforschung in Mülheim and Philip Kraft of the Givaudan Fragrance Research in Kemptthal has proven by an 11-step total synthesis, featuring a novel asymmetric organocatalytic Mukaiyama–Michael addition, that (+)-2-epi-Ziza-6(13)en-3-one is the smelling principle of vetiver. The olfactory evaluation of the synthesized material revealed a remarkably low odor threshold of 29 pg/L air.

The astounding odor similarity with the perfumery material Iso E Super was rationalized with a superposition on its odor vector arborone. Since the latter was held responsible for the quasi-pheromone-like attraction of Iso E Super, interacting with the vomeronasal receptor VN1R1, this similarity could explain the sensual erogenous aura of vetiver and its immense popularity in perfumery. 

The findings were now published in the article "The Odorous Principle of Vetiver Oil, Unveiled by Chemical Synthesis" in  “Angewandte Chemie International Edition”.

Jie Ouyang, Hanyong Bae, Samuel Jordi, Quang Minh Dao, Sandro Dossenbach, Stefanie Dehn, Julia Beatrice Lingnau, Chandra Kanta De, Philip Kraft und Benjamin List, Angew. Chem. Int. Ed. 2020.
https://doi.org/10.1002/anie.202014609