Hedione, or methyl dihydrojasmonate, which was isolated and synthesized in 1962, exists in nature in jasmine and in tea. Its first major use was in Edmond Roudnitska 's Eau Sauvage; he was to use it again often after that. Hedione's effect is to reinforce diffusion, freshness and volume in a composition, as an "odor booster." It is very commonly used today in the majority of perfumes. Taken in isolation, hedione has a light, subtle, green, transparent jasmine note, and gives an impression of "perfumed air."
From auparfum.com [Translated by JaimeB]