In the perfumery as well as in the flavour industry a lot of efforts are devoted today to the replacement of expensive naturally occurring raw materials or the reproduction of original organoleptic effects by making use of new chemicals. Among the numerous synthetic odorants prepared in a recent past, bi-, tri- or polycyclic derivatives of decalin can be cited as examples, as well as bicyclo[2.2.1]heptane, bicyclo[2.2.2]octane, cedrene or caryophyllene derivatives.
For instance, the tricyclic compound of formula ##STR2## is appreciated in the art for its original floral and woody odour--see e.g. Swiss Pat. No. 547 850--, as well as the compound of formula ##STR3## which is used in perfumery for developing or enhancing woody and spicy odour notes--see e.g. Swiss Pat. No. 557 870--. As further example of tricyclic fragrant compounds, one can also cite the compound of formula ##STR4## characterized by its original odour note, at the same time sweet, fresh, spicy and herbaceous--see e.g. DE-OS No. 28 26 302.
Notwithstanding the relative abundance of tricyclic fragrant compounds known in the art, there still remains a constant need of enrichment of the palette of the perfumer, or of the flavourist, by the finding of new active substances.