Recently the Firmenich group isolated β-damascenone from Bulgarian rose oils and also β-damascone from Burley tobacco oil. Although these compounds are isomers of ionones, they are reported to possess a strong rosy smell. These compounds have received much attention as important ingredients in modern perfumery. On the other hand, Cookson report δ-damascone has an odor reminiscent of β-damascenone. Nevertheless it is actually an isomer of β-damascone.
Based upon the relationship between molecular structure and organolelptic properties, we have been interested in 2, 2, 4dimethyl-3-butenoylbicyclo[2,2,1]heptene derivatives. It has a structure such that a new bond is formed between the methyl group at C6 position and the methylene at C3 position in compound (1), resulting in fixing of the cyclohexene ring in compound (1) to a complete boat form. There, it seems to be an attractive problem to synthesize and know the odor of compound (2) and its derivatives.