Synthesis and olfactory evaluation of (±)-β-irone.

The powdery scent of orris root oil adds elegance and depth to any fragrance. However, orris root oil is one of the most expensive essential oils due to a lengthy six-year production process. If compounds with the powdery scent could be supplied by chemical synthesis at a lower cost than natural products, there would be a large demand. In the course of our research into the synthesis and olfactory evaluation of irone isomers, we found that (±)-β-irone, a minor component of orris root oil, has an excellent powdery aroma. In this study, we report a new synthetic method for (±)-β-irone and the results of its olfactory evaluation. The synthesis of (±)-β-irone was accomplished using commercially available 3-methylcyclohexanone as the starting material. The olfactory evaluation of synthesized (±)-β-irone was performed. (±)-β-Irone has been found to have a strong, transparent, fruity green top note, a rich violet floral heart note, and a clear, powerful, and long-lasting powdery last note with a woody odor. We considered that some part of the powdery fragrance of orris root oil originates from β-irone, and that β-irone is an excellent flavoring and fragrance material that can be used as a substitute for natural orris root oil.