Six-Membered Silacycle Odorants: Synthesis and Olfactory Characterization of Si Analogues of Artemone, β-Dynascone, and Herbac

Si-Artemone (4a), Si-beta-Dynascone (5a), and Si-Herbac 6a, which are Si analogues of the commercial fragrance ingredients Artemone (1), beta-Dynascone (2), and Herbac (3), were synthesized expediently by the insertion of terminal alkynes into silacyclobutane 7a. The sensory characterization results revealed that 4a and 6a had quite similar odor qualities compared with those of 1 and 3, whereas 5a had a totally different odor character relative to that of 2. In terms of the odor threshold values, that of 4a was slightly more substantive than that of its carbon analogue 1, 6a was less potent than its carbon analogue 3, whereas that of 5a was approximately one-sixth that of its carbon analogue 2.