New macrocyclic musk compounds.

The syntheses and olfactory evaluations of eight new macrocyclic musks with a 1,6-dioxa structure (1a-d and 1'a-d) as well as of twelve optically active 3-methyl macrolides (5a-c and 5'a-c) are reported. These macrocycles were synthesized via intramolecular metathesis mediated by the Grubbs catalyst. Despite the absence of a C=O function, the 1,6-dioxa compounds, both unsaturated (1) and saturated (1'), possess musky odors similar to those of macrocyclic ketones and lactones. Especially 16-membered rings were found to display an intense and pleasant musk character. However, in the case of optically active 3-methyl macrolides (5, 5'), only the (R)-configured 15- and 16-membered rings had intense and pleasant musk notes.