Keywords: (R)-4-menthen-3-one, (5S)-methyl-2-isopropyl-3-hexyl-2-cyclohexen-1-one, (3S)-methyl-5-oxoundecanoic acid methyl ester, (3S)-methylundecanoic acid, (3S)-methyl-1-undecanol, 1-bromo-3S-methylundecane, 1-bromo-2S-methyldecane, (S,S,S)-diprionylacetate.We have previously demonstrated the capabilities for the synthetic use of (R)-4-menthen-3-one (1), which is available from l-menthol, that were connected with the capability of conjugated enones for selective 1,2-addition of organometallic reagents with subsequent rearrangement of the resulting tertiary allyl alcohols through the action of Cr(VI) [3,4] using as examples (14S)-methyloctadec-1-ene [1], a sex pheromone of the peach leafminer moth Lyonetia clerkella, and (R)-3-methyl-J-butyrolactone, a synthon for optically active vitamins E and K, in addition to the terpene dolichol and its analogs [2].Herein this synthetic approach is expanded using as examples (3S)-methylundec-1-ylbromide (6) and (2S)-methyldec-1-ylbromide (7), key synthons [5, 6] for (S,S,S)-diprionylacetate (8), a sex pheromone of pine sawflies of the genera Diprion and Neodiprion.Regioselective 1,2-addition of n-C 6 H 13 Li to enone 1 at -78°C and further work up of the intermediate enol with pyridinium chlorochromate (PCC) gave (5S)-methyl-2-isopropyl-3-hexyl-2-cyclohexen-1-one (2). Subsequent ozonolysis of 2 that occurred with loss of the isobutyl moiety and methanolysis led to ketoester 3. Whereas a large excess of ozone is usually 1) Bashkir State University, 450074, Ufa,
