Enzyme-Mediated Preparation of the Single Enantiomers of the Olfactory Active Components of the Woody Odorant Timberol.

Enantiomerically pure (3S)-3a and -3b, the olfactory active forms of 1-(2,2,6-trimethylcyclohexyl)hexan-3-ol. components of the commercial woody odorant Timberol(R), are obtained by lipase-PS-mediated enantioselective acetylation of the allylic alcohols 6 and 7 and of the saturated alcohol 3. These materials, as mixtures of diastereoisomers, provided (3R)-configured transformation products. However, whereas in the conversion of 6 and 7 there is no diastereoselection, 3 provided the acetate of (1'S,3R,6'R)-3c much more rapidly than that of the diastereoisomer (1'R,3R,6'S)-3d (Scheme 3). Inversion of the configuration at C(3) of the side chain of the olfactory inactive (3R)-materials obtained as acetates in the enzymic treatment of 6, 7, and 3 also provided, eventually, the desired olfactory active (3S)-products.