Preparation and Odor Evaluation of Both Enantiomers of 3,4,4aα,5,6,7,8,8aβ-Octahydro-5,5,8aβ-trimethyl-2(1H)-naphthalenone and 1,2α,3,4,4aβ,5,6,7,8,8aβ-Decahydro-5,5,8aβ-trimethyl-2β-naphthalenyl Acetate,Four Woody Odorants

The enantiomeric decahydro-2-naphthalenols (+)- 5 and (?)-5 were prepared by enantioselective hydrolysis of the racemic chloroacetate (±)- 2 catalyzed by porcine pancreatic lipase, and converted to the corresponding acetates (+)- 1 and (?)- 1 and ketones (+)- 6 and (?)- 6 . The absolute configurations of the ketones, alcohols, and acetates were established by chemical correlation with natural manool ((+)- 7 ) by making use of a retro-ene cleavage reaction of the known manool degradation product 8 to (?)- 6 . A distinct odour difference between the two enantiomers of each pair (+)- 1 /(?)- 1 and (+)- 6 /(?)- 6 has been found.     

Synthesis and transformations of (±)-trans-4aβ(H), saα(H)-octahydro-4α,7β-dimethyl-2H-1-benzopyran-2-one

Hydrogenation of 4,7-dimethylcoumarin ( 1 ) in alkaline medium has been shown to furnish a mixture of (±)-trans-4aβ(H),8aα(H)-octahydro-4α,7β-dimethyl-2H-1-benzopyran-2-one ( 2 ), (±)-trans-4aβ(H),8aα(H)-octahydro-4α,7α-dimethyl-2H-1-benzopyran-2-one ( 3 ) and (±)-cis-4aα(H),8aα(H)-octahydro-4α,7α-dimethyl-2H-1-benzopyran-2-one ( 4 ) in 40:25:35:ratio, respectively. The stereochemistry of the major hydrogenation product 2 , has been established by transforming it to p-menthane derivatives e.g. (±)-2 (R)-[2′(R)hydroxy-4′(R) methylcyclohex-(1′S)-yl]propan-1-ol ( 20 ) and (±)-trans-3α,6β-dimethyl-3aβ(H),7aα(H)-octahydrobenzofuran ( 12 ). Starting from a mixture of lactones 2, 3 and 4 , lactone 3 has been obtained in pure state employing a sequence of reactions.