Chiral building block
Wiley InterScience Backfile Collection 1832-2000
Chemistry and Pharmacology
Starting from a cycloalkanone and the chiral building blocks 2 or 3 both enantiomers of 13-tetradecanolide (1, n = 14) were prepared by ring-enlargement reactions. Cycloundeca-none (4) was α-alkylated with the protected hydroxy halide 2 derived from (S)-(-)-methyl lactate. Acid-catalyzed cyclization, oxidative cleavage of the enol ether double bond by PCC, and reduction of the carbonyl group via a tosylhydrazone led to the (S)-configured target molecule (+)-8 (98.0% ee), thus indicating the sequence proceeded with clean retention of configuration. Likewise, the naturally occurring (R)-enantiomer (-)-8 (〉99.8% ee) was synthesized from cyclodecanone (9) and the chiral building block 3. Aided by CD conformational analysis the olfactory properties of both enantiomers were compared with those of the regioisomers (12R)-( + )- and (12S)-(-)-12-methyl-13-tridecanolide previously prepared by the same method.
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