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Synthesis of the Enantiomers of (Z)-5-Muscenone and (E)-5-Muscenone

IP.com Disclosure Number: IPCOM000007773D
Publication Date: 2002-Apr-23
Document File: 1 page(s) / 39K

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Charles Fehr, Jose Galindo, Olivier Etter: AUTHOR

Abstract

(Z)-5-Muscenone and (E)-5-Muscenone, and their odorant characteristics are described. These two isomers of 3-methyl-cyclopentadec-5-en-1-one have useful musky odors.

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Synthesis of the Enantiomers of (Z)-5-Muscenone and (E)-5-Muscenone

Authors: CharlesFehr, José Galindo, Olivier Etter.

The most precious isomers of the perfume component “Muscenone” (Firmenich SA) are the (Z)- and (E)-5-muscenones 1 and 2. The (Z)-isomer 1 is particularly appreciated for its better top note and its nitromusk character.


In view of the growing interest and research activities devoted to the enantiomers of muscone [1], of which the natural (R)-(-)-enantiomer is stronger [2], we decided to prepare the enantiomers of (Z)-5-muscenone and (E)-5-muscenone [3].

(S)-(+)-3 (97% ee) was submitted to an Eschenmoser fragmentation [4] to afford (R)-(-)-4. Lindlar hydrogenation afforded (R)-(+)-1 (97% ee; [a]D 20 (MeOH, c = 0.08) +8.1), and Li-reduction [6] furnished (R)-(-)-2 (97% ee; [a]D 20 (MeOH, c = 0.06) -3.3). Whereas (R)-1 and (R)-2 represent strong musk odorants, (S)-1 and (S)-2, prepared in analogous manner, are only weakly musky.

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[1] A. Alexakis, C. Benhaïm, X. Fournioux, A. van den Heuvel, J.-M. Levêque, S. March, S. Rosset, Synlett. 1999, 1811 and references cited therein.

[2] W. Pickenhagen, ACS Symposium Ser. 388, 1989, 151.

[3] For the synthesis of a mixture of isomers of (S)-1 and (S)-2 (+positional isomers?): D.-S. Wang, D.-Q. Wang, C.-H. Zhou, Huaxue Xuebao 1995, 53, 909; see also: D. Wang, C. Zhou, D. Wang, Chin. Chem. Lett. 1992, 3, 235.

[4] J. Schreiber, D. Felix, A. Eschenmoser, M. Winter, F. Gautschi, K. H. Schulte-Elte, E. Sundt, G. O...