Synthesis 2009(1): 62-68  
DOI: 10.1055/s-0028-1083269
PAPER
© Georg Thieme Verlag Stuttgart ˙ New York

Synthesis and Olfactory Evaluation of (4aR*,8aR*)-1,1,8a-Trimethyl­decahydronaphthalen-4a-ol: A cis-Decalol Intersection Structure of (-)-Patchoulol and (5R*,6S*)-1,1,6-Trimethylspiro[4.5]decan-6-ol

Astrid Jahnkea, Christian Burschkaa, Reinhold Tacke*a, Philip Kraft*b
a Institut für Anorganische Chemie, Universität Würzburg, Am Hubland, 97074 Würzburg, Germany
Fax: +49(931)8884609; e-Mail: r.tacke@mail.uni-wuerzburg.de;
b Givaudan Schweiz AG, Fragrance Research, Überlandstrasse 138, 8600 Dübendorf, Switzerland
Fax: +41(44)8242926; e-Mail: philip.kraft@givaudan.com;
Weitere Informationen

Publikationsverlauf

Received 13 August 2008
Publikationsdatum:
12. Dezember 2008 (online)

Zoom Image

Abstract

Superposition analysis of (-)-patchoulol (1) and the spirocyclic patchouli odorant (5R*,6S*)-1,1,6-trimethylspiro[4.5]decan-6-ol (3) suggested the intersection structure (4aS*,8aS*)-1,1,8a-trimethyldecahydronaphthalen-4a-ol (4) as potential patchouli odorant. The synthesis commenced with the Robinson annulation of mesityl oxide with 2-cyanocyclohexanone, accessible by intramolecular cyclization of pimelonitrile. Weitz-Scheffer epoxidation of the resulting Michael system with hydrogen peroxide in the presence of sodium hydroxide and subsequent Wharton rearrangement employing hydrazine hydrate and acetic acid furnished with complete cis-selectivity (4aR*,8aR*)-8a-hydroxy-5,5-dimethyl-1,2,3,4,4a,5,6,8a-octahydronaphthalene-4a-carbonitrile (14), possibly due to neighboring group participation of the cyano function in the epoxidation step. Subsequent hydrogenation of the allylic double bond with palladium on carbon as catalyst, followed by reduction of the nitrile group with DIBAL-H afforded (4aR*,8aR*)-8a-(aminomethyl)-1,1-dimethyldecahydronaphthalen-4a-ol (16), which was deaminated with hydroxylamine-O-sulfonic acid to afford the target compound 4 that possesses an interesting woody odor with green-mossy, camphoraceous, and patchouli-type facets.