245. Zur Kenntnis ätherischer Öle 5. Mitteilung [1] Zwei Monoterpenoxide aus dem sog. «destillierten» Limetten‐Öl (Citrus medica L., var. Acida Brandis; Citrus aurantifolia Swingle)

Abstract

Volumen 49, Fasciculus 7 (1966)

Two Complementary Synthetic Approaches to the Enantiomeric Forms of the Chiral Building Block (2,6,6-Trimethyltetrahydro-2H-pyran-2-yl)methanol: Application to the Stereospecific Preparation of the Natural Flavor Linaloyl Oxide

“…As mentioned in the introduction, this monoterpene is a relevant fragrance/flavor ingredient [43]. More specifically, it is one of the fragrance components of geranium and lime essential oil [7,8] and is a trace component of the flavor of many fruits or other vegetal species [9][10][11][12][13][14][15][16][17][18][19][20]. Since an effective and cheap synthesis of racemic 4 was established [44], linaloyl oxide is currently produced and commercialized in this form, under the trade name Limetol ® (Givaudan).…”

“…We are not aware of any olfactory evaluation of the single enantiomeric forms of this monoterpene that seems to occur in essential oils in nearly racemic form [8]. Since the organoleptic evaluation of this compound is subject to the availability of both (R) and (S) isomers in high enantiomeric purity, their stereoselective synthesis is highly desired.…”

“…Although a number of pyranoid derivatives possessing these structural frameworks were identified in nature, only few stereoselective approaches to their synthesis are described so far. For example linaloyl oxide (Compound 4) enantiomers ( Figure 2) are relevant flavor and fragrance components [7][8][9][10][11][12][13][14][15][16][17][18][19][20], sydowic acid (Compound 5) is a bioactive sesquiterpene produced by the mold Aspergillus sidowii [21], the diterpenic diol (Compound 6) was isolated from the African plant Anisopappus pinnatifidus [22], and triterpene panaxadiol (Compound 7) is a bioactive component of the ginseng extract [23]. These terpenes share in common the same tetrahydropyranyl moiety which contains a quaternary stereocenter, whose stereoselective construction is especially demanding.…”

75 Jahre Riechstoff‐ und Aroma‐Chemie im Spiegel der Helvetica Chimica Acta. Teil I

“…I # ) [125]. Bis auf zwei neue cyclische Ether [126] bestanden die ubrigen 42 Komponenten des atherischen Ols, die 97,6 YO aller fliichtigen Anteile ausmachen, aus bekannten monoterpenoiden Verbindungen. Allerdings verbleiben in den 2,4 % unaufgeklarter Verbindungen noch uber 100 Substanzen.…”

“…Das nahezu racemische 2,6,6-Trimethyl-2-vinyltetrahydropyran (49), das bereits von Rupe und Lung synthetisiert worden war [83], wurde als Bestandteil des Limetten-01s aufgefunden [84]. [86] [87] verkniipft werden.…”