A-Santalol

The piincipal component, t7t-a-santalol (65), has contioveisial odoi piopeities t7t-P-santalol (66) contributes most to the odor of sandalwood. A number of trace constituents have been characterized, two of which (76) [59300-43-5J and (77) [63569-02-8] ate worthy of mention for their very clean sandalwood notes (38). 

OC-Santalol. Sandalwood oil is comprised of mainly (90%) a- and P-santalol, which gives the oil the woody, tenacious sandalwood odor. An impure a-santalol [115-71 -9] (100) can be isolated by the distillation of the oil. P-Santalol [77-42-9] (101) is also isolated but ia much smaller amounts. The price of sandalwood oil, E. Indian, ia 1995 was 286/kg, and the oil from Indonesia was 187/kg (69). The high price of these oils has created the need to synthesize new materials with the sandalwood odor. The terpenophenols are manufactured by condensation of camphene with phenoHc compounds followed by hydrogenation to the cycloaUphatic alcohols (194). 

There exist in sandalwood oil (from Santalum album) two isomeric sesquiterpene alcohols, of the formula CjjHg O. They are both primary UDSaturated alcohols, one being bicyclic, the other tricyclic. These two alcohols are termed a-santalol and /3-santalol. a-santalol has the following characters —... 

The specific gravity, refractive index, and specific rotation given above are those recorded by Paolini and Divizia and are probably accurate since the a-santalol was prepared by regeneration from its strychnine phthalate. The values recorded for commercial santalol, prepared by fractional distillation, are as follows, and are the average values for the mixed santalols as they occur in sandalwood oil... 

Schimmel ves the following figures for a-santalol, but those of Paolini and Divizia are probably more accurate —... 

Figure 10.8 Total ion current chromatograms obtained after headspace SPME for (a) Kyphi and (b) B. sacra olibanum. Peak labels correspond to compound identification given in Table 10.3. The occurrence of isoincensole acetate (128) as well as the occur rence of the oxygenated sesquiterpene 98 and of dimer 2 (111) in Kyphi are clear fingerprints of the botanical origin of the olibanum used. Peaks labelled by letters correspond to the following compounds a, cinnamaldehyde b, vanilline c, curzerene d, furanoeudesma 1,3 diene e, a santalol f, 2 methoxyfuranodiene. Reproduced from S. Hamm, j. Bleton, j. Connan, A. Tchapla, Phytochemistry, 66, 1499 1514. Copyright 2005 Elsevier Limited...

Further studies on the biosynthesis of ovalicin (57) have demonstrated the use of deuterium magnetic resonance in biosynthetic studies. Compounds (59)—(62), structurally related to (-)-a-santalene (58), have been isolated from the essential oil of Lavandula ojficinalis and L. hybrida " An alternative synthesis of a-santalol... 

East Indian sandalwood oil consists almost exclusively of closely related sesquiterpenoids by far the main constituents are the alcohols a-santalol [115-71-9], 45-55%, and /3-santalol [77-42-9], 18-24%. Mainly responsible for the odor is /3-santalol. [261, 764-769]. 

Sandalwood, East Indian Santalum album L. (-l-)-a-Santalol (45-55), (-)-p-santalol (18-24)... 

Reaction with isoprene epoxide. Alkyllithium reagents undergo 1,4-addition to isoprene epoxide to give predominately (Z)-allylic alcohols, particularly in the presence of a base (equation I). The reaction was used to prepare a-santalol (I) from n-bromotricyclene. 

Tricyclenes. Benzenesulfenyl chloride reacts with 5-mcthylene-2-norbornene (1) to form the tricyclcnc derivative 2. This reaction was used to synthesize tricyclo-e a-santalol (3)1 and cyclosativene (4).2... 

As an example, when phenylpotassium is allowed to react with 8-bromonortricyclene, a-santalene is produced which is then submitted again to metallation with LIC-KOR followed by borylation and oxidation.76 The allowance for torsional equilibration produces the (Z)-a-santalol, one of the main constituents of the highly prized sandalwood oil, with no trace of the (A l-isomcr. The entire sequence can also be contracted to a one-flask protocol still giving quite acceptable yields.76... 

SYNS ARHEOL EAST INDIAN SANDALWOOD OIL FEMA No. 3006 OILS, SANDALWOOD OIL OF SANTAL SANTAL OIL a-SANTALOL (FCC)... 

In the course of developing stereospecific routes to trisubstituted double bonds, Corey et al. have completed an efficient synthesis of a-santalol (132), many stages of which involve recent synthetic techniques from Corey s laboratory. Thus (—)-7r-bromotricyclene (133) was converted into (134) by successive treatment with lithio-l-trimethylsilylpropyne, silver nitrate (desilylation), and potassium... 

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