Linalyl oxide

Linalool, 3 231, 232, 233 24 477, 495, 496, 500-503, 546 acid treatment of, 24 502 epoxidation of, 24 502 main producers of, 24 501 Linalool oxide, 24 502 Linalyl, 24 479 Linalyl acetate, 24 501 Linalyl alcohol, 24 500 Linalyl esters, 3 231 Linalyl oxide, 24 503 Lincomycin, registered for use in aquaculture in Japan, 3 221t Lincosamide, bacterial resistance mechanisms, 3 32t Lindane, 13 145-147... 

Treatment of the selenide (19) with unbuffered 30% hydrogen peroxide-THF yields the cis- and trans-linalyl oxides (247) via [2,3] sigmatropic rearrangement. Kossanyi et al. have improved upon the efficiency of Vig s synthesis of the four lilac alcohols (248). The synthesis of the furanoid (249), formed during sulphuric acid-catalysed dimerization of isoprene, is straightforward. The known half-... 

Iodolactonization of y, o-unsaturated alcohols results in preferential formation of tram-2, 5-disubstituted tetrahydrofuranes. However, the corresponding benzyl ethers cyclize preferentially to the cis-isomers. The alkyl group must be bulky enough to exert a steric effect, but not to prevent cyclization. Substituted benzyl ethers are particularly useful. Examples of this steric control are illustrated for the preparation of tram- and c/s-linalyl oxide (equations I and II).10... 

Iodoetherification has been used in the synthesis of cis and trans linalyl oxides. Mechanistically, the rate of departure of the hydroxyl protecting group in the starting 7,8 unsaturated ether was found to be critical to the stereochemistry of the product.218 The alkyl group R (Scheme 47) must be sufficiently bulky as to... 

This cyclization can be used to prepare cii-linalyl oxide (2) in 70% overall yield from the benzyl ether 1. Under the same conditions, the correspionding free alcohol is converted into trans-2 in comptirable yield. ... 

Many hydroxylated linalools [including compounds 105, 106, 108, and 110, both (Z)- and ( )-isomers], as well as the epoxides of both furanoid (109) and pyranoid (see section on pyrans) linalyl oxides, have been identified in papaya fruit (Carica papaya). At the same time, the first reported occurrence of die two linalool epoxides (112) in nature was made. These epoxides are well known to be unstable and easily cyclized (see Vol. 2, p. 165) and have been made by careful peracid oxidation of linalool. An interesting new method has now been described. While the vanadium- or titanium-catalyzed epoxidation of geraniol (25) gave the 2,3-epoxide (see above), as does molybdenum-catalyzed epoxidation with hydrogen peroxide, the epoxidation of linalool (28) with molybdenum or tungsten peroxo complexes and hydrogen peroxide led, by reaction on the 6,7-double bond, to 112. ... 

The unsaturated pyran 931 has been identified in clary sage oil by Maurer and Hauser. They synthesized it by base-catalyzed elimination of the mesylate of pyranoid linalyl oxide 932. ° ... 

The full paper (Vol. 8, p. 58) on the biogenetic-type synthesis of the linalyl oxides has been published and dihydro-ocimenoyl oxide (230) has been synthesized by the regiospecific reaction of 2-methylbutanal with the y-carbon atom of a,a-dimethylallyltrimethylsilane catalysed by TiCU, presumably via cyclization of the corresponding y-chloro-alcohol. ° Straightforward syntheses of perillene (231 X = H,H) and egomaketone (231 X = O) involve prenylation... 

Phenols are more acidic than alcohols and therefore successful Pd-catalyzed allyla-tion of phenols with allylic carbonates is common (Table 3). The situation with alcohols is different since the acidity of the pronucleophile alcohol is similar to the acidity of methanol or ethanol. However, good intramolecular versions have been reported in syntheses of vinyltetrahydrofurans and of linalyl oxides. The use of carbonates of alkyl allyl alcohols in which the alkyl part is coherent with the pronucleophile is particularly successful, as shown in the remote asymmetric induction of Scheme 33. 

Thomas, A. F., and R. Dubini Terpenoids Derived from Linalyl Oxide. 3. The Isolation, Structure, Absolute Configuration and Synthesis of the Davanafurans, Nor-Sesquiterpenes Isolated from Artemisia pallens. Helv. Chim. Acta 57, 2006 (1974). 

Terpenoids Derived from Linalyl Oxide. 4. The Oxidation of Davanone. Isola-... 

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