Linalool oxide dehydrated

A dehydrated linalool oxide, 2-methyl-2-vinyl-5-isopropenyltetrahydrofuran [13679-86-2], occurs naturally it has a minty eucalyptol odor and is used in perfumery. 

The linalool oxides (109) are probably the oldest known of this group (Vol. 2, p. 165). They have been isolated after the action of Streptomyces albus on linalool (28), the optical activity at C-2 of the furan is the same as that of the starting linalool. This work also points out that rotations of the linalool oxides are different when measured neat or in solution. The oxidized linalool oxide 889 has been found in grape juice. It was synthesized by the action of silver carbonate on the dihydroxylinalool 108 (also occurring in grape juice), and dehydrating the hemiacetals 890 thus formed. ... 

There are many compounds closely related to natural products that are associated with novel syntheses. Dehydrated linalool oxide 891, for example, is conveniently made by chlorination of linalool acetate (28 acetate) with calcium hypochlorite, then cyclization of the allyl chloride 892 with sodium hydroxide and Aliquat 336 in methanol. Once obtained 891 was converted to the dehydrogenated lilac alcohols 893 (R = H). The monoepoxides (on the isopropenyl group) were transformed in a mixture of diacetates that were pyrolyzed to the acetates 893 (R = Ac). Linalool oxide epoxides (894) have... 

Numerous other ethers containing pyran or furan rings are formed by the dehydration of aliphatic diols (e.g. linalool oxides, rose oxide or nerol oxide) and are components of many essential oils. For example, the furanoid 2R,5R)- E)- and (2J ,5S)-... 

The 2,3-dihydro-5-methylfuran species is formed in the atmosphere at low humidity via the cyclization and subsequent dehydration of 5-hydroxy-2-pentanone, itself an important product in the oxidation of pentane (Martin et al., 2002). Similar species are expected to be formed in the oxidation of other alkanes (C4 and larger), when isomerization of the initially formed alkoxy radical is of importance. Similarly, the species 5-methyl-5-vinyl-tetrahydrofuran-2-ol is a by-product of linalool oxidation, formed via the cyclization of an initially formed unsaturated hydroxycarbonyl species (Calogirou et al., 1999). The available data are summarized in table III-E-30. 

Ohloff et al. have synthesized the optically active nerol oxides (914A and 914B) from (- )-(R)-linalool [(R)-28] following the route in Scheme 70. In the last step, dehydration with phosphorous oxychloride in pyridine, some of the exocyclic isomers 915 were produced. Reduction of the nerol oxides (914) and the isomers 915 to rose oxide (909) were mentioned in Vol. 4 (p. 565, Refs. 123 and 773), and some specific conditions to furnish a maximum of the cis-isomer of 909 from 915 have been given, the cw-isomer being the more powerful smelling. ... 

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