Geranyl acetate synthesis

Chulalaksananukul, W. Condoret, J. S. Combes, D. Geranyl Acetate Synthesis by Lipase-Catalyzed Transesterification in Supercritical Carbon Dioxide. Enzyme Microb. Technol. 1993, 15, 691-698. 

W Chulalaksananukul, JS Condoret, D Combes. Kinetics of geranyl acetate synthesis by lipase-catalyzed transesterification in n-hexane. Enz Microb Techn 14 293-297, 1992. 

Synthesis from (3-Pinene. Pyrolysis of /3-pinene yields myrcene, which is converted into a mixture of predominantly geranyl, neryl, and linalyl chloride by addition of hydrogen chloride in the presence of small amounts of catalyst, e.g., copper(I) chloride and an organic quaternary ammonium salt [29]. After removal of the catalyst, the mixture is reacted with sodium acetate in the presence of a nitrogen base (e.g., triethylamine) and converted to geranyl acetate, neryl acetate, and a small amount of linalyl acetate [30]. 

Synthesis of geranyl acetate by transesterification of propyl acetate with geraniol... 

The possible legioselecdvity and the preference for ( )>aUylic alcohol Hxxluction using the reoxida tive modification are demonstrated in a projected synthesis of cembranolides (equation 10). The substrate in this case contains two double bo and several allylic positions. This oxidation is reported to be even more selective than the aiudogous oxidation of geranyl acetate originally reported by Sh less. 

Oxidation reactions of this nature are common in the literature. For example, selenium dioxide in refluxing etiumolic solution brought about the allylic oxidative rearrangement geranyl acetate, which was further functionalized in a synthesis of the norsesquiterpenoid gytinidal (equation 46). This trans formation was also used in a total synthesis of phytol. Similarly, an a, -unsaturated aldehyde was obtained undm similar conditions in studies of a synthesis of pentalenic acid derivatives (equation 47). ... 

AllyUc oxidation. The reaction was used by Meinwald and co-workers in the first step of a synthesis of gyrinidal (9), a norsesquiterpenoid from gyrinid beetles, from geranyl acetate (5). 

N,N-Diethy1gerany1am1ne is a key intermediate for the synthesis of Industrially Important acyclic monoterpenes such as geranyl acetate, llnalooicitral and cltronellal... 

A Cfi + C4 synthesis of citral (32) dunethyl acetal consisted of the addition of the copper-lithium compound corresponding to 20 with the acetylenic acetal 60. The reaction occurred at - 35°C in 1 hour, and yielded the pure ( )-isomer in 92% yield. Another rather long syndiesis involved addition of the lithium derivative corresponding to 20 with 3,4-dichloro-2-butanone. Three conventional steps from die product of this Grignard reaction gave geranyl acetate (25 acetate). ... 

Stereocontrolled synthesis of ( )-JH II is shown in Figure 3.5.20 Coupling of phenyl sulfide A with bromide C, prepared from geranyl acetate B, gave D. Then, D was converted to ( )-JH II (62).20... 

Karahana ether (196), isolated from Japanese hops, is also a 1,1,2,3-tetra-methylcyclohexane derivative, and has been synthesised by Coates and Melvin by a route that they suggest may resemble the biogenetic pathway.Their synthesis consists in cyclising geranyl acetate (194) with benzoyl peroxide in the presence of cupric saltsand hydrolysing the resulting mixture to the corresponding diols, from which the cis-diol (195) is separated and converted to the ether with p-toluenesulphonyl chloride in pyridine at room temperature. 

A total synthesis of ethyl geranate (28) makes use of the addition of ethyl 4-bromo-3-methylbut-2-enoate (29) to the nickel carbonyl complex (30) of prenyl bromide. Geranyl acetate and the ethyl ether were made in a similar way. ... 

Japanese chemists have reported a stereoselective synthesis of humulene (9), an 11-membered cyclic sesquiterpene, by intramolecular a-alkylation of a keto group by a jr-allylpalladium complex. The starting material (7) was derived from geranyl acetate. In this case, the efficiency of the cyclization was markedly improved by addition of a diphosphine ligand such as l,3-bis(diphenylphosphino)-... 

For the synthesis of sarcinaxanthin (441) in racemic form a biomimetic, acid-promoted prenylation reaction has been described. The key step was the alkylation-cyclization of geranyl acetate (214) with the isoprene epoxide 215 to give, in a mixture, 216 with the desired 2,6-cw-stereochemistry. The primary alcohol group was transformed to the corresponding mesylate which was dehydrated and subsequent hydrolysis gave 217. Conversion of 217 into the sulphone 218 was achieved by preparation of the corresponding mesylate, followed by... 

For the synthesis of aleuriaxanthin (81), geranyl acetate (1) was chosen as starting material. Oxidation of a terminal methyl group with Se02, followed by reduction, gave the allylic alcohol 2 which was subjected to a Sharpless epoxidation to give the epoxide J in a yield of 68% [1] (Scheme 3). 

In the 1980s, the Japanese firm Kuraray developed a stereoselective Vitamin A synthesis, which follows the Cm + Cm concept. The synthetic building blocks are cyclogeranyl phenyl sulfone and a Cm-aldehyde, which is obtainable by allylic oxidation of geranyl acetate with t-butyl hydroperoxide. [81] The alcohol function is protected as the THP-ether, and the sulfmic acid and hydroxytetrahydro-pyran are eliminated with potassium fbutoxide in petroleum ether. By means of this double elimination, the reduction step is avoided. 

A new synthesis of geranyl acetate (142) has been described but a very convenient approach is to simply stir an ethyl acetate... 

Corey showed that allyl fragments could be coupled by treating the allyl halides with Ni(CO)4. Unsymmetric coupling is possible if the Tr-allyl nickel halide from the first allyl halide addition is isolated and allowed to react with the second allyl halide. Equation 14.59 shows the synthesis of geranyl acetate by this procedure. 

We present here some significant examples in cyclization using Pd-catalyzed allyla-tion, in carbocycle and macrolide chemistry. Humulene, a fundamental monocyclic sesquiterpene, is derived biologically from famesol by anti-Markownikov cyclization no synthesis of this terpene by such cyclization had been realized before the highly stereoselective synthesis presented by Yamamoto and co-workers. The acyclic sesquiterpene skeleton was constructed starting with geranyl acetate via the ( ,ii)-bromide 316, which... 

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