Stereoselective synthesis of (R)- and (S)-Ipsdienols, pheromone components of bark beetles of the Ips family

Kovalenko, V. N.; Matyushenkov, E. A.

doi:10.1134/s1070428012090035

Cited by 8 publications

(9 citation statements)

References 9 publications

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“…Often, the resolution of enantiomers by crystallization compares favorably with other separation techniques due to better robustness and scalability, and high purity of final products. Following our successful experience, we have chosen this approach toward verbenol. The only known report on the enantioenrichment of cis ‐verbenol was published by Mori in 1976 .…”

Section: Resultsmentioning

confidence: 99%

Practical method for increasing optical purity of cis‐verbenol

2019

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R/S mixture of monoterpene alcohol cis-verbenol can be separated in preparative scale by its conversion into phthalic mono-ester and subsequent crystallization of its diastereomeric salts with (R)-α-methylbenzylamine and (S)-α-methylbenzylamine. Finally, basic methanolysis of the resolved phthalic mono-esters results (S)-cis-verbenol and (R)-cis-verbenol in high enantiomeric and diastereomeric purity.

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Section: Resultsmentioning

confidence: 99%

Practical method for increasing optical purity of cis‐verbenol

2019

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“…Due to its easy availability, 1‐phenylamine is one of the widely used amines applied for resolving racemic mixtures of chiral acids into enantiomers. It has been used, for example, to obtain insect pheromones, as well as some drug substances in enantiomerically pure form. In the present study, we propose a method for resolving racemic mixtures of both endo ‐ and exo ‐monoesters of trans ‐norborn‐5‐ene‐2,3‐dicarboxylic acid in the form of their salts with ( R )‐ and ( S )‐1‐phenylethylamine ( (R)-1 and (S)-1 ).…”

Section: Resultsmentioning

confidence: 99%

A Simple Method for Resolution ofEndo‐/Exo‐Monoesters ofTrans‐Norborn‐5‐Ene‐2,3‐Dicarboxylic Acids Into Their Enantiomers

Kovalenko

Kozyrkov

2014

Chirality

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Separation of optical isomers obtainable from trans-norborn-5-ene-2,3-dicarboxylic acid methyl and tert-butyl monoesters was performed by crystallization of the respective salts prepared with (R)- and (S)-1-phenylethylamine. Starting from racemic endo-monomethyl ester of trans-norborn-5-ene-2,3-dicarboxylic acid, prepared by partial hydrolysis of the cyclopentadiene-dimethyl fumarate adduct, the corresponding (2R,3R)-endo-monoester was isolated in 97% enantiomeric excess (ee) yield after seven repeated crystallizations from tetrachloromethane. Starting from exo-mono-tert-butyl ester of the same acid, prepared by alcoholysis of the cyclopentadiene-maleic anhydride adduct followed by isomerization, (2R,3R)-exo-monoester was isolated in >98% ee yield after four repeated crystallizations from ethanol. Crystallization of the acids from the mother liquor containing (S)-1-phenylethylamine yielded products with inverse stereochemical configuration.

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“…Yield 17.1 g (70%). Spectral characteristics and the angle of optical rotation of compounds obtained coincided with the previously measured data [1].…”

Section: (4s)-2-methyl-6-methylideneocta-27-dien-4-ol [(S)-ipsdienolmentioning

confidence: 91%

“…To the obtained solution of potassium tert-butylate heated at 75°С at vigorous stirring was added within 10 min a solution of 54.0 g (0.160 mol) of acid phthalate (S)-2 [1] in 50 g of anhydrous tert-butyl alcohol. After adding all the substance the mixture was boiled for 5 min at stirring and afterwards the reaction mixture was quickly cooled to the room temperature (20°С).…”

Section: (4s)-2-methyl-6-methylideneocta-27-dien-4-ol [(S)-ipsdienolmentioning

confidence: 99%

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Improved synthesis of optically active ipsdienol

Kovalenko

Prokhorevich

2016

Russ J Org Chem

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SHORT COMMUNICATIONSIn our preceding publication [1] a simple procedure was described for the preparation of both enantiomers of monoterpene alcohol ipsdienol 1, an actual pheromone component of bark beetle of genus Ips. The key synthesis stage was the resolution of the direct precursor of the ipsdienol, (±)-6-methyl-2-(2-chloroethyl)hepta-1,5-dien-4-ol by its conversion into acid phthalate and the crystallization of the acid phthalate as salt with (+)-or (-)-1-phenylethylamine. Then the optically active acid phthalates (S)-2 and (R)-2 were treated with potassium tert-butylate in tertbutyl alcohol. By the dehydrochlorination and the simultaneous alcoholysis of the ester moiety in one stage (S)-or (R)-ipsdienol was obtained in a 55% yield.The necessity of preparation of a large amount of optically active ipsdienol (S)-1 required a detailed study of the reaction between acid phthalate (S)-2 and potassium tert-butylate, since the reaction proceeded with a reproducible yield about 50%. In the initial procedure [1] a large amount of solvent and an essential excess of the base were required. In the reaction mixture a large quantity of unreacted acid phthalate of ipsdienol was present. The increase in the reaction dura-tion from 1 to 3 h and the use of more concentrated 20% solution of potassium tert-butylate not only did not increase the yield of ipsdienol (S)-1, but even resulted in a consi-derable decrease in its enantiomeric purity. In various expe-riments we observed unexpected and undesirable decrease in the enantiomeric excess of ipsdienol (S)-1 to 75-80% (Scheme 1).The heterolysis of esters of the optically active allylic alcohols at the O-R bond ( where R is the residue of the allylic alcohol) and the accompanying rearrangements with the migration of the double bond and the racemization along the S N 1 mechanism are studied in sufficient detail and have been discussed before [2][3][4][5]. These transformations were mostly studied by an example of acid phthalates which were used for resolution of the corresponding allylic alcohols into individual enantiomers. It was established by this research that the heterolysis of esters with the formation of allylic carbocations is sharply accelerated at higher temperature, but the optically active allylic alcohols proper do not suffer

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Stereoselective synthesis of (R)- and (S)-Ipsdienols, pheromone components of bark beetles of the Ips family

Cited by 8 publications

References 9 publications

Practical method for increasing optical purity of cis‐verbenol

Practical method for increasing optical purity of cis‐verbenol

A Simple Method for Resolution ofEndo‐/Exo‐Monoesters ofTrans‐Norborn‐5‐Ene‐2,3‐Dicarboxylic Acids Into Their Enantiomers

Improved synthesis of optically active ipsdienol

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