Reactions of dioxiranes with selected oleochemicals

Sonnet, Philip E.; Lankin, M. E.; McNeill, Gerald P.

doi:10.1007/bf02638900

Cited by 33 publications

(13 citation statements)

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“…The procedure of Sonnet et al (12) is followed: To 2 mmol of squalene in acetone is added 26 mmol of NaHCO 3 . Under vigorous stirring in the dark at ambient temperature, 5 mmol of Oxone ® dissolved in 6 mL distilled H 2 O is added dropwise in 1 h. Stirring is continued for 2 h after which water is added and the phases are separated.…”

Section: Methodsmentioning

confidence: 99%

The use of ¹H NMR for yield determination in the regioselective epoxidation of squalene

Aerts

Sels

Jacobs

2005

J Americ Oil Chem Soc

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1 H NMR can be used to determine the epoxide yield rapidly in the oxidation of squalene. Moreover, unequivocal distinction can be made between internal and terminal epoxide bonds. To underline the power of this technique, different stoichiometric and catalytic epoxidation procedures were carried out using squalene as substrate. They were characterized in terms of substrate conversion and regioselectivity of the epoxide fraction.Paper no. J10990 in JAOCS 82, 409-413 (June 2005).Besides the double bond epoxidation of fatty compounds (1), we became interested in the epoxidation of squalene and more specifically in the search for new catalytic regioselective epoxidation procedures for this compound. Squalene is a key intermediate in the biosynthesis of steroids such as lanosterol and cholesterol (2). The first step in this sequence consists of the formation of the terminal epoxide (2,3-oxidosqualene) by the squalene epoxidase enzyme (3). Although the synthetic production of this epoxide is unusually demanding owing to the similarity of the double bonds in the molecule, some authors have succeeded in the high-yield production of the terminal epoxide using N-bromosuccinimide (NBS) in a glyme/water solvent mixture followed by a base-catalyzed dehydrobromination (4,5). A great deal of research has been done on the driving force behind this unique regioselectivity. Although the first studies ascribed the selective formation of the terminal epoxide to a specific coiling of the squalene molecule, it is also accepted that the polarity of the oxidant plays a role in the product selectivity. Thus, the formation of both internal and terminal epoxides is associated with the ability of the oxidant to penetrate the coiled molecule. Charged or highly polarized oxidants such as NBS only affect the ends of the squalene molecule, yielding only the terminal epoxides. A third explanation for the highly selective NBS/glyme/water system (6) is based on the heat of formation of internal and terminal epoxides, which is reduced in the latter case by 5 kcal/mmol. During our research we encountered the problem of analysis. Because a facile analysis by GC is not possible, we screened the literature thoroughly. Surprisingly, only one procedure for the analysis of the epoxide isomers is reported (4). Although this method is widely applied, it is time-consuming and not very accurate. For example, the epoxide is first hydrolyzed to obtain the diol using aqueous perchloric acid. In a second step, the diol is quantitively converted into acetone and aldehydes. Finally, the terminal epoxide yield can be determined by measuring the amount of acetone present, whereas the internal epoxides are quantified based on the aldehydes. Nowadays, different types of NMR can be used to identify and characterize squalene and its epoxides. Although important work has been reported (7,8), no effort has been made to quantify the molar ratio of the internal vs. terminal epoxides when present in an isomeric mixture.In this article, we report the determination of the inter...

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Section: Methodsmentioning

confidence: 99%

The use of ¹H NMR for yield determination in the regioselective epoxidation of squalene

Aerts

Sels

Jacobs

2005

J Americ Oil Chem Soc

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“…Countless functionalizations of oleochemicals have already been implemented [5]. The carbon-carbon double bonds of fatty acids, fatty esters, and triglycerides have especially been converted into epoxy [6][7][8][9][10][11][12][13], hydroxyl [14][15][16][17][18][19][20][21], formyl [22][23][24][25][26][27], acrylate [28][29][30], or crossmetathesis derivatives [31][32][33], to name only a few. The functionalization of the carbon-carbon double bonds by amino groups is also of great interest.…”

Section: Introductionmentioning

confidence: 99%

Hydroaminomethylation of oleochemicals: A comprehensive overview

Vanbésien

Nôtre²,

Monflier

et al. 2017

Euro J Lipid Sci & Tech

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The present review explores the historical background of the rhodium-catalyzed hydroaminomethylation (HAM) of vegetable oils and the recent developments in this field. The reaction conditions are especially discussed and commented upon. Various amines have been grafted onto alkyl chains of vegetable oils, thus giving rise to a wide range of bio-based HAM-products. A focus is on bifunctional HAM-products as they have potential as monomers in polymer chemistry. The nature of the ligands stabilizing the rhodium catalytic species is also discussed. The catalytic results obtained with phosphanes and amines are analyzed and compared. The goal of this review is to convince the reader that HAM of vegetable oils is a simple and effective synthetic pathway to access valuable functionalized bio-based compounds with industrial potential.Practical applications: Products resulting from hydroaminomethylation of vegetable oils have potential as monomers in polymer chemistry and as bio-based surface-active agents.

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“…In our hands, this reagent and the conventional procedure generated two diastereomeric epoxyalcohols in a ratio of 3:2. Earlier, we reported the reactions of dimethyldioxirane (DMDO) and ethylmethyldioxirane (EMDO), generated with Oxone™, with methyl ricinoleate, as well as the ratios of the epoxidized alcohols that were produced by these and other dioxiranes (15). Because the dioxirane reaction procedure is simple and the reagents involved are quite inexpensive, we evaluated this reaction for preparing 2 as well as 4 in several complementary ways, namely, (i) Oxone™ without the added ketone that is normally used to generate a dioxirane, (ii) Oxone™-acetonechloroform as a two-phase system to generate and use DMDO, (iii) an acetone solution of DMDO prepared as described by Crandall et al (16), and (iv) Oxone™ in varying molar ratios to the homoallylic alcohol with 2-butanone as a cosolvent and source of EMDO in a two-phase reaction.…”

Section: Resultsmentioning

confidence: 99%

Selective oxidations of methyl ricinoleate: Diastereoselective epoxidation with titanium^IV catalysts

Foglia

Sonnet

Núñez

et al. 1998

J Americ Oil Chem Soc

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Conditions were developed for the selective epoxidation of the double bond of methyl ricinoleate (1) with ethylmethyldioxirane (EMDO) to give the homoallylic epoxyalcohol, methyl (Z)-9,10-oxido-12-hydroxyoctadecanoate (2) in high yields but in poor enantiomeric excess. The diastereomeric ratio for epoxyalcohol 2 was improved modestly when t-butylhydroperoxide, coupled with a titanium catalyst and a D-tartrate ligand, was used as oxidizing agent. Reaction of 1 with excess EMDO resulted in the concomitant epoxidation of the double bond and oxidation of the hydroxy group of 1 to give methyl (Z)-9,10-oxido-12-oxo-octadecanoate (4), along with methyl 8-(5-hexylfuran-2-yl)octanoate (5). Alternatively, ketoepoxide 4 was prepared by dioxirane oxidation of methyl 12-oxo-(Z)-9-octadecene (3) or by treating epoxyalcohol 2 with sodium hypochlorite. The ketoepoxide 4 is acid-labile and rearranges with loss of water to give furan 5 in high yield. JAOCS 75, 601-607 (1998). FIG. 2. (A) Proposed acid-catalyzed rearrangement pathway for ketoepoxide 4 to furan 5 through intermediate 6. (B) Mass spectrum for silylated dihydrofuran intermediate 6.

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Reactions of dioxiranes with selected oleochemicals

Cited by 33 publications

References 20 publications

The use of ¹H NMR for yield determination in the regioselective epoxidation of squalene

The use of ¹H NMR for yield determination in the regioselective epoxidation of squalene

Hydroaminomethylation of oleochemicals: A comprehensive overview

Selective oxidations of methyl ricinoleate: Diastereoselective epoxidation with titanium^IV catalysts

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Reactions of dioxiranes with selected oleochemicals

Cited by 33 publications

References 20 publications

The use of 1H NMR for yield determination in the regioselective epoxidation of squalene

The use of 1H NMR for yield determination in the regioselective epoxidation of squalene

Hydroaminomethylation of oleochemicals: A comprehensive overview

Selective oxidations of methyl ricinoleate: Diastereoselective epoxidation with titaniumIV catalysts

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The use of ¹H NMR for yield determination in the regioselective epoxidation of squalene

The use of ¹H NMR for yield determination in the regioselective epoxidation of squalene

Selective oxidations of methyl ricinoleate: Diastereoselective epoxidation with titanium^IV catalysts