Stereoselective synthesis of unsaturated C-18 hydroxy fatty acids the self defensive substances

Rao, A. V. Rama; Reddy, E. R.; Purandare, A. V.; Varaprasad, Ch.V.N.S.

doi:10.1016/s0040-4020(01)90314-x

Cited by 31 publications

(18 citation statements)

References 9 publications

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“…For the allylic oxidation of terminal double bonds in 1‐alkenes to 1‐alkene‐3‐ones a number of oxidants are described. These are SeO 2 / tert ‐BuOOH , SeO 2 [S1, S = supporting information], NBS/CaCO 3 [S2], CrO 3 /HOAc/Ac 2 O [S3], CrO 3 · 2Pyr [S4], CrO 3 /dimethylpyrazole[S5], pyridinium dichromate/ tert‐ BuOOH [S6], Na 2 CrO 4 /HOAc/Ac 2 O [S7], CrO 3 (cat. )/ tert‐ BuOOH [S8], Cr(CO) 6 (cat.…”

Section: Resultsmentioning

confidence: 99%

“…Very promising appeared the oxidation with Cr(VI)‐montmorillonite (cat. )/ tert‐ BuOOH [S10] and the oxidation with SeO 2 / tert ‐BuOOH . The first reagent led to high yields of enones with terminal double bonds in shorter and unsubstituted olefins as in 1‐hexene, 1‐heptene and 1‐decene .…”

Section: Resultsmentioning

confidence: 99%

“…Methyl 9‐hydroxy‐10‐undecenoate ( 5 ): R f ‐value: 0.24 (petroleum ether/diethyl ether = 5:2).‐ 1 H NMR (CDCl 3 ): δ (ppm) = 1.24 (m, 8H, CH 2 ), 1.44 (m, 2H, C H 2 CH(OH)), 1.53 (m, 2H, C H 2 CH 2 CO), 2.23 (t, J = 7.5 Hz, 2H, CH 2 CO), 3.59 (s, 3H, OCH 3 ), 4.02 (m, 1H, C H (OH)), 5.02 (ddd as dt, J = 1.3 Hz, J cis = 10.6 Hz, 1H, CHC H a H b ), 5.14 (ddd as dt, J = 1.5 Hz, J cis = 17.2 Hz, 1H, CHCH a H b ), 5.79 (ddd, J = 6.3 Hz, J cis = 10.6 Hz, J trans = 17.2 Hz, 1H, CHCH).‐ The spectroscopic data agree well with those in ref. .…”

Section: Methodsmentioning

confidence: 99%

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Allylic oxidation of methyl 10‐undecenoate and nucleophilic additions to methyl 9‐oxo‐10‐undecenoate

Hinkamp

Schäfer

2014

Euro J Lipid Sci & Tech

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Methyl 10-undecenoate (2b) has been oxidized with tert-butyl hydroperoxide/selenium dioxide and potassium dichromate to 53% of methyl 9-oxo-10-undecenoate (4). Based on the conversion of 2b, the yield of 4 is 81%. Residual selenium in ester 5 was determined to be less than 1 ppm. The electrophilic double bond in enone 4 reacts in good to excellent yield with a variety of nucleophiles. With dimethyl malonate, acetylacetone, and methyl acetoacetate Michael-adducts at C-11 of enone 4 were obtained in 88-99% yield. Corresponding additions were achieved with nitroethane, 1-and 2-nitropropane in 78-89% yield. In a Nef-reaction some nitroalkyl adducts were converted to methyl esters of 9,12-dioxofatty acids in 99% yield. In methanol/sodium methoxide the ester methyl 11-methoxy-9-oxoundecanoate was obtained in 86% yield from enone 4. In a three step reaction with ammonium chloride/sodium cyanide, hydrochloric acid/acetic acid, and methanol/2,2-dimethoxypropane the ester 4 yielded 63% of dimethyl 4-oxo-dodecanedioate. With the cyanide ion the electrophilic carbon atom in aldehydes can be converted into a nucleophile (Stetter-reaction). Catalysed by sodium cyanide in DMF aromatic and heteroaromatic aldehydes RCHO with R ¼ phenyl, 2-thienyl, 2-furyl and 3-pyridyl were added to enone 4 to afford methyl 12-aryl-and methyl 12-heteroaryl-9,12-dioxododecanoates in 54-73% yield.Practical applications: The prepared oleochemicals are useful as precursors for pharmaceuticals and as monomers for polyesters and polyamides. They also may be applied to synthesize fatty acid conjugates by providing suitable connectors for biological active compounds and to attach groups with suitable physical properties for materials.

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Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

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Allylic oxidation of methyl 10‐undecenoate and nucleophilic additions to methyl 9‐oxo‐10‐undecenoate

Hinkamp

Schäfer

2014

Euro J Lipid Sci & Tech

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“…In our preliminary communication,13 we described that the intermolecular PKR of (silyloxymethyl)alkynes with ethylene was completely regioselective, giving cyclopentenones with the silyloxymethyl group in the β‐position 14. The precursors of 16‐B 1 ‐PhytoP and PGB 1 , internal alkynes 3a and 3b , respectively, were synthesized from propargyl alcohol according to the procedure shown in Scheme 13,15. The precursor of 9‐L 1 ‐PhytoP, alkyne 3c , was prepared from commercially available pent‐3‐yn‐1‐ol by simple protection as its tert ‐butyldimethylsilyl (TBS) ether (94 % yield).…”

Section: Resultsmentioning

confidence: 99%

General Approach to Prostanes B₁ by Intermolecular Pauson–Khand Reaction: Syntheses of Methyl Esters of Prostaglandin B₁ and Phytoprostanes 16‐B₁‐PhytoP and 9‐L₁‐PhytoP

Vázquez-Romero

Riéra

2013

Eur J Org Chem

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A synthetic approach to the methyl esters of Prostaglandin B1 and Phytoprostanes 16‐B1‐PhytoP (PPB1‐I) and 9‐L1‐PhytoP (PPB1‐II) based on the modified Julia olefination of a formylcyclopentenone and an appropriately protected hydroxy sulfone has been developed. The cyclopentenones were efficiently prepared by intermolecular Pauson–Khand reaction of a (silyloxymethyl)alkyne. The sulfone counterpart was prepared by regioselective ring‐opening of the appropriate chiral epoxides by 2‐mercaptobenzothiazole. The protecting group for the alcohol functionality on the sulfone proved to be crucial. Protection as a tert‐butyl ether was the best solution, giving better results than a tert‐butyldimethylsilyl ether.

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“…23 Both routes led to valuable intermediates, i.e. racemic mixture of 9-hydroxy-10-undecenoic acid ((±)- 1 ) as well as its methyl ester ((±)- 2 ), for the characterization of the enzymatic product.…”

Section: Methodsmentioning

confidence: 99%

Regio- and stereoselective hydroxylation of 10-undecenoic acid with a light-driven P450 BM3 biocatalyst yielding a valuable synthon for natural product synthesis

Kato

Nguyen

Gonzalez

et al. 2014

Bioorganic & Medicinal Chemistry

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We report herein the selective hydroxylation of 10-undecenoic acid with a light-activated hybrid P450 BM3 enzyme. Under previously developed photocatalytic reaction conditions, only a monohydroxylated product is detected by gas chromatography. Hydroxylation occurs exclusively at the allylic position as confirmed from a synthesized authentic standard. Investigation into the stereochemistry of the reaction indicates that the R enantiomer is obtained in 85% ee. The (R)-9-hydroxy-10-undecenoic acid obtained enzymatically is a valuable synthon en route to various natural products further expanding the light-activated P450 BM3 biocatalysis and highlighting the advantages over traditional methods.

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Stereoselective synthesis of unsaturated C-18 hydroxy fatty acids the self defensive substances

Cited by 31 publications

References 9 publications

Allylic oxidation of methyl 10‐undecenoate and nucleophilic additions to methyl 9‐oxo‐10‐undecenoate

Allylic oxidation of methyl 10‐undecenoate and nucleophilic additions to methyl 9‐oxo‐10‐undecenoate

General Approach to Prostanes B₁ by Intermolecular Pauson–Khand Reaction: Syntheses of Methyl Esters of Prostaglandin B₁ and Phytoprostanes 16‐B₁‐PhytoP and 9‐L₁‐PhytoP

Regio- and stereoselective hydroxylation of 10-undecenoic acid with a light-driven P450 BM3 biocatalyst yielding a valuable synthon for natural product synthesis

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Stereoselective synthesis of unsaturated C-18 hydroxy fatty acids the self defensive substances

Cited by 31 publications

References 9 publications

Allylic oxidation of methyl 10‐undecenoate and nucleophilic additions to methyl 9‐oxo‐10‐undecenoate

Allylic oxidation of methyl 10‐undecenoate and nucleophilic additions to methyl 9‐oxo‐10‐undecenoate

General Approach to Prostanes B1 by Intermolecular Pauson–Khand Reaction: Syntheses of Methyl Esters of Prostaglandin B1 and Phytoprostanes 16‐B1‐PhytoP and 9‐L1‐PhytoP

Regio- and stereoselective hydroxylation of 10-undecenoic acid with a light-driven P450 BM3 biocatalyst yielding a valuable synthon for natural product synthesis

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General Approach to Prostanes B₁ by Intermolecular Pauson–Khand Reaction: Syntheses of Methyl Esters of Prostaglandin B₁ and Phytoprostanes 16‐B₁‐PhytoP and 9‐L₁‐PhytoP