Unsaturated carbohydrates. Part IX. Synthesis of 2,3-dideoxy-α-<scp>D</scp>-erythro-hex-2-enopyranosides from tri-O-acetyl-<scp>D</scp>-glucal

Ferrier, R. J.; Prasad, N.

doi:10.1039/j39690000570

Cited by 307 publications

(165 citation statements)

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“…The cyclopropanated diacetate 10 needed to furnish the desired substrate 8, was itself obtained via cyclopropanation (12) of the olefinic diacetate 11 (13). The conversion was only 27% effective judging from the n.m.r.…”

Section: Dideoxy-23-c-(exo-carbethoxy-c-methy1ene)-a-mentioning

confidence: 99%

The Synthesis of some α-Cyclopropylcarbonyl Glycopyranosides

Fraser‐Reid¹,

Carthy²

1972

Can. J. Chem.

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The syntheses of three a-cyclopropylcarbonyl compounds of carbohydrate origin, 1, 2, 3, are described. The cyclopropyl carboxaldehyde 1 was obtained from the corresponding carbinol by manganese dioxide oxidation of the primary alcohol. However, the secondary cyclopropyl alcohol in 8 did not respond to manganese dioxide and its oxidation (in the tritylated derivative (14), to the cyclopropyl ketone, 2, had to be achieved by ruthenium tetroxide. The sequence leading to 2 (via 8) began with ethyl 4,6-di-0-acetyl-2,3-dideoxy-a-D-erythro-hex-2-enopyranoside 11, which added methylene to give the a-D-a110 configuration with the cyclopropane ring syn to the glycosidic ethoxy group. The diastereomeric tritylated cyclopropyl ketone 3, possessing the cyclopropyl ring anti to the ethoxy group, resulted from cyclopropanation of the a/3-unsaturated ketone, 15. In the latter case, the acetoxy group apparently provides greater directing influence to the incoming methylene than does the allylic ethoxy group.Les syntheses de trois composts a-cyclopropylcarbonyles d'origine carbohydrate, 1, 2, 3 sont dtcrites. Le cyclopropyl carboxaldthyde 1 a t t t obtenu a partir du carbinol correspondant, par oxydation au dioxyde de manganese de I'alcool primaire. Cependant, le cyclopropylalcool secondaire dans 8 ne rtagit pas sur le dioxyde de manganese et son oxydation (dans le dtrivt tritylt 14) en cyclopropylcttone 2 a dti &tre effectute par le tttroxyde de ruthtnium. La stquence conduisant a 2 (via 8) commence avec I'tthyl di-0-acttyl-4,6 did6oxy-2,3-a-~-i.rythro hexeno-2 pyranoside 11, qui par addition de methylbne conduit a la configuration a-D-all0 avec le cycle cyclopropane en syn par rapport au groupe tthoxy glycosidique. La cyclopropylcttone tritylee diasttreoisomere 3, avec le cyclopropyl en anti par rapport au groupe tthoxy, rtsulte de la cyclopropanation de la cttone a/3 insaturee 15. Dans ce dernier cas, le groupe acttoxy oriente apparemment de faqon plus grande le methylene qui entre, que ne le fait le groupe tthoxy allylique.

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Section: Dideoxy-23-c-(exo-carbethoxy-c-methy1ene)-a-mentioning

confidence: 99%

The Synthesis of some α-Cyclopropylcarbonyl Glycopyranosides

Fraser‐Reid¹,

Carthy²

1972

Can. J. Chem.

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“…2 obtainable from the anomers, form a DL pair and are therefore indistinguishable by n.m.r. spectroscopy.…”

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confidence: 99%

An Apparent Stereochemical Effect in MnO₂ Oxidation of Some Allylic Alcohols

Fraser‐Reid¹,

Carthy²,

Holder³

et al. 1971

Can. J. Chem.

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3,4-Di-0-acetyl-D-xylal undergoes acid-catalyzed reaction with ethanol to give the anomeric mixture of ethyl 2,3-dideoxy-4-0-acetyl-~-glycero-pent-2-enopyranosides which can be separated after deacetylation.The a-D anomer 1 is readily oxidized by manganese dioxide to the a,p-unsaturated ketone but the p-D anomer 2 is inert. Thorough investigation of the 100 and 220 MHz n.m.r. spectra of 1 and 2, their acetates, and dinitrobenzoates indicates that each exists conformationally pure in the half-chair form having the benefit of the anomeric effect. Hence in the oxidizable anomer 1 the C-4 allylic hydroxyl group is pseudoequatorial; in the unoxidizable one it is pseudoaxial. Hydrogen bonding does not appear to be the reason for failure of 2 to oxidize.The ethoxy groups of 1 and 2 are found to be ABX, system with unusually large separation for the AB protons.Le di-O-acktyl-3,4-~-xylal soumis B une reaction acido-catalysee dans l'ethanol, donne un melange anomtrique de dideoxy-2,3-0-acetyl-4-D glyckro-pentene-2-pyranosides d'kthyle. L'isomere-a-D-1 est rapidement oxyde par le bioxyde de manganese en cetone or,p insaturee, par contre l'isornere P 2 est inerte. L'examen des composCs 1 et 2 iinsi que de leurs derives acetates et dinitrobenzoates, en r.m.n. 100 et 220 MHz a montrC que chacun des isomtres est exclusivement sous forme d'une dernie chaise gr%ce ii "l'effet anomkrique". Ainsi, I'isomere oxydC 1 possede line hydroxyle allylique en C-4 pseudo equatorial. Tandis que dans 2, le rn&me groupe est pseudo axial.Les groupes ethoxy dans 1 et 2 forrnent des systemes ABX, avec une separation inhabituellement grande des protons AB.Canadian Journal of Chemistry, 49,3038 (1971) In a recent publication from this laboratory (1) it was reported that when ethanol reacted with 3,4-di-0-acetyl-D-xylal under boron trifluoride catalysis (2) a mixture was produced which, after deacetylation, could be separated chromatographically into what appeared to be a-and P-anomers of ethyl 2,3-dideoxy-Dglycero-pent-2-enopyranoside. The faster running component l a behaved normally on manganese dioxide oxidation, being converted to an a,P-unsaturated ketone within 8 h. The slower running substance 2a, however, gave no evidence for ketone formation after 14 days of exposure to manganese dioxide.It seemed strange that l a and 2a would display such a difference in oxidizability if the only difference between both compounds was 'Undergraduate research participant, summer 1970. Department of Chemistry, University of Waterloo, Waterloo, Ontario. 2Revision received June 10, 1971. the orientation of the ethoxy group at the remote anomeric center. Both compounds characterized as their dinitrobenzoate esters l b and 2b respectively gave satisfactory microanalyses (3). As expected for an anomeric pair, both l a and 2a lost the aglycon readily (4) to give the same strong ion, 3, corresponding to M+-OCH,CH, at nz/e 99. Structure 4 which could also lead to ion 3 is excluded since 1 and 2 from their n.m.r. and i.r. spectra are not vinyl ethers. The speci...

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“…Tri-O-acetyl-D-glucal (1) was Ferrier-transformed 15 and deacetylated to give benzyl α-D-pseudoglucal (2). Selective protection of the 6-hydroxyl group of 2 with t-butyldiphenylsilyl chloride (TBDPSCl) produced compound 3.…”

Section: Resultsmentioning

confidence: 99%

Amidochlorination of 4-O-Azidoformyl-D-pseudoglycals with Iron (Ⅱ) Chloride and Chlorotrimethylsilane

2002

Bulletin of the Korean Chemical Society

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Unsaturated carbohydrates. Part IX. Synthesis of 2,3-dideoxy-α-D-erythro-hex-2-enopyranosides from tri-O-acetyl-D-glucal

Cited by 307 publications

References 0 publications

The Synthesis of some α-Cyclopropylcarbonyl Glycopyranosides

The Synthesis of some α-Cyclopropylcarbonyl Glycopyranosides

An Apparent Stereochemical Effect in MnO₂ Oxidation of Some Allylic Alcohols

Amidochlorination of 4-O-Azidoformyl-D-pseudoglycals with Iron (Ⅱ) Chloride and Chlorotrimethylsilane

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Unsaturated carbohydrates. Part IX. Synthesis of 2,3-dideoxy-α-D-erythro-hex-2-enopyranosides from tri-O-acetyl-D-glucal

Cited by 307 publications

References 0 publications

The Synthesis of some α-Cyclopropylcarbonyl Glycopyranosides

The Synthesis of some α-Cyclopropylcarbonyl Glycopyranosides

An Apparent Stereochemical Effect in MnO2 Oxidation of Some Allylic Alcohols

Amidochlorination of 4-O-Azidoformyl-D-pseudoglycals with Iron (Ⅱ) Chloride and Chlorotrimethylsilane

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An Apparent Stereochemical Effect in MnO₂ Oxidation of Some Allylic Alcohols