Scope and Applications of "Active and Latent" Thioglycosyl Donors. Part 4

Cao, Suoding; Hernández-Matéo, Fernando; Roy, René

doi:10.1080/07328309808002341

Cited by 38 publications

(21 citation statements)

References 1 publication

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“…Often sugars of different reactivity and protecting group patterns as well as with different thiol aglycons are compared (11). p-NO 2 -Phenyl thioglycosides have been used as inert acceptors, but to function as donors they have to be activated by conversion of the nitro functionality into an acetamido group, and even then the donor capacity is limited except for neuraminic acid donors (22)(23)(24)(25). So far, the only report on orthogonal couplings between thioglycosides varying only in the aglycon functionality to give disaccharide donors was performed using steric effects by Boons et al (12).…”

Section: Resultsmentioning

confidence: 99%

Investigation of the reactivity difference between thioglycoside donors with variant aglycon parts

Lahmann¹,

Oscarson²

2002

Can. J. Chem.

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The reactivity of perbenzoylated thioglycosides with various thiol aglycons has been compared and quantified using competitive glycosylation experiments. Methyl 2,3,4-tri-O-benzyl-a-D-glucopyranoside was employed as acceptor and DMTST as a promoter. The reactivity was found, as expected, to depend on the electron donating properties of the aglycon. Hence, the most reactive donor, the cyclohexyl thioglycoside, was found to be about three times as reactive as the thioethyl glycoside, which in turn was twice as reactive as the thiomethyl donor. The thiophenyl donor was even less reactive, whereas p-halophenyl donors were inert under the glycosylation conditions used -but could be activated using NIS-TfOH as promoter. Furthermore, it was found that galactosyl donors were three to four times more reactive than the corresponding glucosyl derivative. These results allowed the design of an orthogonal coupling between thioglycosides with the same protecting groups (benzoyls) but with different thiol aglycons.Résumé : En se basant sur des expériences de glycosylations compétitives, on a comparé et quantifié la réactivité de thioglycosides perbenzoylés avec diverses thioaglycones. On a utilisé le 2,3,4-tri-O-benzyl-a-D-glucopyranoside de méthyle comme accepteur et le DMTST comme promoteur. On a trouvé, tel que prévu, que la réactivité dépend du caractère électrodonneur de l'aglycone. On a donc trouvé que le donneur le plus réactif, le thioglycoside de cyclohexyle, est trois fois plus réactif que le glycoside de thioéthyle qui est lui-même deux fois plus réactif que le donneur thiométhyle. Le donneur thiophényle est encore moins réactif alors que les donneurs p-halophényles sont inertes dans les conditions de glycosylation utilisées; ils peuvent toutefois être activés en utilisant le NIS-TfOH comme promoteur. De plus, on a trouvé que les donneurs galactosyles sont de trois à quatre fois plus réactifs que le dérivé glucosyle correspondant. Ces résultats ont permis de mettre au point un couplage orthogonal entre des thioglycosides avec les mêmes groupes protecteurs (benzoyles), mais des thioaglycones différentes.

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Section: Resultsmentioning

confidence: 99%

Investigation of the reactivity difference between thioglycoside donors with variant aglycon parts

Lahmann¹,

Oscarson²

2002

Can. J. Chem.

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“…In order to appreciate fully the flexibility of the "active-latent" glycosylation strategy introduced by us [22][23][24][25] When active-disarmed p-N-acetamidophenyl thioglycosyl donors 29 and 32 were treated with glycosyl acceptor 9 using only a catalytic amount of TfOH (0.2 equiv) in dichloromethane, no glycosylation products were observed. However, formation of disaccharides 30 (94%) and 35 (80%), respectively, were rapidly achieved in high yields when TfOH was present in equimolar amounts with respect to the thioglycosyl donor.…”

Section: Qualitative Evaluation Of Relative Reactivitiesmentioning

confidence: 99%

“…This concept has also led our group to disclose a novel extension of this notion to the aglycon residues of thioglycosyl donors [22][23][24][25]. This novel and complementary approach was coined "active-latent" because it permitted a temporarily inactive (inert/latent) thioglycosyl donor to be transformed, by a simple chemical process, into an active form.…”

Section: Introduction and Conceptmentioning

confidence: 95%

“Active–Latent” Thioglycosyl Donors and Acceptors in Oligosaccharide Syntheses

Shiao

Roy

2010

Reactivity Tuning in Oligosaccharide Assembly

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The fine tuning of thioglycosides used as glycosyl donors occurs through careful manipulations of the aglycon's nucleofugality, for example, by using "active-latent" principles. In the first section, the control of the relative leaving group abilities will be discussed in terms of electronic factors, including electron-donating/withdrawing substituents. In the second section, the nucleofugality will be adjusted by steric factors. Quantitative reactivity relationships will then be documented followed by presentation of other controlling elements including locked conformations, solvents, and promoters that will be illustrated throughout.

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“…SBizAn moieties allowed to execute the active-latent-like oligosaccharide synthesis, a strategy pioneered by Roy et al . [82, 83]. In ordinance with this methodology, the active SBiz donor 95 was glycosidated with the latent SBizAn acceptor 98 in the presence of methyl iodide to afford disaccharide 99 in 75% yield.…”

Section: S-benzimidazolyl Derivativesmentioning

confidence: 99%

Glycosyl thioimidates as versatile building blocks for organic synthesis

Hasty

Demchenko

2012

Chem Heterocycl Comp

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This review discusses the synthesis and application of glycosyl thioimidates in chemical glycosylation and oligosaccharide assembly. Although glycosyl thioimidates include a broad range of compounds, the discussion herein centers on S-benzothiazolyl (SBaz), S-benzoxazolyl (SBox), S-thiazolinyl (STaz), and S-benzimidazolyl (SBiz) glycosides. These heterocyclic moieties have recently emerged as excellent anomeric leaving groups that express unique characteristics for highly diastereoselective glycosylation and help to provide the streamlined access to oligosaccharides.

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Scope and Applications of "Active and Latent" Thioglycosyl Donors. Part 4

Cited by 38 publications

References 1 publication

Investigation of the reactivity difference between thioglycoside donors with variant aglycon parts

Investigation of the reactivity difference between thioglycoside donors with variant aglycon parts

“Active–Latent” Thioglycosyl Donors and Acceptors in Oligosaccharide Syntheses

Glycosyl thioimidates as versatile building blocks for organic synthesis

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