The regioselective tert-butyldimenthylsilylation of the 6′-hydroxyl group of lactose derivatives via their dibutylstannylene acetals

Glen, Angela; Leigh, David A.; Martin, Richard P.; Smart, John P.; Truscello, Ada

doi:10.1016/0008-6215(93)84143-t

Cited by 27 publications

(12 citation statements)

References 12 publications

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“…Leigh and co-workers achieved selective silylations of lactose derivatives via dibutylstannylene acetals. 376 In a similar way to the glycosylation reactions described in section 9.2.1, the use of a bulky silicon-based electrophile led to a selective reaction at the more sterically accessible 6'-OH group of 287, rather than the 3′-position, the preferred site of reaction with acyl and alkyl halides (Scheme 105). An example of selective silylation of the secondary position of a stannylene acetal was reported by Garegg and co-workers, who accomplished the TBS protection of benzylidene-protected manno-pyranoside 141 by condensation with dibutyltin oxide, followed by treatment with TBSCl in DMF.…”

Section: Reagent-controlled Silylationmentioning

confidence: 92%

“…Stannylene acetal methodology (see section ) has been employed to achieve site-selective silylations of carbohydrate derivatives. Leigh and co-workers achieved selective silylations of lactose derivatives via dibutylstannylene acetals . In a similar way to the glycosylation reactions described in section , the use of a bulky silicon-based electrophile led to a selective reaction at the more sterically accessible 6’-OH group of 287 , rather than the 3′-position, the preferred site of reaction with acyl and alkyl halides (Scheme ).…”

Section: Silylationmentioning

confidence: 99%

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Site-Selective Functionalization of Hydroxyl Groups in Carbohydrate Derivatives

2018

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Methods for site-selective transformations of hydroxyl groups in carbohydrate derivatives are reviewed. The construction of oligosaccharides of defined connectivity hinges on such transformations, which are also needed for the preparation of modified or non-natural sugar derivatives, the installation of naturally occurring postglycosylation modifications, the selective labeling or conjugation of carbohydrate derivatives, and the preparation of therapeutic agents or research tools for glycobiology. The review begins with a discussion of intrinsic factors and processes that can influence selectivity in reactions of unprotected or partially protected carbohydrate derivatives, followed by a description of transformations that engage two OH groups in cyclic adducts (acetals, ketals, boronic esters, and related species). An overview of the various classes of site-selective transformations of OH groups in sugars is then provided: the reactions discussed include esterification, thiocarbonylation, alkylation, glycosylation, arylation, silylation, phosphorylation, sulfonylation, sulfation, and oxidation. Emphasis is placed on recently developed methods that employ reagent or catalyst control to achieve otherwise challenging transformations or site-selectivities.

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Section: Reagent-controlled Silylationmentioning

confidence: 92%

Section: Silylationmentioning

confidence: 99%

Site-Selective Functionalization of Hydroxyl Groups in Carbohydrate Derivatives

2018

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“…In these compounds, the azide tag replaces the 6′-OH group of the lactosyl moiety. Allyl lactoside 36 was selectively TBDMS-protected at this position via a stannane 59 followed by acetylation of the remaining hydroxy groups to produce intermediate 38. After desilylation, the 6′-OH group was mesylated and then substituted with sodium azide.…”

Section: ■ Results and Discussionmentioning

confidence: 99%

“…R f = 0.20 (DCM/MeOH 9:1); (38). To obtain a lactose derivative with an orthogonal protecting group at the 6′position, a procedure reported by Glen et al 59 was followed with modifications. Allyl lactoside 36 62 (12 g, 31.4 mmol) and dibutyltin(IV) oxide (7.97 g, 32 mmol) were dissolved in 700 mL dry MeOH and refluxed for 4 h. The mixture was evaporated under reduced pressure and dried thoroughly at vacuum.…”

Section: ■ Conclusionmentioning

confidence: 99%

Synthetic Glycosphingolipids for Live-Cell Labeling

et al. 2016

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Glycosphingolipids are an important component of cell membranes that are involved in many biological processes. Fluorescently labeled glycosphingolipids are frequently used to gain insight into their localization. However, the attachment of a fluorophore to the glycan part or-more commonly-to the lipid part of glycosphingolipids is known to alter the biophysical properties and can perturb the biological function of the probe. Presented here is the synthesis of novel glycosphingolipid probes with mono- and disaccharide head groups and ceramide moieties containing fatty acids of varying chain length (C4 to C20). These glycosphingolipids bear an azide or an alkyne group as chemical reporter to which a fluorophore can be attached through a bioorthogonal ligation reaction. The fluorescent tag and any linker connected to it can be chosen in a flexible manner. We demonstrate the suitability of the probes by selective visualization of the plasma membrane of living cells by confocal microscopy techniques. Whereas the derivatives with the shorter fatty acids can be directly applied to HEK 293T cells, the hydrophobic glycosphingolipids with longer fatty acids can be delivered to cells using fusogenic liposomes.

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“…A similar regioselectivity dependence on the size of the electrophile has been observed when unprotected lactosides are reacted in the presence of dibutyltin oxide. Allylation with allyl bromide gives the 3′‐ O ‐allylated product, while silylation with the more bulky tert ‐butyldimethylsilyl chloride affords exclusively the 6′‐ O ‐silylated compound 26…”

Section: Resultsmentioning

confidence: 99%

Stannylene‐Mediated Regioselective 6‐O‐Glycosylation of Unprotected Phenyl 1‐Thioglycopyranosides

Maggi

Madsen

2013

Eur J Org Chem

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A straightforward procedure is described for the synthesis of (1→6)‐linked saccharides by regioselective glycosylation of unprotected glycosyl acceptors. Phenyl 1‐thioglycopyranosides derived from D‐glucose, D‐galactose and D‐mannose were treated with dibutyltin oxide to introduce a stannylene acetal, and then subjected to selective glycosylation at the 6‐position with the Koenigs–Knorr protocol. Peracylated glycosyl bromides of D‐glucose, D‐galactose, D‐mannose and D‐glucosamine were employed as the donors to give the corresponding (1→6)‐linked disaccharides in moderate to good yields. The best results were obtained with glycosyl donors and acceptors derived from D‐glucose and D‐galactose. Fully acylated disaccharide thioglycosides could also serve as glycosyl donors for the regioselective coupling. Brominolysis and subsequent Koenigs–Knorr coupling with the stannylene acetal of phenyl 1‐thio‐β‐D‐glucopyranoside gave rise to the corresponding (1→6)‐linked trisaccharides in moderate yields.

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The regioselective tert-butyldimenthylsilylation of the 6′-hydroxyl group of lactose derivatives via their dibutylstannylene acetals

Cited by 27 publications

References 12 publications

Site-Selective Functionalization of Hydroxyl Groups in Carbohydrate Derivatives

Site-Selective Functionalization of Hydroxyl Groups in Carbohydrate Derivatives

Synthetic Glycosphingolipids for Live-Cell Labeling

Stannylene‐Mediated Regioselective 6‐O‐Glycosylation of Unprotected Phenyl 1‐Thioglycopyranosides

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