A Catalytic and Stereoselective Glycosylation withβ-Glycosyl Fluorides

Mukaiyama, Teruaki; Takeuchi, Kazuhiko; Jona, Hideki; Maeshima, Hisashi; Saitoh, Terunobu

doi:10.1002/1522-2675(20000809)83:8<1901::aid-hlca1901>3.0.co;2-q

Cited by 35 publications

(27 citation statements)

References 21 publications

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“…This can also explain why the consumption of glycosyl fluoride was much faster in glass vessels when weaker glycosyl nucleophiles ( Table 2, entries 5 and 7) were used as water simply outcompeted the 4-OH glycosyl nucleophile and resulted in trehalose formation. [25][26][27]31,[42][43][44][45][46] The effect of adding drying agents to this particular glycosylation seems highly important as Toshima has reported an increase in yield from 32 % to 99 % of the desired glycoside when 100 wt.-% 5Å molecular sieves were added. [25][26][27]31,[42][43][44][45][46] The effect of adding drying agents to this particular glycosylation seems highly important as Toshima has reported an increase in yield from 32 % to 99 % of the desired glycoside when 100 wt.-% 5Å molecular sieves were added.…”

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confidence: 99%

Vessel Effect in C–F Bond Activation Prompts Revised Mechanism and Reveals an Autocatalytic Glycosylation

et al. 2020

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Activation of C-F bonds under acidic conditions results in the formation of hydrogen fluoride as the reaction progresses. In the following communication, the effect of the vessel material on such reactions has been investigated and a significant difference between an HF-resistant material and common borosilicate glassware has been found. HF was found to react rapidly with borosilicate glassware, seemingly leaching fluoro- [a] 140 silicate into solution, but persisted in HF-resistant materials. Several examples of C-F bond activation on glycosyl fluorides and benzyl fluorides as well as NMR-studies suggest a significant effect of the choice of the reaction vessel, leading to the discovery of an autocatalytic glycosylation and a revised mechanism for the activation of benzyl fluorides, suggesting activation by SiF 4 rather than HF. Scheme 1. Examples of C-F bond activation promoted by acid-or H-bond catalysis and the work presented in this paper.

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confidence: 99%

Vessel Effect in C–F Bond Activation Prompts Revised Mechanism and Reveals an Autocatalytic Glycosylation

et al. 2020

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“…The desired azide‐bearing acceptor 8 and thioglycosilated donor 7b were prepared in excellent overall yields of 24 % over eleven steps and 33 % over ten steps, respectively. Subsequent glycosylation of donor 7b and acceptor 8 yielded the chitobiosyl azide 9 . Finally, repeating PMB deprotection of compound 9 furnished chitobiosyl azide 10 , which served as an acceptor for glycosylation with β‐thio‐tolyl donor 11 .…”

Section: Resultsmentioning

confidence: 99%

Synthesis of Azido‐Glycans for Chemical Glycomodification of Proteins

et al. 2018

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Chemically produced, accurately linkable oligosaccharides are of importance for the synthesis of neo‐glycoproteins. On the route to high‐mannose type N‐glycans, we present a convenient synthesis of several glycans bearing an azide moiety at the reducing end. An azido‐glycan core structure as valuable precursor was modified into the protected N‐glycan pentasaccharide core structure and the possibility of modular attachment of different antenna was demonstrated through synthesis of a pentamannose donor and glycosylation with the core structure. The azido function allows for chemical ligation with recombinantly modified proteins featuring noncanonical cyclooctyne amino acids, providing access to customized glycopatterns of glycoproteins, e.g., of antibodies that are of high interest for biopharmaceutical applications.

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“…366 Highly stable 2-phthalimidoglycosyl fluorides also found application in aminosugar synthesis. 367 For example, 2-phthalimidoglucopyranosyl fluoride 137b, obtained from 136 by a protecting group sequence followed by treatment with dimethylaminosulfur trifluoride (DAST) in THF, was reacted with glycosyl acceptor 142. 368 Amongst the activating conditions developed, Cp 2 HfCl 2 -AgClO 4 (Suzuki's et al protocol) 369 was chosen, providing disaccharide 143 in 81% yield.…”

Section: Disubstituted 2-amino-2-deoxyglycosyl Donorsmentioning

confidence: 99%