Glycosyl fluorides in glycosidations.
TL;DR: Several types of C-glycosyl compounds, such as aryl, allyl and alkyl C- Glycosyl derivatives, were also obtained by the glycosylation using gly cosyl fluorides and the corresponding nucleophile with or without a Lewis acid.
About: This article is published in Carbohydrate Research.The article was published on 2000-07-10. It has received 138 citations till now. The article focuses on the topics: Koenigs–Knorr reaction & Chemical glycosylation.
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TL;DR: Mechanistically, C-glycosylation reactions can involve glycosyl electrophilic/cationic species, anionic species, radical species, or transition-metal complexes, which are discussed as subcategories under each type of sugar precursor.
Abstract: Advances in the chemical synthesis of C-pyranosides/furanosides are summarized, covering the literature from 2000 to 2016. The majority of the methods take advantage of the construction of the glycosidic C—C bond. These C-glycosylation methods are categorized herein in terms of the glycosyl donor precursors, which are commonly used in O-glycoside synthesis and are easily accessible to nonspecialists. They include glycosyl halides, glycals, sugar acetates, sugar lactols, sugar lactones, 1,2-anhydro sugars, thioglycosides/sulfoxides/sulfones, selenoglycosides/telluroglycosides, methyl glycosides, and glycosyl imidates/phosphates. Mechanistically, C-glycosylation reactions can involve glycosyl electrophilic/cationic species, anionic species, radical species, or transition-metal complexes, which are discussed as subcategories under each type of sugar precursor. Moreover, intramolecular rearrangements, such as the Claisen rearrangement, Ramberg–Backlund rearrangement, and 1,2-Wittig rearrangement, which usuall...
314 citations
TL;DR: In this article, a method for metabolic oligosaccharide engineering that incorporates derivatized alkyne-bearing sugar analogs as "tags" into cellular glycoconjugates is presented.
Abstract: The present disclosure relates to a method for metabolic oligosaccharide engineering that incorporates derivatized alkyne-bearing sugar analogs as “tags” into cellular glycoconjugates. The disclosed method incorporates alkynyl derivatized Fuc and alkynyl derivatized ManNAc sugars into a cellular glycoconjugate. A chemical probe comprising an azide group and a visual probe or a fluorogenic probe is used to label the alkyne-derivatized sugar-tagged glycoconjugate. In one aspect, the chemical probe binds covalently to the alkynyl group by Cu(I)-catalyzed [3+2] azide-alkyne cycloaddition and is visualized at the cell surface, intracellularly, or in a cellular extract. The labeled glycoconjugate is capable of detection by flow cytometry, SDS-PAGE, Western blot, ELISA or confocal microscopy, and mass spectrometry.
294 citations
TL;DR: Recent advances in the development of fully synthetic sub-unit carbohydrate-based cancer vaccines will be discussed.
201 citations
TL;DR: This review describes the methodologies for one- Pot protection and their one-pot glycosylation into the complex glycans and the chronological developments associated with automated syntheses of oligosaccharides.
Abstract: Carbohydrates, which are ubiquitously distributed throughout the three domains of life, play significant roles in a variety of vital biological processes. Access to unique and homogeneous carbohydrate materials is important to understand their physical properties, biological functions, and disease-related features. It is difficult to isolate carbohydrates in acceptable purity and amounts from natural sources. Therefore, complex saccharides with well-defined structures are often most conviently accessed through chemical syntheses. Two major hurdles, regioselective protection and stereoselective glycosylation, are faced by carbohydrate chemists in synthesizing these highly complicated molecules. Over the past few years, there has been a radical change in tackling these problems and speeding up the synthesis of oligosaccharides. This is largely due to the development of one–pot protection, one–pot glycosylation, and one–pot protection–glycosylation protocols and streamlined approaches to orthogonally protect...
175 citations
TL;DR: The basic concepts that have guided the exploration of new chemical reactions by giving examples of results from my research group are described, and it can be said that by reviewing what the authors had done before, they were able to expand on it to achieve new outcomes.
Abstract: This Review describes the basic concepts that have guided our exploration of new chemical reactions by giving examples of results from my research group. Our strategy of carrying out research is to investigate three to four different topics at a time so we can gather as many results as possible. These may at first appear unrelated to each other but may have the potential to be united into a greater hypothesis after repeated feedback. Three scenarios from our research are presented: the "oxidative-reductive condensation reaction" devised in 1960, which after an interval of nearly 40 years brought forth the new concept of using compounds of structure Ph(2)POR as reducing reagents; the "TiCl(4)-aldol reaction" of 1973 that eventually led to the present "base-promoted aldol reaction" through a chain of ideas; and the "glycosylation reaction using fluorosugars" from 1984 which recently bloomed into "stereocontrolled glycosylation". Thus, it can be said that by reviewing what we had done before, we were able to expand on it to achieve new outcomes.
168 citations
References
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TL;DR: Emphasis is placed on glycoside and saccharide formation by 1-O-alkylation, on the trichloroacetimidate method, and on activation through the formation of glycosylsulfonium salts and Glycosyl fluorides.
Abstract: Glycoproteins, glycolipids, and glycophospholipids (glycoconjugates) are components of membranes. The oligosaccharide residue is responsible for intercellular recognition and interaction; it acts as a receptor for proteins, hormones, and viruses and governs immune reactions. These significant activities have stimulated interest in oligosaccharides and glycoconjugates. With their help it should be possible to clarify the molecular basis of these phenomena and to derive new principles of physiological activity. Major advances in the synthesis of oligosaccharides have been made by the use of the Koenigs-Knorr method, in which glycosyl halides in the presence of heavy-metal salts are employed to transfer the glycosyl group to nucleophiles. The disadvantages of this procedure have led to an intensive search for new methods. Such methods will be discussed in this article. Emphasis is placed on glycoside and saccharide formation by 1-O-alkylation, on the trichloroacetimidate method, and on activation through the formation of glycosylsulfonium salts and glycosyl fluorides.
1,185 citations
TL;DR: In this paper, glucosides and disaccharides are prepared in good yields from 2,3,4,6-tetra-O-benzyl-β-D-glucopyranosyl fluoride and hydroxy compounds in the presence of stannous chloride and silver perchlorate.
Abstract: Glucosides and disaccharides are prepared in good yields from 2,3,4,6-tetra-O-benzyl-β-D-glucopyranosyl fluoride and hydroxy compounds in the presence of stannous chloride and silver perchlorate. In most cases, α-glucosides are predominantly (α⁄β=80⁄20∼92⁄8) obtained.
280 citations
TL;DR: The title glycosylation method is economical and operationally simple as mentioned in this paper, and the steric course is highly influenced by the nature of the reaction media, which is the most common reaction media used in glycolysis.
263 citations
TL;DR: The combination of Cp 2 MCl 2 -AgClO 4, (M=Zr, Hf) is effective for the activation of glycosyl fluorides, which enables the highly β-selective glycoside formation of D-mycinose by performing the reaction in benzene.
194 citations
TL;DR: In this paper, Cp 2 HfCl 2 -AgClO 4 is particularly effective for this conversion, which leads to initial O-glycoside formation followed by rearrangement to C-congener.
151 citations