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Koenigs–Knorr reaction

About: Koenigs–Knorr reaction is a(n) research topic. Over the lifetime, 106 publication(s) have been published within this topic receiving 4521 citation(s).
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Journal ArticleDOI
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.

1,158 citations



Book ChapterDOI
TL;DR: This chapter analyzes the importance of thioclycosides as the glycosyl donors in oligosaccharide synthesis and the transfer of the Armed–Disarmed concept to thioglycoside Glycosylation reactions is elaborated.
Abstract: Publisher Summary This chapter analyzes the importance of thioclycosides as the glycosyl donors in oligosaccharide synthesis. The presence and biological importance of oligosaccharide structures, usually as the components of glycolipids and glycoproteins, in bacterial capsular and cell-wall polysaccharides, in mammalian cell membranes, in cytoplasm, and in extra-cellular fluids are well documented. Acylated glycosyl thiocyanates are made by the treatment of acylated glycopyranosyl halides with potassium thiocyanate. An attractive feature of thioglycosides as the glycosyl donors in oligosaccharide synthesis is that they are readily converted into all of the other glycosyl donors. The glycosyl bromide can also be converted into a 4-pentenyl glycoside, which becomes a glycosyl donor by promotion with an iodonium compound. Tris(4-bromophenyl)ammoniurnyl hexachloroantimonate (TBPA) differs from the other promoters in the context that its cation is a radical and produces radical cationic sulfonium ions such as glycosylating species from thioglycosides. In acetonitrile as solvent, and with a nonparticipating 2-substituent in the glycosyl donor, 1,2-trans glycosides are formed as a result of solvent participant. The transfer of the Armed–Disarmed concept to thioglycoside glycosylation reactions is also elaborated in the chapter.

305 citations


Book
01 Jan 2008
Abstract: GENERAL ASPECTS OF THE GLYCOSIDIC BOND FORMATION GLYCOSIDE SYNTHESIS FROM ANOMERIC HALIDES Glycosyl Fluorides Glycosyl Chlorides, Bromides, and Iodides GLYCOSIDE SYNTHESIS FROM 1-OXYGEN-SUBSTITUTED GLYCOSYL DONORS Hemiacetals and O-Acyl/Carbonyl Derivatives Glycosyl Imidates Anomeric Transglycosylation Phosphites, Phosphates, and Other O--P Derivatives GLYCOSIDE SYNTHESIS FROM 1-SULFUR/SELENIUM-SUBSTITUTED DERIVATIVES Thioalkyl and Thioaryl Glycosides Sulfoxides, Sulfimides, and Sulfones Xanthates, Thioimidates, and Other Thio Derivatives Selenoglycosides OTHER METHODS FOR GLYCOSIDE SYNTHESIS Orthoesters and Related Derivatives Dehydro and Anhydro Derivatives Miscellaneous Glycosyl Donors Indirect and Special Methods

144 citations


Journal ArticleDOI
Kazunobu Toshima1
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.
Abstract: This short review deals with the recent progress in chemical O-glycosidation and C-glycosylation methods using glycosyl fluorides as glycosyl donors. Pyranosyl and furanosyl fluorides were effectively activated by fluorophilic reagents such as SnCl2-AgClO4, SnCl2-TrClO4, SnCl2-AgOTf, TMSOTf, SiF4, BF3 x Et2O, TiF4, SnF4, Cp2MCl2-AgClO4 (M = Zr or Hf), Cp2ZrCl2-AgBF4, Cp2HfCl2-AgOTf, Bu2Sn(ClO4)2, Me2GaCl, Tf2O, LiClO4, Yb(OTf)3, La(ClO4)3 x nH2O, La(ClO4)3 x nH2O-Sn(OTf)2, Yb-Amberlyst 15, SO4/ZrO2, Nafion-H, montmorillonite K-10, and TrB(C6F5)4 to react with alcohols to give the corresponding O-glycosides in high yields. Furthermore, several types of C-glycosyl compounds, such as aryl, allyl and alkyl C-glycosyl derivatives, were also obtained by the glycosylation using glycosyl fluorides and the corresponding nucleophile with or without a Lewis acid.

131 citations


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Performance
Metrics
No. of papers in the topic in previous years
YearPapers
20191
20172
20161
20151
20141
20136