Ring-Opening of Aziridine-2-Carboxamides with Carbohydrate C1-O-Nucleophiles. Stereoselective Preparation of α- and β-O-Glycosyl Serine Conjugates
Daniel A. Ryan,David Y. Gin +1 more
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TLDR
The stereoselective formation of the alpha-GalNAc-Ser linkage via the ring opening of aziridine-2-carboxamides with pyranose C1-O-nucleophiles is described, which led to the development of the o-allylbenzyl (ABn) moiety as a new C-terminus carboxyl protective group.Abstract:
The stereoselective formation of the α-GalNAc-Ser linkage via the ring opening of aziridine-2-carboxamides with pyranose C1-O-nucleophiles is described. The process is tolerant to the native C2-NHAc group, can be modulated to provide either the α- or β-glycoside through judicious choice of solvent and metal counterion, and is amenable to other classes of O-glycosyl-Ser constructs such as the β-GlcNAc-Ser and α-Man-Ser linkages. This coupling reaction also led to the development of the o-allylbenzyl (ABn) moiety as a new C-terminus carboxyl protective group, which allows for the use of novel methods for N- and C-terminus extension of amino acids following carbohydrate conjugation.read more
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Recent Advances in Transition Metal-Catalyzed Glycosylation
Matthew J. McKay,Hien M. Nguyen +1 more
TL;DR: Recent advancement is highlighted by examining strategies that employ transition metal catalysis in the synthesis of oligosaccharides and glycoconjugates, which are mild and effective for constructing glycosidic bonds with reduced levels of waste through utilization of sub-stoichiometric amounts of transition metals.
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Nickel-catalyzed stereoselective glycosylation with C(2)-N-substituted benzylidene D-glucosamine and galactosamine trichloroacetimidates for the formation of 1,2-cis-2-amino glycosides. Applications to the synthesis of heparin disaccharides, GPI anchor pseudodisaccharides, and α-GalNAc.
TL;DR: A novel method for the synthesis of 1,2-cis-2-amino glycosides via nickel-catalyzed α-selective glycosylation with C(2)-N-substituted benzylidene D-glucosamine and galactosamine trichloroacetimidates is developed.
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Venturing beyond Donor-Controlled Glycosylation: New Perspectives toward Anomeric Selectivity
TL;DR: This Account presents mainly the advancements beyond the conventional donor-controlled strategies over the past decade, with emphasis placed on mechanistic explanations of anomeric selectivities, thereby providing perspectives to inspire further progress toward a generalized unified strategy for preparing every type of glycan.
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Physico-chemical properties improvement of soy protein isolate films through caffeic acid incorporation and tri-functional aziridine hybridization
TL;DR: In this article, tri-functional trimethylolpropane-tris-(2-methyl-1-aziridine) propionate and plant-derived caffeic acid (CA) were used as a cross-linking system to simultaneously enhance the strength and retain elongation at break (EB) of soy protein isolate (SPI) films.
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Direct synthesis of 2-deoxy-β-glycosides via anomeric O-alkylation with secondary electrophiles.
TL;DR: It was found a free hydroxyl group at C3 of the 2-deoxy-sugar-derived lactols is required in order to achieve synthetically efficient yields.
References
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Mucins in cancer: Protection and control of the cell surface
TL;DR: Mucins — large extracellular proteins that are heavily glycosylated with complex oligosaccharides — establish a selective molecular barrier at the epithelial surface and engage in morphogenetic signal transduction.
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New Methods for the Synthesis of Glycosides and Oligosaccharides—Are There Alternatives to the Koenigs‐Knorr Method? [New Synthetic Methods (56)]
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.
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The azidonitration of tri-O-acetyl-D-galactal
R. U. Lemieux,R. M. Ratcliffe +1 more
TL;DR: In this article, a reaction of 3,4,6,tri-O-acetyl-D-galactal with excess ammonium nitrate and sodium azide in acetonitrile produced 2-azido-1-nitrate addition products (53% β-Galacto, 22% α-GalACTo, and 8% α -Ta...
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Ns strategies: a highly versatile synthetic method for amines
Toshiyuki Kan,Tohru Fukuyama +1 more
TL;DR: The total synthesis of linear and/or macrocyclic natural polyamines can be accomplished efficiently using nitrobenzenesulfonamides as both a protecting and activating group.