201053-37-4Relevant academic research and scientific papers
Practical synthesis of spirocyclic bis-C,C-glycosides. Mechanistic models in explanation of rearrangement stereoselectivity and the bifurcation of reaction pathways
Paquette, Leo A.,Kinney, Margaret J.,Dullweber, Uta
, p. 1713 - 1722 (1997)
The susceptibility of glycal-derived carbinols to acid-catalyzed ring expansion is described. In the systems prepared from cyclopentanone, Ferrier ionization precedes the pinacol-like Wagner-Meerwein shift, thermodynamic control operates, and high stereoselectivity is seen if a C(6) substituent is present. In contrast, the adducts to cyclobutanone exhibit release of ring strain under kinetically controlled conditions and intercept the oxonium species reversibly formed via direct proton transfer. The results show that the substituents positioned on the glycal ring have a pronounced influence on whether a chair-like or twist-boat transition state geometry is adopted primarily. The composite reaction profiles reveal for the first time the fundamental importance of exothermicity and of substitution in these spiro glycosidation reactions. Since optical activity is preserved in all instances, the utility of this chemistry for the synthesis of bis-C,C-glycosides and more complex oxacyclics appears promising.
?-Glycosyl Trifluoroborates as Precursors for Direct ?±-C-Glycosylation: Synthesis of 2-Deoxy-?±-C-glycosides
Takeda, Daiki,Yoritate, Makoto,Yasutomi, Hiroki,Chiba, Suzuka,Moriyama, Takahiro,Yokoo, Atsushi,Usui, Kazuteru,Hirai, Go
, p. 1940 - 1944 (2021)
C-Glycosides are metabolically stable mimics of natural O-glycosides and are expected to be useful tools for investigation of the biological functions of glycans. Here, we describe the synthesis of a series of aryl and vinyl C-glycosides by stereoinvertive sp3-sp2 cross-coupling reactions of 2-deoxyglycosyl boronic acid derivatives with aryl or vinyl halide, mediated by a photoredox/nickel dual catalytic system. Hydrogenation of the vinyl C-glycosides afforded C-linked 2′-deoxydisaccharide analogues.
Aziridine Ring Opening as Regio-and Stereoselective Access to C-Glycosyl-Aminoethyl Sulfide Derivatives
Le?niak, Stanis?aw,Malinowska, Martyna,Tracz, Aleksandra,Zawisza, Anna
, (2022/03/23)
A short synthetic route to stereoselective access to C-glycosyl-aminoethyl sulfide derivatives has been developed through the reaction of tributhyltin derivatives of glycals with aziridinecarboaldehyde and the regioselective ring opening of a chiral aziridine with thiophenol. The absolute configurations of the resulting diastereoisomers were determined by 1H NMR spectroscopy.
General Approach to Five-Membered Nitrogen Heteroaryl C-Glycosides Using a Palladium/Copper Cocatalyzed C-H Functionalization Strategy
Zhang, Shuo,Niu, You-Hong,Ye, Xin-Shan
supporting information, p. 3608 - 3611 (2017/07/15)
A general approach to the synthesis of diverse heteroaryl-C-Δ1,2-glycosides has been developed by employing the Pd(OAc)2/CuI cocatalyzed direct cross-coupling of five-membered nitrogen heterocycles with 1-iodoglycals in a C-H activation manner. Using this method, 27 examples of heteroaryl-C-Δ1,2-glycosides, containing indoles, thiazoles, benzothiazoles, imidazoles, benzimidazoles, and benzoxazoles as aglycones were obtained in 43-99% yield.
C(1→4)-linked disaccharides through carbonylative Stille cross-coupling
Steunenberg, Peter,Jeanneret, Vincent,Zhu, Yao-Hua,Vogel, Pierre
, p. 337 - 346 (2007/10/03)
A tinglucal tributyl[4,6-O-bis(t-butyl)silylidene-3-O-tris(isopropyl)silyl] tin 7 and a triflate derived from isolevoglucosenone (1R,4R,5R)-4-benzyloxy-6,8- dioxabicyclo[3.2.1]oct-2-en-2-yl trifluoromethanesulfonate 10 undergo the carbonylative Stille con
Mercuration-reductive demercuration of glycals: A mild and convenient entry to 2-deoxy-sugars
Bettelli, Enzo,Cherubini, Paola,D'Andrea, Piero,Passacantilli, Pietro,Piancatelli, Giovanni
, p. 6011 - 6018 (2007/10/03)
Protected glycals, derived from mono-, di- and tri-saccharides, were easily and efficiently converted into the corresponding 2-deoxy-sugars, by reaction with mercuric(II) acetate/sodium borohydride in a polar solvent at 0 °C. The mild and non acidic react
Synthesis of Asialo GM1. New insights in the application of sulfonamidoglycosylation in oligosaccharide assembly: Subtle proximity effects in the stereochemical governance of glycosidation
Kwon, Ohyun,Danishefsky, Samuel J.
, p. 1588 - 1599 (2007/10/03)
The total synthesis of asialo GM1 (1a) has been accomplished. Using related chemistry, the methyl glycoside of the asialo compound (1b) has also been synthesized. These kinds of compounds have been identified as potential ligands for bacterial and viral infection sites. A simpler structure, which has also been identified for its infection attracting structure in the context of glycopeptides and glycolipids (methyl glycoside 2), has also been synthesized. The key common phase in the syntheses involves the sulfonamidoglycosidation reaction which is used to create a β-linkage leading to a ga1NAc residue joined to the C4 hydroxyl group of a galactose unit either as a monosaccharide (see compound 2) or as C4' in the context of a lactosyl moiety. During the course of these studies there was encountered an unusual 'proximal hydroxyl' directing effect. Thus, when C4 on the galactose ring of an azaglycosylating donor bears a free hydroxyl (see, for instance, compound 13), β-glycoside formation predominates. When this hydroxyl group is blocked, the process tends in the direction of α-glycoside formation (see compound 32). These findings were explained as arising from a critical intramolecular hydrogen bond between the C4 axial hydroxyl of the galactose donor and its proximal pyranosidal ring oxygen. This interaction stabilizes conformations from which β-glycosidation predominates.
