Comparison of glycosyl donors: a supramer approach

• Anna V. Orlova,
• Nelly N. Malysheva,
• Maria V. Panova,
• Nikita M. Podvalnyy,
• Michael G. Medvedev and
• Leonid O. Kononov

Beilstein J. Org. Chem. 2024, 20, 181–192, doi:10.3762/bjoc.20.18

• spectrum of phenomena including virus and bacterial recognition and cellular adhesion [1][2][3][4][5][6][7][8][9][10][11]. The development of effective means for the preparation of α-sialosides through chemical glycosylation (sialylation) received considerable attention since sialo-containing saccharides

SnCl₄-catalyzed solvent-free acetolysis of 2,7-anhydrosialic acid derivatives

• Kesatebrhan Haile Asressu and
• Cheng-Chung Wang

Beilstein J. Org. Chem. 2019, 15, 2990–2999, doi:10.3762/bjoc.15.295

• ][15][16]. Moreover, the similar chemical shifts of positions H-3eq and H-3ax in the 1H NMR spectra of α-sialosides 6, 21, and 25 became much more different for the ring-opening products 12, 22, and 26, again representative of the β-configuration. Next, SnCl4-catalyzed acetolysis was evaluated with 2,7

Anomeric modification of carbohydrates using the Mitsunobu reaction

• Julia Hain,
• Patrick Rollin,
• Werner Klaffke and
• Thisbe K. Lindhorst

Beilstein J. Org. Chem. 2018, 14, 1619–1636, doi:10.3762/bjoc.14.138

• arylglycosylation was also extended for the synthesis of aureolic acid antibiotics [21][51][52]. In search of convenient methods for the synthesis of aryl sialosides, Gao et al. explored the scope of the Mitsunobu reaction with the sialic acid derivative 49, employing a range of phenols 50–58 in acetonitrile to

• achieve sialosides 59–67, albeit with modest anomeric selectivity (Scheme 10) [25]. Interestingly, no correlation between the pKa of the employed acids and the stereoselectivity of the reaction could be established in this case, since similar anomeric mixtures were obtained throughout all experiments. In

• -configured glycosyloxyphosphonium ions, which are in turn displaced by the nucleophile in the expected SN2 fashion, resulting in a respective anomeric mixture of products (cf. Scheme 2). In contrast to this, the yields of the obtained aryl sialosides strongly correlated with the pKa of the utilized phenols

Carbohydrate inhibitors of cholera toxin

• Vajinder Kumar and
• W. Bruce Turnbull

Beilstein J. Org. Chem. 2018, 14, 484–498, doi:10.3762/bjoc.14.34

• galactosides have millimolar Kds and little interaction can be detected for simple sialosides [20]. The distance separating the binding sites is similar for all members of the AB5 toxin family and is believed to be instrumental in clustering the glycolipid ligands in such a way that membrane curvature is

Automated synthesis of sialylated oligosaccharides

• Davide Esposito,
• Mattan Hurevich,
• Bastien Castagner,
• Cheng-Chung Wang and
• Peter H. Seeberger

Beilstein J. Org. Chem. 2012, 8, 1601–1609, doi:10.3762/bjoc.8.183

• external partners such as cells and viruses. Straightforward access to sialosides is required in order to study their biological functions on a molecular level. Here, automated oligosaccharide synthesis was used to facilitate the preparation of this class of biomolecules. Our strategy relies on novel

• sialyl α-(2→3) and α-(2→6) galactosyl imidates, which, used in combination with the automated platform, provided rapid access to a small library of conjugation-ready sialosides of biological relevance. Keywords: automated synthesis; disaccharide building blocks; solid-phase synthesis; sialic acid

• ; sialosides; Introduction Sialic acid (Sia) belongs to a family of nonulosonic acids, i.e., monosaccharides equipped with a carboxylic moiety and a nine-carbon backbone, which play a unique role in glycobiology. Sia-containing glycans mediate pathogen invasion [1] and are involved in signalling cascades