Themed collection Glycosylation: New methodologies and applications

M. Carmen Galan, Sabine Flitsch and Antony Fairbanks introduce the Organic & Biomolecular Chemistry themed collection on glycosylation: new methodologies and applications.

An overview of transition metal catalyzed glycosylation reactions is presented and the main trends in reactivity are discussed.

This contribution reviews the enzymatic synthesis, including optimisation efforts, of fluorinated carbohydrates involving fluorinated donors and/or acceptors, as well as the enzymatic activation of the fluorinated donors.

This review describes various methodologies for the stereoselective 1,2-cis glycosylation of L-rhamnose leading to β-L-rhamnosides and their applications in oligosaccharide synthesis.

Human xylosyl transferase can effectively install a xylose stereospecifically onto a peptide backbone on mg scales paving the way for efficient chemoenzymatic synthesis of proteoglycan glycopeptides and glycoproteins.

The first protection/deprotection-free process for radical C-glycosylation has been achieved through one-step preparable glycosyl dithiocarbamates (GDTCs).

Synthesis of sensitive coumarin α-GalNAc glycosides as substrates for droplet-based screening of GalNAcases.

Ethyl thioglycosides could be selectively activated in the presence of phenyl thioglycosides carrying the same or even more armed protecting group pattern.

This is the first example of a thioglycoligase that is able to catalyse the formation of S-glucuronides using aromatic thiols and a natural glucuronide donor.

Disaccharide glycosyl donors were synthesised and directly compared in glycosylations to assess their potential for heparan sulfate oligosaccharide synthesis.

The total synthesis of tricolorin A was achieved with high efficiency based on interrupted Pummerer reaction-mediated (IPRm) glycosylation and one-pot relay glycosylation.

The use of a continuous flow platform for the rapid and highly efficient construction of differentially protected glycals from commercial sources is described.

The practical synthesis of pseudo-enantiomeric carbohydrate-based NHC–Rh complexes bearing C1 or C3 sterically differentiated positions is reported. We show that steric bulk at either C1 or C3 leads to enantiotopic discrimination in the hydrosilylation of acetophenone.

An effective C-glycosylation protocol using N-(glycosyloxy)acetamides as donors promoted by SnBr₄ has been developed, delivering alkyl C-glycosides and aryl-β-C-glycosides in high yields.

The synthesis of bacillosamines carrying different functionalities at their C-2 and C-4 amine groups is described for the first time.

Electron-withdrawing groups and Lewis basic solvent enable 1,2-cis-selectivity.

Additive controlled glycosylation reactions are used for the construction of α-(1,2)-glucosidic linkages, such as those featuring in E. faecalis lipoteichoic acid.

Automated Glycan Assembly grants access to ionic oligosaccharides for structural studies.

Photo-induced glycosylations of several acceptors with trichloroacetimidate donors using bis(2-naphthyl)disulfide as an organo-Lewis photoacid (LPA) catalyst proceeded effectively to give the corresponding glycosides in good to high yields.

New hybrid glycopolymers were synthesized that contain two epitopes blocking GM1- and fucose-based intoxication modes of the cholera toxin.

A MUC1 glycopeptide bearing an unnatural β-glycosyl bond between the glycan and the peptide backbone was synthesized. The mimic can induce high levels of IgG antibodies cross-recognizing cancer cells expressing the native MUC1 glycoprotein.

Activation of reducing sugars in aqueous solution using DMC and triethylamine in the presence of phenols allows direct stereoselective conversion to the corresponding 1,2-trans aryl glycosides without the need for any protecting groups.

The monosaccharide Tn and the disaccharide STn are tumor antigens with similar structures and common biosynthetic pathways.

A practical route for the synthesis of hyaluronic acid oligosaccharides was developed, and a tetrasaccharide (GlcNAc–GlcA)₂ was identified as the minimum length that binds to human CD44 (K_D = 3.5 μM) using isothermal titration calorimetry.

A solvent-free, under air approach for the highly stereoselective synthesis of α-glycosides from glycosyl chloride donors, promoted by a triethylphosphite, tetrabutylammonium bromide, and N,N-diisopropylethylamine combination.

A collection of various sulfoforms of di- and trisaccharides of the linkage region of proteoglycans were prepared using a regioselective glycosylation. Preliminary results of the impact of sulfation on CSGalNAcT-1 is also reported.

The synthesis and use of a uniformly ¹³C labelled fucosyl donor as a general building block is demonstrated.

Chemoenzymatic synthesis of azido-functionalised asymmetric trehalose analogues that are resistant to enzymatic degradation to probe carbohydrate processing pathways in mycobacteria.

Polymethylhydrosiloxane (PMHS): a sub-stoichiometric reducing agent for reductive etherification of carbohydrate substrates and its application for one-pot protecting group manipulation

A new α1,4 galactosyltransferase has been characterised and used for the synthesis of natural and non-natural cell surface trisaccharide antigens.

This study has established a new strategy and new molecular tools for selective metabolic labeling of inositol on cancer cells, which should be useful for cancer targeting and study of GPI-anchored proteins.

GM3 gangliosides have been synthesized via late-stage α-sialylation using a macro-bicyclic sialyl donor. ¹⁹F solid-state NMR analysis of the C5-NHTFAc GM3 analog on a model membrane revealed the influence of cholesterol on glycan dynamics.

The synthesis of the invariant natural killer (iNK) T cell agonist β-mannosylceramide along with a series of fatty amide analogues is reported.

An S-linked disaccharide for the efficient synthesis of arabinoxylans.

An effective Pd(II)-catalyzed stereoselective C-glycosylation method has been successfully manifested for the synthesis of diversely functionalized 2,3-dideoxy C-aryl glycosides starting from glycals with a wide range of diaryliodonium salts.

Reported is the first stereoselective method for β-xylulofuranosylation, which employs 3,4-O-xylylene-protected thioglycoside donors.

β-Selective acetimidate formation followed by α-selective catalytic activation.

The first chemical synthesis of lacto-N-neohexaose (LNnH) has been completed using a convergent synthetic strategy.

The stereoselective introduction of the glycosidic bond is one of the main challenges in chemical oligosaccharide synthesis.

A bacterial CMP-5,7-di-N-acetyllegionaminic acid synthetase was characterized and used in one-pot multienzyme systems for efficient synthesis of Leg5,7Ac₂-glycosides and analogs.

Mixed sequence, C6-hydroxamate-modified alginate disaccharides are prepared using NIS/TMSOTf glycosylation.

Tetrasaccharides mimicking Burkholderia pseudomallei and Burkholderia mallei lipopolysaccharide O-antigens were synthesized and found to be highly reactive with Thai melioidosis patient serum, highlighting their potential as vaccine candidates.