Carbohydrate chemistry articles from across Nature Portfolio

A highly chemoselective method for the insertion of carbohydrates into existing oligosaccharides has been developed. The reaction sequence involves a selective Lewis-acid catalysed cleavage of one glycosidic bond followed by sequential construction of two new glycosidic bonds.

d-cyclodextrins are naturally occurring macrocyclic oligosaccharides that act as hosts for hydrophobic guests and are produced on a multi-tonne scale. Now, using chemical synthesis, mirror-image cyclodextrins are produced from l- instead of d-glucose units.

Molecular editing has been used for the late-stage functionalization of chemical scaffolds at the atomic level, however, chemically editing carbohydrates by inserting a foreign glycan remains underexplored. Here, the authors develop a cut-insert-stitch editing reaction sequence to insert various carbohydrates and activated hydroxyacids into oligosaccharides.

C-oligosaccharides are found in natural products and drug molecules, but their synthesis is challenging. Here, the authors report a strategy for the stereoselective and efficient synthesis of Coligosaccharides via palladium-catalyzed nondirected C1–H glycosylation/C2-alkenylation, cyanation, and alkynylation of 2-iodoglycals with glycosyl chloride donors.

The making of mirror-image versions of naturally occurring cyclodextrins (CDs) is challenging and constitutes an untouched goal of the CD community. Now a concise approach is developed for the diastereoselective synthesis of three mirror-image CDs in an efficient and scalable manner.

Characterizing highly-reactive glycosyl cation intermediates and understanding their glycosylation mechanisms are essential to the stereoselective synthesis of complex carbohydrates. Here the authors report a workflow that is utilized to characterize rhamnosyl 1,3-bridged dioxanium ions derived from C-3 p-anisoyl esterified donors.

Radical-mediated synthesis of N-glycosides is underdeveloped. Here a glycosyl radical-mediated N-glycosylation reaction using combined copper and photoredox catalysis is reported. This protocol exhibits high chemoselectivity and water tolerance, overcoming challenges associated with cationic glycosylation reactions.

Peptides and nucleic acids inspired the creation of synthetic analogues that fold and assemble on demand. By contrast, programmable glycan architectures remain mostly unexplored. In this Perspective, the authors propose that advances in synthesis and analysis could fuel the use of well-defined glycans in materials science and supramolecular chemistry.

A highly chemoselective method for the insertion of carbohydrates into existing oligosaccharides has been developed. The reaction sequence involves a selective Lewis-acid catalysed cleavage of one glycosidic bond followed by sequential construction of two new glycosidic bonds.

d-cyclodextrins are naturally occurring macrocyclic oligosaccharides that act as hosts for hydrophobic guests and are produced on a multi-tonne scale. Now, using chemical synthesis, mirror-image cyclodextrins are produced from l- instead of d-glucose units.

A preactivation-based one-pot glycosylation strategy was used to synthesize RN1 — a polysaccharide comprising 140 monosaccharide units isolated from Panax notoginseng, as well as a glycan fragment library. Evaluation of the biological activity of the glycans in vitro revealed that a decasaccharide fragment shows anti-pancreatic cancer activity.

A chemoenzymatic strategy is introduced whereby a glycan backbone is assembled enzymatically to give a core oligosaccharide that is subjected to chemical manipulations to install terminal epitopes. A library of oligosaccharides containing the human natural killer-1 epitope was synthesized, enabling evaluation of the binding specificities of serum antibodies of patients with anti-myelin-associated glycoprotein neuropathy.

Making ribonucleosides from ribose and nucleobases was the first prebiotic route to be suggested, but it is challenging to achieve with high selectivity and efficiency. Now, wet–dry cycles over acidified titanium minerals in water restore a traditional approach as the most atom-economical and sustainable method.

Advanced ¹⁷O NMR methods can help distinguish oxygen atoms from different hydrogen-bonding environments in glucose.