Progress and challenges in the synthesis of sequence controlled polysaccharides

• Giulio Fittolani,
• Theodore Tyrikos-Ergas,
• Denisa Vargová,
• Manishkumar A. Chaube and
• Martina Delbianco

Beilstein J. Org. Chem. 2021, 17, 1981–2025, doi:10.3762/bjoc.17.129

• prepared to study interactions with bacterial microcrystalline cellulose [108]. The glycosyl fluoride donors were also polymerized to give (XXXG)n and (XLLG)n with MW up to 12000 [109]. The synthesis of the highly branched (XLFG)n polysaccharides required the additional fucosyltransferase AtFUT1 to

• studies revealed that long β(1–3)-glucan structures adopt a parallel, triple helical structures [146]. A glycosynthase derived from Bacillus licheniformis could polymerize glycosyl fluoride donors to prepare artificial mixed linkage β-glucans with an average molecular mass of 10–15 kDa [147]. The better

• respective glycosyl fluoride and used for enzymatic polymerization catalyzed by XynAE265G (Scheme 8B) [7]. This approach generated polymers 62a–g with well-defined substitution patterns. Differences in solubility were observed for certain patterns, affecting the efficiency of polymerization and the DPs of

Metal-free glycosylation with glycosyl fluorides in liquid SO₂

• Krista Gulbe,
• Jevgeņija Lugiņina,
• Edijs Jansons,
• Artis Kinens and
• Māris Turks

Beilstein J. Org. Chem. 2021, 17, 964–976, doi:10.3762/bjoc.17.78

• equilibrium. Keywords: fluorosulfite; glycosyl fluoride; Lewis acid; liquid sulfur dioxide; metal-free glycosylation; Introduction The glycosylation reaction is still one of the most important and basic synthetic strategies in carbohydrate chemistry that provides access to the various types of

• oligosaccharides and glycopeptides under basic aqueous conditions [32][33]. Nevertheless, most of the conventional conditions for glycosyl fluoride activation have considerable drawbacks in terms of atom efficiency and environmental impact. These methods generally require (1) stoichiometric amounts of promoters

• to the previous report [63], in our case the reaction was not fully stopped by changing the reaction vessel from glass to PTFE tube. At this point, we can confirm the ability of SO2 to activate the glycosyl fluoride with a probable co-promoting assistance of a glass vessel. Next, in order to increase

Synthetic and semi-synthetic approaches to unprotected N-glycan oxazolines

• Antony J. Fairbanks

Beilstein J. Org. Chem. 2018, 14, 416–429, doi:10.3762/bjoc.14.30

• was used by Wang for the more extended synthesis of a dodecasaccharide oxazoline (Scheme 6) [78]. In this case selective removal of the PMB protecting group at OH-3 was followed by glycosylation with a pentasaccharide glycosyl fluoride donor, comprising one galactose, one glucose, and three mannose

Intramolecular glycosylation

• Xiao G. Jia and
• Alexei V. Demchenko

Beilstein J. Org. Chem. 2017, 13, 2028–2048, doi:10.3762/bjoc.13.201

• was accomplished in 97% yield and the resulting conjugate was converted into glycosyl fluoride by the treatment with DAST and NBS in 89% yield. Finally, selective cleavage of p-methylbenzyl ethers was accomplished with H2 over Pd(OH)2/C to provide donor–accepter conjugate 18 in 93% yield. Subsequent

Strategies toward protecting group-free glycosylation through selective activation of the anomeric center

• A. Michael Downey and
• Michal Hocek

Beilstein J. Org. Chem. 2017, 13, 1239–1279, doi:10.3762/bjoc.13.123

• fashion [58][59]. Therefore, they postulated that by using the correct divalent cation and suitable Lewis acid/Lewis base pairing, the necessary transition-state organization to favor glycosylation of a glycosyl fluoride would outcompete hydrolysis in the aqueous medium. This would lead to a simple non

Galactan synthesis in a single step via oligomerization of monosaccharides

• Marius Dräger and
• Amit Basu

Beilstein J. Org. Chem. 2014, 10, 2658–2663, doi:10.3762/bjoc.10.279

• : arabinogalactan protein; glycosyl fluoride; glycosylation; oligosaccharides; Introduction Despite numerous recent advances in the synthesis of complex oligosaccharides, unlike polypeptide or oligonucleotide assembly, their preparation remains far from a routine endeavor. The critical step in oligosaccharide

Sordarin, an antifungal agent with a unique mode of action

• Huan Liang

Beilstein J. Org. Chem. 2008, 4, No. 31, doi:10.3762/bjoc.4.31

• reaction of sordaricin ester 34 with glycosyl fluoride 35. Unlike previous syntheses, the present one utilized an intramolecular Tsuji-Trost reaction [29] of allylic carbonate 37 to build the core of sordaricin 36. In turn, compound 37 was prepared from bicyclic ketone 38, which was derived from