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A straightforward synthesis of the pentasaccharide with a readily available linker arm corresponding to the O-antigenic polysaccharide of Acinetobacter junii strain 65 has been achieved in good yield. The synthesis has been carried out using thioglycosides as glycosyl donor in the presence of a combination of N-iodosuccinimide (NIS) and trifluoromethanesulfonic acid (TfOH) as thiophilic activator. The yields of the glycosylation steps were very good with satisfactory stereochemistry at the glycosidic linkages. The pentasaccharide derivative has also been obtained using a one-pot iterative glycosylation strategy., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

An efficient synthetic strategy has been developed to achieve a pyruvic acid acetal containing tetrasaccharide repeating unit corresponding to the K82 capsular polysaccharide of Acinetobacter baumannii LUH5534 strain in very good yield. The synthetic scheme involves the use of suitably functionalized monosaccharide thioglycosides as glycosyl donors and a combination of N-iodosuccinimide (NIS) and trimethylsilyl trifluoromethanesulfonate (TMSOTf) as thiophilic glycosylation activator to furnish satisfactory yield of the products with appropriate stereochemistry at the glycosidic linkages. Incorporation of the (R)-pyruvic acid acetal in the d-galactose moiety was achieved in very good yield by the treatment of the diol derivative with methyl 2,2-bis(p-methylphenylthio)propionate in the presence of a combination of NIS and triflic acid., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

Synthesis of the pentasaccharide repeating unit of the cell O-polysaccharide produced by Salmonella milwaukee O:43 strain (group U) has been achieved in very good yield adopting a convergent stereoselective [3 + 2] block glycosylation strategy. Thioglycosides and glycosyl trichloroacetimidate derivative were used as glycosyl donors in the presence of a combination of N-iodosuccinimide (NIS) and trimethylsilyl trifluoromethanesulfonate (TMSOTf) as thiophilic activator and TMSOTf as trichloroacetimidate activator respectively. The stereochemical outcome of all glycosylation reactions was excellent., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

A convenient reaction condition has been developed for the preparation of 1,6-anhydro-1-thio-β-d-glycopyranose derivatives in excellent yield. The reaction condition is significantly fast, clean and can be scaled up for its use in the organic synthesis., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier Ltd. All rights reserved.)

A concise synthetic strategy have been developed for the synthesis of the sialic acid-containing tetrasaccharide repeating unit of the cell wall O-antigen of Escherichia coli (E. coli) O131 strain using regio- and stereoselective (2 → 6)-α-glycosylations of judiciously protected sialic acid thioglycoside derivatives. Perchloric acid supported over silica (HClO 4 -SiO 2 ) in combination with N-iodosuccinimide (NIS) has been used in the stereoselective activation of thioglycoside derivatives as well as used as a solid acid for the functional group modifications. Appropriate stereoselectivity was achieved in the glycosylation steps involved in the synthetic strategy., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2022 Elsevier Ltd. All rights reserved.)

Reduction of diselenides using a combination of hydrazine monohydrate and potassium hydroxide (KOH) followed by the treatment of the selenolate ions generated in situ with glycosyl halides under a one-pot, two-step phase transfer reaction condition resulted in the formation of beta-selenoglycosides in excellent yield. In addition, selenium linked disaccharide derivatives with beta-glycosidic linkages were also prepared by the reductive cleavage of diglycosyl diselenide derivatives in very good yield. The reaction condition is non-hazardous and high yielding for scaling up., (Copyright © 2022 Elsevier Ltd. All rights reserved.)

An efficient synthetic strategy has been developed for the synthesis of the sialic acid containing pentasaccharide repeating unit of the cell wall O-antigen of Streptococcus group B type VI strain involving stereoselective α-glycosylation of sialic acid thioglycoside derivative. Stereoselective glycosylation of glycosyl trichloroacetimidate derivatives and thioglycosides were carried out using perchloric acid supported over silica (HClO 4 -SiO 2 ) as a solid acid catalyst. A panel of sialic acid donors has been screened for achieving satisfactory yield and stereochemical outcome of the glycosylation reaction., (Copyright © 2021 Elsevier Ltd. All rights reserved.)

Selective acetolysis of the primary benzyloxy groups in a wide variety of carbohydrate derivatives was achieved in excellent yield using acetic anhydride and perchloric acid supported over silica (HClO 4 -SiO 2 ) as a solid acid catalyst in a fast reaction condition without using any organic solvent. The reaction condition is significantly rapid and can be scaled up for its use in the multi-step oligosaccharide synthesis., (Copyright © 2019 Elsevier Ltd. All rights reserved.)

A convergent synthesis of the hexasaccharide as its 2-aminoethyl glycoside corresponding to the repeating unit of the cell wall polysaccharide of Bifidobacterium animalis subsp. lactis LKM512 has been achieved applying a [4 + 2] glycosylation strategy. The disaccharide thioglycoside donor was prepared by combining a d-galactofuranosyl thioglycoside with another l-rhamnosyl thioglycoside acceptor. The yields of the individual glycosylation steps were highly satisfactory with excellent stereo outcome. An α-glycosidic linkage of the d-galactofuranosyl moiety in the hexasaccharide was achieved in very good yield., (Copyright © 2018 Elsevier Ltd. All rights reserved.)

Novel one-pot reaction conditions have been developed for the preparation of glycosyl thiourea derivatives directly from glycosyl azides mediated by a combination of sulfamic acid and sodium iodide. The reaction conditions were clean, non-toxic and the products were isolated in good to excellent yield., (Copyright © 2016 Elsevier Ltd. All rights reserved.)

The tetrasaccharide repeating unit of the O-antigen of Escherichia coli O174 strain was synthesized applying sequential glycosylations of suitably functionalized monosaccharide intermediates. Activation of glycosyl trichloroacetimidate derivatives using nitrosyl tetrafluoroborate (NOBF4) has been used during the synthesis. The glycosylation steps were high yielding with satisfactory stereo outcome.

Synthesis of the pentasaccharide repeating unit of the O-antigen of Escherichia coli O13 strain has been achieved using a straightforward linear synthetic strategy. Similar reaction conditions have been used for all glycosylations as well as protective group manipulations. All intermediate steps are high yielding and the glycosylation steps are stereoselective. The synthesized pentasaccharide was subjected to conformational analysis using 2D ROESY NMR spectral analysis and molecular dynamics (MD) simulation to get detailed information on conformation of the molecule in aqueous solution., (Copyright © 2014 Elsevier Ltd. All rights reserved.)

A straightforward synthesis of the pentasaccharide with all α-linked glycosyl linkages corresponding to the cell wall O-antigen of Escherichia coli 19ab has been achieved in excellent yield using sequential glycosylations of monosaccharide intermediates. The structure of the target compound and its synthetic intermediates were unambiguously characterized using their spectral analysis. A generalized glycosylation condition has been used in all glycosylations and minimum number of protecting group manipulations were involved during the synthesis of the target compound., (Copyright © 2012 Elsevier Ltd. All rights reserved.)

Reaction of glycal derivatives with alcohols or glycosyl acceptors in the presence of N-bromosuccinimide (NBS) and diphenyldiselenide resulted in the formation of alkyl 2-deoxy-2-phenylselenyl glycosides or disaccharide derivatives in excellent yield. The reactions are reasonably fast and considerable stereo-selectivity was observed in the preparation of disaccharide derivatives., (Copyright © 2012 Elsevier Ltd. All rights reserved.)

Convergent synthesis of a tetrasaccharide analog corresponding to the repeating unit of the O-polysaccharide of Salmonella enterica O59 is presented. A thioglycoside disaccharide donor was prepared by the glycosylation of two thioglycosides by tuning their relative reactivity. An unexpected stereochemical outcome was observed in a glycosylation using an ethyl 2-O-acetyl-3-O-benzyl-4,6-O-bensylidene-thio-galactoside donor, where the alpha-galactoside was formed in spite of the presence of the 2-O-acetyl participating group., (Copyright © 2012 Elsevier Ltd. All rights reserved.)

Di- and trisaccharide fragments related to the repeating unit of the O-antigen of Escherichia coli O83:K24:H31 have been synthesized as their methyl glycoside analogs starting from readily available monosaccharides.

Selective and per-O-acylation of carbohydrate derivatives using acyl chlorides and Al2O3, a solid support reagent, is reported. This protocol does not require the addition of any base or activator. This methodology has been further extended to the selective acylation of carbohydrate diols and the one-pot preparation of acetylated glycosyl chlorides direct from free reducing sugars. The yields obtained in most of the cases are excellent.

A rapid oxidation of thioglycosides to glycosyl sulfones has been achieved using a combination of KMnO4 and CuSO4*5H2O in acetonitrile and water. This reaction protocol has many advantages compared to other methods available for this transformation, including compatibility with acid and base labile functional groups used for the protection of carbohydrates, high yields, fast reaction times, and moderate reaction temperatures. The yields obtained were excellent in all cases.

Comparative X-ray diffraction analysis of 5,6,7,9-tetra-O-acetyl-4,8-anhydro-1,3-dideoxy-D-glycero-L-gluco-nonulose (1) and a structurally related analog, 1,2,3,4,6-penta-O-acetyl-beta-D-galactopyranose (2), are reported. Both crystals have one molecule in the unit cell and the pyranose rings in both exist in the 4C1 conformation.

A sequential per-O-acetylation and thioglycosidation of unprotected reducing sugars using a stoichiometric quantity of acetic anhydride and alkyl- or arylthiols is reported. These reactions, which are catalyzed by BF3.OEt2, together constitute an efficient one-pot method for the synthesis of acetylated thioglycosides.

A convenient one-pot protocol for the direct conversion of acyl-protected carbohydrates into their alkylated counterparts has been developed by using alkyl halides in the presence of solid sodium hydroxide and a phase transfer catalyst. These economically convenient, mild, two-phase reaction conditions allow the preparation of a variety of monosaccharide intermediates for use in the synthesis of complex oligosaccharides.

Alkyl 2,3-unsaturated C-glycopyranosides have been prepared by Ferrier rearrangement of acyl or alkyl protected glycals catalyzed by HClO(4)-SiO(2).

Exchange of acyclic glycosyl dithioacetals to their O,O-acetals has been achieved by a generalized reaction protocol mediated by 1,3-dibromo-5,5-dimethylhydantoin under mild, metal-free and neutral conditions. This methodology has been extended to the synthesis of alkyl glycofuranosides.

An efficient per-O-acetylation of carbohydrates catalyzed by HClO4-SiO2 is reported using a stoichiometric quantity of acetic anhydride avoiding the use of pyridine and excess acetic anhydride under solvent-free conditions.

Unprotected aldose sugars react smoothly with 1,3-diones or beta-ketoesters in the presence of CeCl(3).7H(2)O in aqueous solution to produce polyhydroxylalkyl- and C-glycosylfuran derivatives in excellent yield. Operationally simple, mild neutral reaction conditions in aqueous solution is the key feature of this methodology.

A metal-free, mild, efficient and chemoselective hydrolysis of several thioalkylglycosides (1) into their corresponding 1-hydroxy sugars (2) using sodium N-chloro-p-toluenesulfonamide trihydrate (chloramine-T) without affecting other functional groups is reported.

The disaccharide ethyl 2,4,6-tri-O-acetyl-3-O-(2,3,4,6-tetra-O-benzyl-alpha- D-glucopyranosyl)-1-thio-beta-D-glucopyranoside (6) and methyl 2,6-di-O-benzyl-3-O-(methyl 2,3,4-tri-O-benzyl-alpha-D- glucopyranosyluronate)-beta-D-mannopyranoside (21) have been synthesized and condensed in the presence of methyl triflate to afford a tetrasaccharide derivative. Removal of protecting groups gave methyl 3-O-(methyl alpha-D-glucopyranosyluronate)-4-O-(3-O-alpha-D- glucopyranosyl-beta-D-glucopyranosyl)-beta-D-mannopyranoside (23), the repeating unit of the antigen from Klebsiella type 2, in the form of its methyl ester methyl glycoside.