Glycosylation Through Intramolecular Aglycon Delivery

Fairbanks, A. J.

doi:10.1016/b978-0-12-409547-2.14950-9

Cited by 3 publications

(2 citation statements)

References 90 publications

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“…Although the construction of α-mannosyl linkages can be achieved by neighboring group participation or through the exploitation of stereoelectronic effects, the β-linkage of mannoside is challenging to construct stereoselectively [215]. Well-established methodologies for β-mannoside synthesis include direct glycosylation with 4,6-O-benzylidene protected donors [216][217][218][219][220][221][222] and indirect methodologies, including intramolecular aglycon delivery (IAD) [156,[223][224][225][226][227][228][229], intermolecular H-bond-mediated aglycone delivery [230], stereochemical inversion of βgluco or β-galacto glycosides [231][232][233][234][235], and anomeric O-alkylations [236].…”

Section: Bimodal Glycosyl Donor Approach For Application To 12-cis α-...mentioning

confidence: 99%

Recent Progress in 1,2-cis glycosylation for Glucan Synthesis

et al. 2023

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Controlling the stereoselectivity of 1,2-cis glycosylation is one of the most challenging tasks in the chemical synthesis of glycans. There are various 1,2-cis glycosides in nature, such as α-glucoside and β-mannoside in glycoproteins, glycolipids, proteoglycans, microbial polysaccharides, and bioactive natural products. In the structure of polysaccharides such as α-glucan, 1,2-cis α-glucosides were found to be the major linkage between the glucopyranosides. Various regioisomeric linkages, 1→3, 1→4, and 1→6 for the backbone structure, and 1→2/3/4/6 for branching in the polysaccharide as well as in the oligosaccharides were identified. To achieve highly stereoselective 1,2-cis glycosylation, including α-glucosylation, a number of strategies using inter- and intra-molecular methodologies have been explored. Recently, Zn salt-mediated cis glycosylation has been developed and applied to the synthesis of various 1,2-cis linkages, such as α-glucoside and β-mannoside, via the 1,2-cis glycosylation pathway and β-galactoside 1,4/6-cis induction. Furthermore, the synthesis of various structures of α-glucans has been achieved using the recent progressive stereoselective 1,2-cis glycosylation reactions. In this review, recent advances in stereoselective 1,2-cis glycosylation, particularly focused on α-glucosylation, and their applications in the construction of linear and branched α-glucans are summarized.

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Section: Bimodal Glycosyl Donor Approach For Application To 12-cis α-...mentioning

confidence: 99%

Recent Progress in 1,2-cis glycosylation for Glucan Synthesis

et al. 2023

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“…In order to get the 1,2-cis glycoside, stereospecifically, the procedure based on intramolecular aglycon delivery (IAD) (Barresi and Hindsgaul, 1991) (recent reviews, Ishiwata and Ito, 2017;Ishiwata, 2019;Fairbanks, 2021) is still one of the most promising methodologies despite the initial tethering between the glycosyl donor and acceptor residues before the intramolecular glycosidic bond formation reaction. However, a two-step procedure can precisely control the approach of the oxygen atom of the hydroxy group in the acceptor residue which was linked as the mixed acetal to the donor residue.…”

Section: Recent Examples Using Intramolecular Coupling For 12-cis Gly...mentioning

confidence: 99%

Recent advances in stereoselective 1,2-cis-O-glycosylations

Ishiwata

Tanaka

et al. 2022

Front. Chem.

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For the stereoselective assembly of bioactive glycans with various functions, 1,2-cis-O-glycosylation is one of the most essential issues in synthetic carbohydrate chemistry. The cis-configured O-glycosidic linkages to the substituents at two positions of the non-reducing side residue of the glycosides such as α-glucopyranoside, α-galactopyranoside, β-mannopyranoside, β-arabinofuranoside, and other rather rare glycosides are found in natural glycans, including glycoconjugate (glycoproteins, glycolipids, proteoglycans, and microbial polysaccharides) and glycoside natural products. The way to 1,2-trans isomers is well sophisticated by using the effect of neighboring group participation from the most effective and kinetically favored C-2 substituent such as an acyl group, although high stereoselective synthesis of 1,2-cis glycosides without formation of 1,2-trans isomers is far less straightforward. Although the key factors that control the stereoselectivity of glycosylation are largely understood since chemical glycosylation was considered to be one of the useful methods to obtain glycosidic linkages as the alternative way of isolation from natural sources, strictly controlled formation of these 1,2-cis glycosides is generally difficult. This minireview introduces some of the recent advances in the development of 1,2-cis selective glycosylations, including the quite recent developments in glycosyl donor modification, reaction conditions, and methods for activation of intermolecular glycosylation, including the bimodal glycosylation strategy for 1,2-cis and 1,2-trans glycosides, as well as intramolecular glycosylations, including recent applications of NAP-ether-mediated intramolecular aglycon delivery.

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ZnI2-Mediated cis-Glycosylations of Various Constrained Glycosyl Donors: Recent Advances in cis-Selective Glycosylations

Ishiwata,

Zhong,

Tanaka

et al. 2024

Molecules

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An efficient and versatile glycosylation methodology is crucial for the systematic synthesis of oligosaccharides and glycoconjugates. A direct intermolecular and an indirect intramolecular methodology have been developed, and the former can be applied to the synthesis of medium-to-long-chain glycans like that of nucleotides and peptides. The development of a generally applicable approach for the stereoselective construction of glycosidic bonds remains a major challenge, especially for the synthesis of 1,2-cis glycosides such as β-mannosides, β-L-rhamnosides, and β-D-arabinofuranosides with equatorial glycosidic bonds as well as α-D-glucosides with axial ones. This review introduces the direct formation of cis-glycosides using ZnI2-mediated cis-glycosylations of various constrained glycosyl donors, as well as the recent advances in the development of stereoselective cis-glycosylations.

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Glycosylation Through Intramolecular Aglycon Delivery

Cited by 3 publications

References 90 publications

Recent Progress in 1,2-cis glycosylation for Glucan Synthesis

Recent Progress in 1,2-cis glycosylation for Glucan Synthesis

Recent advances in stereoselective 1,2-cis-O-glycosylations

ZnI2-Mediated cis-Glycosylations of Various Constrained Glycosyl Donors: Recent Advances in cis-Selective Glycosylations

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