Results and Problems of <i>O</i>‐Glycoside Synthesis

Wulff, Günter; Röhle, Gerbard

doi:10.1002/anie.197401571

Cited by 308 publications

(69 citation statements)

References 128 publications

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“…The stereoselective formation of the β-glycoside 24 from 23 was mainly caused by participation of the 2-O-benzoyl group of the glycosyl donor 5 through the formation of an acyloxonium ion intermediate. 25 Accordingly, in order to avoid such a neighboring group participation, we sought to introduce an ether substituent for protection of 2-OH of a glycosyl donor. Taking into consideration the available combination of protecting groups employed for the synthetic pathway, PMB and acetyl groups were respectively chosen for protection of 2,3-OH and 4,6-OH.…”

Section: Methodsmentioning

confidence: 99%

Synthetic studies on pterin glycosides: the first synthesis of 2′-O-(α-d-glucopyranosyl)biopterin

et al. 2009

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Section: Methodsmentioning

confidence: 99%

Synthetic studies on pterin glycosides: the first synthesis of 2′-O-(α-d-glucopyranosyl)biopterin

et al. 2009

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“…16 In order to avoid such a neighboring group participation, we sought to introduce an ether substituent for protection of 2-OH of a glycosyl donor. Taking into consideration the available combination of protecting groups employed for the synthetic pathway, p-methoxybenzyl (PMB) and acetyl groups were respectively chosen for protection of 2,3-OH and 4,6-OH of the glycosyl moiety.…”

Section: Methodsmentioning

confidence: 99%

First Synthesis of Biopterin α-D-Glucoside

Hanaya¹,

Baba²,

Yamamoto³

2009

HETEROCYCLES

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(6) with 15 in the presence of silver triflate and tetramethylurea, followed by removal of the protecting groups.Some pterins having a hydroxyalkyl side-chain at C-6, a representative example being biopterin (1), have been found as glycosidic forms in certain prokaryotes; for example, 2'-O-(α-D-glucopyranosyl)biopterin (2) 1-4 isolated from cyanobacteria and limipterin [2'-O-(2-acetamido-2-deoxy-β-D-glucopyranosyl)-biopterin] (3) 5 isolated from a green sulfur photosynthetic bacterium. Glycosides of other pterins such as ciliapterin (L-threo-biopterin), 6 neopterin, 7 and 6-hydroxymethylpterin 8 were also isolated from cyanobacteria, anaerobic photosynthetic bacteria, and chemoautotrophic archaebacteria. Although biopterin α-D-glucoside (2) is the most noteworthy among these pterin glycosides because of its abundant occurrence in various kinds of cyanobacteria, Anacystis nidulans, 1 Oscillatoria sp., 2 Synechococcus sp., 3 and Spirulina platensis, 4 there has been no report for synthesis of 2 since its first discovery in 1958.The physiological function of the parent pterins has been studied in detail: e.g., 1 exhibits enzyme cofactor activity in aromatic amino acid hydroxylation 9 and nitric oxide synthesis 10 as the form of its tetrahydro derivative. By contrast, the functional roles of pterin glycosides have remained obscure, although some inhibitory activities against tyrosinase 11 and photostabilization of photosynthetic pigments 12 were reported for 2. Despite a considerable interest from the viewpoint of their biological activities and functions as well as structural proof of hitherto reported natural products, attempts at preparation of pterin glycosides have scarcely been made so far, except for our synthetic studies on limipterin (3) and ciliapterin glycosides. 13-15In a previous paper, 14 we developed an efficient synthetic protocol for the pterin 2'-O-glycosides by way of the key intermediate, In the present study, we therefore have undertaken to prepare an efficient glycosyl donor leading the preponderant production of pterin α-glycosides. We now describe the first synthesis of the representative, natural pterin glycoside, 2'-O-(α-D-glucopyranosyl)biopterin (2). Scheme 1The stereoselective formation of the β-glycoside (8) from 6 was mainly caused by participation of the 2-O-benzoyl group of the glycosyl donor (7) through the formation of an acyloxonium ion intermediate. 16In order to avoid such a neighboring group participation, we sought to introduce an ether substituent for protection of 2-OH of a glycosyl donor. Taking into consideration the available combination of protecting groups employed for the synthetic pathway, p-methoxybenzyl (PMB) and acetyl groups were respectively chosen for protection of 2,3-OH and 4,6-OH of the glycosyl moiety.Penta-O-acetyl-β-D-glucopyranose (9), 17 derived from D-glucose, served as the starting material for preparation of methyl 4,6-di-O-acetyl-2,3-di-O-PMB-1-thio-β-D-glucopyranose (14) and its α-D-glucopyranosyl bromide derivative (15), the potential glycosyl do...

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“…The beneficial effect of ethereal solvents, 44,45 49 We previously demonstrated that HClO 4 -catalyzed glycosidation with per-O-benzyl-protected glucosyl diphenyl phosphate in dioxane/Et 2 O (1:1) would proceed via a kinetically favored-face attack of an acceptor alcohol on a solvent-separated ion pair, leading to the preferential formation of -glycoside.…”

Section: Mechanistic Aspectsmentioning

confidence: 99%

A stereocontrolled construction of 2-azido-2-deoxy-1,2-cis-α-galactosidic linkages utilizing 2-azido-4,6-O-benzylidene-2-deoxygalactopyranosyl diphenyl phosphates: stereoselective synthesis of mucin core 5 and core 7 structures

Kakita¹,

Tsuda²,

Suzuki³

et al. 2012

Tetrahedron

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TMSOTf-promoted glycosidation of 2-azido-4,6-O-benzylidene-2-deoxygalactosyl diphenyl phosphates with fluorenylmethoxycarbonyl (Fmoc)-protected serine and threonine derivatives in THF/Et2O (1:1) gave glycosyl amino acids in high yields and with excellent levels of α-selectivity (α/β=94:6-95:5). The synthetic utility of the present glycosidation method was demonstrated by a stereoselective synthesis of mucin-type glycopeptide core 5 and core 7 building blocks, which are suitable for Fmoc-based solid-phase synthesis of O-glycopeptides

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Results and Problems of O‐Glycoside Synthesis

Cited by 308 publications

References 128 publications

Synthetic studies on pterin glycosides: the first synthesis of 2′-O-(α-d-glucopyranosyl)biopterin

Synthetic studies on pterin glycosides: the first synthesis of 2′-O-(α-d-glucopyranosyl)biopterin

First Synthesis of Biopterin α-D-Glucoside

A stereocontrolled construction of 2-azido-2-deoxy-1,2-cis-α-galactosidic linkages utilizing 2-azido-4,6-O-benzylidene-2-deoxygalactopyranosyl diphenyl phosphates: stereoselective synthesis of mucin core 5 and core 7 structures

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