A potential glucuronate glycosyl donor with 2-O-acyl-6,3-lactone structure: efficient synthesis of glycosaminoglycan disaccharides

Furukawa, Takayuki; Hinou, Hiroshi; Shimawaki, Ken; Nishimura, Shin‐Ichiro

doi:10.1016/j.tetlet.2011.08.024

Cited by 14 publications

(20 citation statements)

References 47 publications

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“…[16] In contrast to the common perception that the C-5 carboxylic acid ester is a strongly electron-withdrawing ("disarming") substituent, we found that in the β-manno series the C-5-carboxylate group (in combination with a 4-O-acetyl group) was in fact less disarming than the 4,6-O-benzylidene functionality. We currently have no adequate explanation for the reluctance of donor 1 to react with NIS/ TfOH, and note that this result is in contrast with a recent study reported by Furukawa et al, [18] who investigated glucuronic acid 3,6-lactone donors in combination with this activator; they reported that thiophenyl 2,4-di-O-acetylglucuronic acid 3,6-lactone donors are reactive glucuronylating species when activated with NIS/TfOH, and that its 2,4-di-O-benzyl counterpart was too reactive to be used as a donor. In the vast majority of competition experiments performed to date, thioglycoside donors have been combined with the N-iodosuccinimide (NIS)/triflic acid (TfOH) activator system.…”

Section: Resultscontrasting

confidence: 94%

On the Reactivity and Selectivity of Galacturonic Acid Lactones

et al. 2012

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The reactivity and stereoselectivity of a galacturonic acid 3,6‐lactone thioglycosyl donor, previously described as a highly reactive glycosylating agent, has been investigated by using a series of competition experiments and condensation reactions with different thiophilic activator systems. It is revealed that the relative reactivity of the thioglycosides depends on the activator system used and that p‐nitrophenylsulfenyl triflate shows overall attenuated reactivity differences with respect to the commonly used N‐iodosuccinimide/triflic acid promoter system. With respect to the stereoselectivity of the studied galacturonic acid 3,6‐lactone thioglycosyl donor, it is revealed that a preactivation‐based glycosylation system gives rise to α‐selective glycosylation, whereas an in situ activation protocol leads to the formation of the β‐product with good selectivity. It is hypothesized that these opposingstereoselectivities are the result of different product‐forming intermediates. Where preactivation of the donor leads to the formation of an intermediate β‐triflate, which is substituted in a concerted fashion to provide the α‐product, a 3H4 oxocarbenium ion like species is substituted in the in situ activation experiment to provide the β‐linked product.

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Section: Resultscontrasting

confidence: 94%

On the Reactivity and Selectivity of Galacturonic Acid Lactones

et al. 2012

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“…Our previous studies utilized carboxybenzyl (CB) donors which require pre‐activation; therefore, we prepared thioglycoside derivatives 9 , 10 , and 11 to investigate whether glycosylations under standard (pre‐mix) conditions would prevent 1,4‐anhydrosugar formation. Glycosylation of 9 – 10 by pre‐activation with Ph 2 SO/Tf 2 O, followed by addition of glycosyl acceptor 7 (Table , entries 1,3, and 5), mainly led to 1,4‐anhydrosugar as expected . Galactoside 11 does not suffer from 1,4‐anhydrosugar formation as the C‐4 benzyl is positioned equatorially and afforded the α‐galactoside with excellent stereoselectivity ( α / β =20/1, Table , entry 5), in line with earlier reports .…”

Section: Methodssupporting

confidence: 88%

The Glycosylation Mechanisms of 6,3‐Uronic Acid Lactones

Elferink¹,

Mensink²,

Castelijns³

et al. 2019

Angew Chem Int Ed

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Uronic acids are important constituents of polysaccharides found on the cell membranes of different organisms. To prepare uronic‐acid‐containing oligosaccharides, uronic acid 6,3‐lactones can be employed as they display a fixed conformation and a unique reactivity and stereoselectivity. Herein, we report a highly β‐selective and efficient mannosyl donor based on C‐4 acetyl mannuronic acid 6,3‐lactone donors. The mechanism of glycosylation is established using a combination of techniques, including infrared ion spectroscopy combined with quantum‐chemical calculations and variable‐temperature nuclear magnetic resonance (VT NMR) spectroscopy. The role of these intermediates in glycosylation is assayed by varying the activation protocol and acceptor nucleophilicity. The observed trends are analogous to the well‐studied 4,6‐benzylidene glycosides and may be used to guide the development of next‐generation stereoselective glycosyl donors.

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Section: Methodssupporting

confidence: 88%

The Glycosylation Mechanisms of 6,3‐Uronic Acid Lactones

Elferink¹,

Mensink²,

Castelijns³

et al. 2019

Angewandte Chemie

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Uronic acids are important constituents of polysaccharides found on the cell membranes of different organisms. To prepare uronic-acid-containing oligosaccharides,u ronic acid 6,3-lactones can be employed as they displayaf ixed conformation and au nique reactivity and stereoselectivity. Herein, we report ah ighly b-selective and efficient mannosyl donor based on C-4 acetyl mannuronic acid 6,3-lactone donors.T he mechanism of glycosylation is established using ac ombination of techniques,i ncluding infrared ion spectroscopyc ombined with quantum-chemical calculations and variable-temperature nuclear magnetic resonance (VT NMR) spectroscopy. The role of these intermediates in glycosylation is assayed by varying the activation protocol and acceptor nucleophilicity.T he observed trends are analogous to the well-studied 4,6-benzylidene glycosides and mayb eu sed to guide the development of next-generation stereoselective glycosyl donors.

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A potential glucuronate glycosyl donor with 2-O-acyl-6,3-lactone structure: efficient synthesis of glycosaminoglycan disaccharides

Cited by 14 publications

References 47 publications

On the Reactivity and Selectivity of Galacturonic Acid Lactones

On the Reactivity and Selectivity of Galacturonic Acid Lactones

The Glycosylation Mechanisms of 6,3‐Uronic Acid Lactones

The Glycosylation Mechanisms of 6,3‐Uronic Acid Lactones

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