Glycosyl thioimidates as versatile building blocks for organic synthesis

Hasty, Scott J.; Demchenko, Alexei V.

doi:10.1007/s10593-012-0984-4

Cited by 23 publications

(20 citation statements)

References 80 publications

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“…This derivative was first introduced for glycosylation by Mukaiyama et al . In 2011, Hasty and Demchenko introduced another variant of thioglycoside donor, S‐benzimidazolyl (SBiz) glycosides, 85 (Figure ), suitable for extensive oligosaccharide synthesis …”

Section: Glycosylationsmentioning

confidence: 99%

Chemical O‐Glycosylations: An Overview

2016

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The development of glycobiology relies on the sources of particular oligosaccharides in their purest forms. As the isolation of the oligosaccharide structures from natural sources is not a reliable option for providing samples with homogeneity, chemical means become pertinent. The growing demand for diverse oligosaccharide structures has prompted the advancement of chemical strategies to stitch sugar molecules with precise stereo‐ and regioselectivity through the formation of glycosidic bonds. This Review will focus on the key developments towards chemical O‐glycosylations in the current century. Synthesis of novel glycosyl donors and acceptors and their unique activation for successful glycosylation are discussed. This Review concludes with a summary of recent developments and comments on future prospects.

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Section: Glycosylationsmentioning

confidence: 99%

Chemical O‐Glycosylations: An Overview

2016

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“…Over the last decade, we have been interested in syntheses and applications of various glycosyl thioimidates as new, versatile building blocks for chemical glycosylation and expeditious oligosaccharide synthesis. 32 S-Benzoxazolyl (SBox), 33 S-thiazolinyl (STaz), 34 O-methyl phenylcarbamothioate (SNea), 35 and S-benzimidazolyl (SBiz) 36 are all commonly activated with AgOTf. This activation pathway often gives superior yields and stereoselectivity, compared against those achieved with other activators.…”

Section: Resultsmentioning

confidence: 99%

A study of silver (I) perchlorate as an effective promoter for chemical glycosylation with thioimidates and thioglycosides

Hasty¹,

Ranade²,

Demchenko³

2014

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It has been previously acknowledged that perchlorate salts may be beneficial for the formation of 1,2-cis glycosides. Here, we demonstrate the effectiveness of silver (I) perchlorate as a powerful promoter of glycosyl thioimidate activation. Improved 1,2-cis selectivity was obtained, compared against that obtained with other silver (I) salts, including commonly-used triflate. The use of a combination of silver (I) perchlorate and methyl sulfenyl bromide to activate thioglycosides was also investigated. The cooperative use of these activation protocols was applied to a one-pot, two-step sequential activation, using thioimidate and thioglycoside building blocks.

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“…In both cases, the authors demonstrated that benzoxazolyl 1-thio-β-D-glucopyranoside (GlcSBox) and benzimidazolyl 1-thio-β-D-glucopyranoside (GlcSBiz) hydrolyses were catalysed by remote activation of the C-S bond through protonation of the ring nitrogen in the aglycone. Such remote activation was also described in the case of Araf51 [15], which was able to use similar arabinofuranosyl thioimidates as glycosyl donors in thioglycoligation reaction [29][30][31][32][33][34][35]. In the context of chemoenzymatic synthesis of glycosides, these substrates are attractive because of their high stability towards chemical hydrolysis in aqueous solutions, as well as efficient leaving group ability [15].…”

Section: Introductionmentioning

confidence: 89%

Hydrolysis of Glycosyl Thioimidates by Glycoside Hydrolase Requires Remote Activation for Efficient Activity

et al. 2019

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Chemoenzymatic synthesis of glycosides relies on efficient glycosyl donor substrates able to react rapidly and efficiently, yet with increased stability towards chemical or enzymatic hydrolysis. In this context, glycosyl thioimidates have previously been used as efficient donors, in the case of hydrolysis or thioglycoligation. In both cases, the release of the thioimidoyl aglycone was remotely activated through a protonation driven by a carboxylic residue in the active site of the corresponding enzymes. A recombinant glucosidase (DtGly) from Dictyoglomus themophilum, previously used in biocatalysis, was also able to use such glycosyl thioimidates as substrates. Yet, enzymatic kinetic values analysis, coupled to mutagenesis and in silico modelling of DtGly/substrate complexes demonstrated that the release of the thioimidoyl moiety during catalysis is only driven by its leaving group ability, without the activation of a remote protonation. In the search of efficient glycosyl donors, glycosyl thioimidates are attractive and efficient. Their utility, however, is limited to enzymes able to promote leaving group release by remote activation.

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Glycosyl thioimidates as versatile building blocks for organic synthesis

Cited by 23 publications

References 80 publications

Chemical O‐Glycosylations: An Overview

Chemical O‐Glycosylations: An Overview

A study of silver (I) perchlorate as an effective promoter for chemical glycosylation with thioimidates and thioglycosides

Hydrolysis of Glycosyl Thioimidates by Glycoside Hydrolase Requires Remote Activation for Efficient Activity

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