Remote Activation of Disarmed Thioglycosides in Latent-Active Glycosylation via Interrupted Pummerer Reaction

Xiao, Xiong; Zhao, Yueqi; Shu, Penghua; Zhao, Xin; Liu, Yan; Sun, Jiuchang; Zhang, Qian; Zeng, Jing; Wan, Qian

doi:10.1021/jacs.6b08305

Cited by 64 publications

(30 citation statements)

References 81 publications

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“…Further elaboration of 51 continued with ag lycosylation using building block 42 to furnish protected disaccharide 52 in 93 %y ield. TheN ap ether was removed as preparation for another glycosylation with building block 41 to yield protected trisaccharide 54.Removal of the benzylidene acetal on 54 proved challenging.T reatment with (+ +)-camphor-10-sulfonic acid as ac atalyst and ethanethiol as acetal exchange reagent [44,45] gave trisaccharide diol 55 in low yield. Instead, aqueous acetic acid (80 %) at 60 8 8Cs moothly delivered 55 in 87 %y ield (Supporting Information).…”

Section: Methodsmentioning

confidence: 99%

Discovery of Oligosaccharide Antigens for Semi‐Synthetic Glycoconjugate Vaccine Leads against Streptococcus suis Serotypes 2, 3, 9 and 14**

et al. 2021

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Streptococcus suis bacteria are one of the most serious health problems for pigs and an emerging zoonotic agent in humans working in the swine industry. S. suis bacteria express capsular polysaccharides (CPS) a major bacterial virulence factor that define the serotypes. Oligosaccharides resembling the CPS of S. suis serotypes 2, 3, 9, and 14 have been synthesized, glycans related to serotypes 2 and 9 were placed on glycan array surfaces to screen blood from infected pigs. Lead antigens for the development of semi‐synthetic S. suis serotypes 2 and 9 glycoconjugate veterinary vaccines were identified in this way.

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Section: Methodsmentioning

confidence: 99%

Discovery of Oligosaccharide Antigens for Semi‐Synthetic Glycoconjugate Vaccine Leads against Streptococcus suis Serotypes 2, 3, 9 and 14**

et al. 2021

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“…to obtain disaccharide 68 (Scheme 15), which, in turn, was activated via the iterative Sonogashira coupling to derivative 69 and subjected to the glycosylation sequence to afford trisaccharide 70. The problem associated with the disarmed donor in this method was resolved by introducing a new thioglycoside, namely, S-2-(2-propylsulfinyl)benzyl (SPSB) glycoside as a glycosyl donor that was efficiently activated in a tandem remote mode [39]. The SPSB glycoside was synthesized from the corresponding S-2-(2propylthio)benzyl (SPTB) glycoside by oxidation.…”

Section: (Iv) Latent-active Glycosylationsmentioning

confidence: 99%

One-pot oligosaccharide synthesis: latent-active method of glycosylations and radical halogenation activation of allyl glycosides

Pal

Das

Jayaraman

2019

Pure and Applied Chemistry

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Chemical glycosylations occupy a central importance to synthesize tailor-made oligo- and polysaccharides of functional importance. Generation of the oxocarbenium ion or the glycosyl cation is the method of choice in order to form the glycosidic bond interconnecting a glycosyl moiety with a glycosyl/aglycosyl moiety. A number of elegant methods have been devised that allow the glycosyl cation formation in a fairly stream-lined manner to a large extent. The latent-active method provides a powerful approach in the protecting group controlled glycosylations. In this context, allyl glycosides have been developed to meet the requirement of latent-active reactivities under appropriate glycosylation conditions. Radical halogenation provides a newer route of activation of allyl glycosides to an activated allylic glycoside. Such an allylic halide activation subjects the glycoside reactive under acid catalysis, leading to the conversion to a glycosyl cation and subsequent glycosylation with a number of acceptors. The complete anomeric selectivity favoring the 1,2-trans-anomeric glycosides points to the possibility of a preferred conformation of the glycosyl cation. This article discusses about advancements in the selectivity of glycosylations, followed by delineating the allylic halogenation of allyl glycoside as a glycosylation method and demonstrates synthesis of a repertoire of di- and trisaccharides, including xylosides, with varied protecting groups.

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“…Episulfonium ion Q, which was observed by HRMS, subsequently hydrolyzed into compounds 3g and 3h. 20…”

Section: Account Syn Lettmentioning

confidence: 99%

Interrupted Pummerer Reaction in Latent/Active Glycosylation

Meng

Zeng

Wan

2017

Synlett

Self Cite

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A latent/active glycosylation strategy is efficient for rapid assembly of oligosaccharides. We recently developed novel OPTB/OPSB and SPTB/SPSB glycosides as two pairs of latent/active glycosyl donors. The active OPSB and SPSB glycosyl donors are efficiently activated by Tf2O via an interrupted Pummerer reaction mechanism. In this account, the design, developments, mechanism studies and applications of these new glycosylation methodologies are described.1 Introduction2 Conceiving Ideas3 Synthesis of OPSB and SPSB Glycosides4 Substrate Scope5 Application in the Synthesis of Natural Products6 Conclusion

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Remote Activation of Disarmed Thioglycosides in Latent-Active Glycosylation via Interrupted Pummerer Reaction

Cited by 64 publications

References 81 publications

Discovery of Oligosaccharide Antigens for Semi‐Synthetic Glycoconjugate Vaccine Leads against Streptococcus suis Serotypes 2, 3, 9 and 14**

Discovery of Oligosaccharide Antigens for Semi‐Synthetic Glycoconjugate Vaccine Leads against Streptococcus suis Serotypes 2, 3, 9 and 14**

One-pot oligosaccharide synthesis: latent-active method of glycosylations and radical halogenation activation of allyl glycosides

Interrupted Pummerer Reaction in Latent/Active Glycosylation

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