Systematic study on free radical hydrothiolation of unsaturated monosaccharide derivatives with exo- and endocyclic double bonds

Lázár, László; Csávás, Magdolna; Hadházi, Ádám; Herczeg, Mihály; Tóth, Marietta; Somsák, László; Barna, T.; Herczegh, Pál; Borbás, Anikó

doi:10.1039/c3ob40547h

Cited by 42 publications

(47 citation statements)

References 53 publications

(26 reference statements)

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“…First, 2‐acetamido‐3,4,6‐tri‐ O ‐acetyl‐ d ‐glucal 4 , 2‐acetoxy‐3,4,6‐tri‐ O ‐acetyl‐ d ‐galactal 6 and 2‐acetoxy‐3,4‐di‐ O ‐acetyl‐ l ‐fucal 8 were reacted with thiosugar 2 a under previously established standard conditions (Scheme ). We were pleased to find that all reactions proceeded with exclusive stereoselectivity and in the case of 2‐acetamido‐glucal 4 the expected 1,2‐ cis ‐α‐linked disaccharide 5 was formed in a good yield.…”

Section: Methodsmentioning

confidence: 99%

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Promotion of a Reaction by Cooling: Stereoselective 1,2‐cis‐α‐Thioglycoconjugation by Thiol‐Ene Coupling at −80 °C

Eszenyi

Kelemen

Balogh

et al. 2018

Chemistry A European J

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The photoinitiated thiol-ene coupling reactions of 2-substituted glycals were studied as a generally applicable strategy for stereoselective 1,2-cis-α-thioconjugation. Although all glycals reacted with full α-selectivity, the efficacy of the reactions varied in a broad range depending on their configuration and glycals bearing axial acetoxy substituents reacted with very low efficacy at room temperature. The study revealed that the reaction progress could be promoted by cooling and inhibited by heating. At -80 °C, the equilibrium of the rapidly reversible addition of the thiyl radical to alkenes is shifted almost completely toward products, leading to efficient addition reactions. By exploiting this unique temperature effect a series of α-thio-l-fucosides, -d-galactosides, and d-GlcNAc derivatives were prepared with high efficacy and complete stereoselectivity.

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Section: Methodsmentioning

confidence: 99%

“… Synthesis of 1,2‐ cis ‐α‐ S ‐linked disaccharides from 2‐substituted glycals through photoinduced thiol‐ene coupling under previously established standard conditions …”

Section: Methodsmentioning

confidence: 99%

Promotion of a Reaction by Cooling: Stereoselective 1,2‐cis‐α‐Thioglycoconjugation by Thiol‐Ene Coupling at −80 °C

Eszenyi

Kelemen

Balogh

et al. 2018

Chemistry A European J

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“…exo-or endocyclic double bond within the thiol-ene coupling strategy (Fiore et al, 2009;Lázár et al, 2012Lázár et al, , 2013Staderini et al, 2012), and the inherent potential of this mild and efficient synthetic methodology of a sugar unit incorporation into another bioactive compound through a carbon-sulfur linker has remained unexploited until now.…”

Section: A U T H O R C O P Ymentioning

confidence: 99%

Thio-click approach to the synthesis of stable glycomimetics

et al. 2015

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Carbon-sulfur-bridged glycomimetics were prepared by free radical hydrothiolation of the exocyclic double bond of unsaturated sugars. Reaction between benzoyl-substituted pyranoid-exoglycal and a range of thiols including peptide, 1-thioglycerol and 1-thiosugar derivatives gave β-Dconfigured carbon-sulfur-linked glycoconjugates with full stereoselectivity. Addition of a panel of thiols to a 3-exomethylene-glucofuranose derivative also proceeded in a stereoselective manner and afforded a series of D-allo-configured 3-deoxy-3-C-S-bridged glycoconjugates.

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“…The low yield (13 %) obtained for galactose derivative 15 is presumably due to the less strongly electron‐withdrawing substituents of thiol 14 . We observed earlier that the presence of electron‐donating substituents on the thiol partner reduces its reactivity in the reversible thiol addition reaction 14,15…”

Section: Resultsmentioning

confidence: 99%

Conjugation of Bioactive Molecules to a Fluorescent Dithiomaleimide by Photoinduced and BEt₃‐Initiated Thio‐Click Reactions

et al. 2015

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Two versions of the free‐radical thiol–ene addition, a photoinduced reaction in the presence of 2,2‐dimethoxy‐2‐phenylacetophenone, and a UV‐light‐free hydrothiolation using triethylborane as the initiator, were studied for the conjugation of fluorescent dithiomaleimide to biologically active compounds. A dithiomaleimide derivative bearing a vinyl ether functionality was prepared as the alkene partner. This was coupled with a range of thiols, including thiosugars, captopril, N‐acetyl‐L‐cysteine, and sodium 2‐sulfonatoethanethiol. The Et3B‐initiated method was superior to the photoinduced reaction, as it minimized decomposition of the sensitive maleimide group. The vinyl ether derivative and the addition products showed green light emission in tetrahydrofuran. The compounds all showed almost identical absorption and emission spectra, proving that the structure of the thiols has no influence on the fluorescence properties of the maleimide part of the molecules. The hydrothiolation products showed relatively high quantum yields.

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Systematic study on free radical hydrothiolation of unsaturated monosaccharide derivatives with exo- and endocyclic double bonds

Cited by 42 publications

References 53 publications

Promotion of a Reaction by Cooling: Stereoselective 1,2‐cis‐α‐Thioglycoconjugation by Thiol‐Ene Coupling at −80 °C

Promotion of a Reaction by Cooling: Stereoselective 1,2‐cis‐α‐Thioglycoconjugation by Thiol‐Ene Coupling at −80 °C

Thio-click approach to the synthesis of stable glycomimetics

Conjugation of Bioactive Molecules to a Fluorescent Dithiomaleimide by Photoinduced and BEt₃‐Initiated Thio‐Click Reactions

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Systematic study on free radical hydrothiolation of unsaturated monosaccharide derivatives with exo- and endocyclic double bonds

Cited by 42 publications

References 53 publications

Promotion of a Reaction by Cooling: Stereoselective 1,2‐cis‐α‐Thioglycoconjugation by Thiol‐Ene Coupling at −80 °C

Promotion of a Reaction by Cooling: Stereoselective 1,2‐cis‐α‐Thioglycoconjugation by Thiol‐Ene Coupling at −80 °C

Thio-click approach to the synthesis of stable glycomimetics

Conjugation of Bioactive Molecules to a Fluorescent Dithiomaleimide by Photoin­duced and BEt3‐Initiated Thio‐Click Reactions

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Product

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Conjugation of Bioactive Molecules to a Fluorescent Dithiomaleimide by Photoinduced and BEt₃‐Initiated Thio‐Click Reactions