Diverse Synthesis of C-Glycosides by Stereoselective Ni-Catalyzed Carboboration of Glycals

Journal of the American Chemical Society, Journal Year: 2024, Volume and Issue: 146(28), P. 18866 - 18872

Published: July 5, 2024

C-Glycosides are important structures that common to natural products and pharmaceutical agents. Established methods for their synthesis involve the reaction of an activated anomeric carbon. In this study, we report a conceptually new approach involves stereoselective Ni-catalyzed carboboration glycals. these reactions, not only is C–C bond formed at carbon, but synthetically useful C–B also installed. Upon oxidation, differentially protected C-glycosides be formed. addition, stereospecific manipulation leads diverse C-glycosides. Finally, application method in established C-glycosides, such as C-glycosyl amino acids, well strategy make all possible diastereomers C1 C2.

Language: Английский

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The Multiple Roles of Bipyridine-Nickel(II) Complex in Versatile Photoredox C(sp²)–C(sp³) Cross-Coupling

ACS Catalysis, Journal Year: 2025, Volume and Issue: unknown, P. 3328 - 3338

Published: Feb. 9, 2025

Language: Английский

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NHC-mediated photocatalytic para-selective C–H acylation of aryl alcohols: regioselectivity control via remote radical spiro cyclization

Science China Chemistry, Journal Year: 2025, Volume and Issue: unknown

Published: Jan. 14, 2025

Language: Английский

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Unveiling Heavier Dihydropyridine Chalcogenol Esters in Metallaphotoredox Catalyst-Enabled Regioselective Hydrothio(seleno)carbonylation

Organic Letters, Journal Year: 2025, Volume and Issue: unknown

Published: Jan. 23, 2025

Herein, aromaticity-driven thio(seleno)ester group transfer from novel 1,4-dihydropyridine thio(seleno)esters to alkene feedstocks is disclosed by merging palladium and photoredox catalysis. In this process, photoactivation of dihydropyridine integrated with regioselective hydrometalation alkenes, avoiding photoinduced Pd-C bond homolysis organopalladium intermediates. Additionally, a hydroselenocarbonylation an accomplished for the first time using bench-stable selenoester reagent. The activation mode thioesters has been illustrated detailed mechanistic studies, spectroscopic analysis, intermediate trapping, isotope labeling experiments.

Language: Английский

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One-Pot Stereoselective Synthesis of C-Glycosyl Amino Acids with Vicinal Stereocenters

Organic Letters, Journal Year: 2025, Volume and Issue: unknown

Published: April 10, 2025

A palladium-catalyzed cascade coupling between glycals and racemic α-nitroesters enables the stereoselective construction of C-glycosyl amino acids bearing two contiguous stereocenters, achieving dual stereocontrol (exclusive β-C1, up to 10:1 diastereomeric ratio at C7). This one-pot protocol room temperature accommodates diverse substrates (25 examples). Mechanistic studies demonstrate that decarboxylation-induced C4-oxyanion directs 1,4-syn selectivity, while steric modulation governs C7 stereochemistry. Synthetic versatility is evidenced by gram-scale synthesis late-stage functionalization trihydroxy C-glycosides, 2,3-dideoxy sugars, 4-O-amino acid conjugates.

Language: Английский

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Electrochemical Glycosylation via Halogen-Atom-Transfer for C-Glycoside Assembly

ACS Catalysis, Journal Year: 2024, Volume and Issue: 14(15), P. 11532 - 11544

Published: July 19, 2024

Glycosyl donor activation emerged as an enabling technology for anomeric functionalization, but aimed primarily at O-glycosylation. In contrast, we herein disclose mechanistically distinct electrochemical glycosyl bromide activations via halogen-atom transfer and C-glycosylation. The radical addition to alkenes led C-alkyl glycoside synthesis under precious metal-free reaction conditions from readily available bromides. robustness of our e-XAT strategy was further mirrored by C-aryl C-acyl glycosides assembly through nickela-electrocatalysis. Our approach provides orthogonal with expedient scope, hence representing a general method direct C-glycosides assembly.

Language: Английский

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C–OH Bond Activation for Stereoselective Radical C-Glycosylation of Native Saccharides

Journal of the American Chemical Society, Journal Year: 2024, Volume and Issue: 146(47), P. 32269 - 32275

Published: Nov. 15, 2024

Radical C-glycosylation presents a flexible and efficient method for synthesizing C-glycosides. Existing methods always require multistep processes generating anomeric radicals. In this study, we introduce streamlined approach to produce radicals through direct C-OH bond homolysis of unmodified saccharides, eliminating the need protection, deprotection, or activation steps. These selectively couple with activated alkenes, yielding products high stereoselectivity (>20:1). This is applicable variety native monosaccharides, such as l-arabinose, d-arabinose, d-xylose, l-xylose, d-galactose, β-d-glucose, α-d-glucose, l-ribose, well oligosaccharides including α-lactose, d-(+)-melibiose, acarbose. We also extend amino acid peptide derivatives, demonstrate synthesis an anti-inflammatory agent.

Language: Английский

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Stereoselective Construction of Multifunctional C-Glycosides Enabled by Nickel-Catalyzed Tandem Borylation/Glycosylation

Journal of the American Chemical Society, Journal Year: 2024, Volume and Issue: 146(32), P. 22413 - 22423

Published: Aug. 3, 2024

Stereochemically pure saccharides have indispensable roles in fields ranging from medicinal chemistry to materials science and organic synthesis. However, the development of a simple, stereoselective, efficient glycosylation protocol access α- β-C-glycosides (particularly 2-deoxy entities) remains persistent challenge. Existing studies primarily focused on C1 modification carbohydrates transformation glycosyl radical precursors. Here, we innovate by harnessing situ generated glycosyl-Ni species achieve one-pot borylation cascade manner, which is enabled an earth-abundant nickel-catalyzed carboboration readily accessible glycals without any ligand. This work reveals potential for modular multifunctional platform facilitate simultaneous introduction C-C C-B bonds at stereogenic center saccharides, largely unexploited research area. Preliminary experimental computational indicate that endocyclic O C3 group play important stereoseclectively forging glycosidic bonds. As result, diverse range C-R (R = alkyl, aryl, alkenyl) 2-deoxygenated glycosides bearing modifiable boron groups could be rapidly made with excellent stereocontrol exhibit remarkable functional tolerance. The synthetic underscored late-stage natural products commercial drugs as well facile preparation various rare sugars, bioactive conjugates, key intermediates prorocentin, phomonol, aspergillide A.

Language: Английский

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Late-Stage Glycosylation of Peptides by Methionine-Directed β-C(sp³)–H Functionalization with 1-Iodoglycals

Organic Letters, Journal Year: 2024, Volume and Issue: 26(34), P. 7128 - 7133

Published: Aug. 19, 2024

Using l-methionine (Met) as the endogenous directing group, we developed Pd-catalyzed β-C(sp3)–H glycosylation of peptides with 1-iodoglycals. A wide range tri- to hexapeptides containing Ala-Met motifs underwent Ala C–H under standard conditions give glycopeptides smoothly. 15 proteinogenic amino acids (with easily removable protecting groups) were well tolerated. Control experiments indicated that Met acted a N,S-bidentate group and exhibited an effect superior other acid residues such l-aspartic (Asp), l-asparagine (Asn), S-protected l-cysteine (Cys). In addition, further transformation by HFIP-promoted 1,4-elimination furnished another type glycopeptide 1,3-diene motif, which provides handle for derivatization.

Language: Английский

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Direct construction of aryl amide N-glycosides from glycosyl oxamic acids via photoredox palladium-catalyzed aminocarbonylations

Chem Catalysis, Journal Year: 2024, Volume and Issue: unknown, P. 101109 - 101109

Published: Sept. 1, 2024

Language: Английский

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