Bimodal glycosyl donors as an emerging approach towards a general glycosylation strategy

Chemistry - A European Journal, Journal Year: 2024, Volume and Issue: 30(29)

Published: March 19, 2024

Organic synthesis provides an accessible route to preparative scale biological glycans, although schemes access these complex structures are often complicated by preparation of multiple monosaccharide building blocks. Bimodal glycosyl donors capable forming both α- and β-anomers selectively, emerging tactic reduce the required number individual synthetic components in glycan construction. This review discusses examples bimodal literature, how they achieve their stereocontrol for anomers. Notable include a bespoke O-2 benzyl protecting group, strained glycal reaction using organometallic catalysis, simple perbenzylated donor optimised stereoselective glycosylation through extensive tuning.

Language: Английский

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Stereoselective Synthesis of β-S-Glycosides via Palladium Catalysis

The Journal of Organic Chemistry, Journal Year: 2024, Volume and Issue: 89(12), P. 8815 - 8827

Published: June 5, 2024

S-Glycosides are more resistant to enzymatic and chemical hydrolysis exhibit higher metabolic stability than common O-glycosides, demonstrating their widespread application in biological research drug development. In particular, β-S-glycosides used as antirheumatic, anticancer, antidiabetic drugs clinical practice. However, the stereoselective synthesis of is still highly challenging. Herein, we report an effective β-S-glycosylation using 3-O-trichloroacetimidoyl glycal thiols under mild conditions. The C3-imidate designed guide Pd form a complex with glucal from upper face, followed by Pd–S (thiols) coordination realize β-stereoselectivity. This method demonstrates excellent compatibility broad scope various thiol acceptors donors yields up 87% β/α ratio 20:1. present strategy for late-stage functionalization drugs/natural products such estrone, zingerone, thymol. Overall, this novel simple operation approach provides general practical construction β-thioglycosides, which holds high potential discovery

Language: Английский

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Stereoselective Synthesis of Glycosides via Tsuji–Trost Type Glycosylation Using 3,4‐Carbonate Galactals

The Chemical Record, Journal Year: 2024, Volume and Issue: 24(9)

Published: Aug. 21, 2024

Pd-catalyzed stereoselective glycosylations using unsaturated sugar derivatives, glycals, have been successfully achieved in recent years. This review focuses on approaches to control the stereoselectivities of glycosides via π-allyl intermediates that mimic Tsuji-Trost asymmetric allylic alkylation reactions, enabling stereoselectivity through rational design. In reaction process, zwitterionic Pd-π-allyl complexes, formed after oxidative addition and decarboxylation, play a crucial role increasing reactivities enhancing α- β-glycosides. We summarized recently developed type 3,4-carbonate galactals, featuring high efficiency, exclusive stereoselectivities, broad scope including O-, N-, S-, C-glycosylations.

Language: Английский

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Synthesis of Seven-Membered Ring Nucleosides and Serendipitous Simmons–Smith O-Glycosylation

Organic Letters, Journal Year: 2024, Volume and Issue: 26(24), P. 5187 - 5191

Published: June 12, 2024

A series of seven-membered (oxepine) nucleosides containing various nucleobases (A, U, T, 5-FU, C) were synthesized by ring expansion cyclopropanated glucals. We expect this new ring-expanded nucleic acid analogues to be useful as building blocks in the design mixed base functional genetic systems. While exploring alternative pathways oxepine nucleoside synthesis, we discovered an unprecedented α-stereoselective

Language: Английский

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Hydrogenation of Sugar Enol-Ethers Using Pd/Et₃SiH Reagent System: A Route to Deoxy Sugars/Glycosides

The Journal of Organic Chemistry, Journal Year: 2024, Volume and Issue: unknown

Published: Dec. 16, 2024

We have developed a hydrogenation method using Pd(OAc)2/Et3SiH as reagent system for sugar enol ethers and their glycosides. This approach is highly effective applicable to wide range of glycals glycosides, achieving yields up 96% the corresponding deoxy sugars. Applying standard conditions various O/C-glycosides resulted in excellent transformation 2,3-dideoxy

Language: Английский

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Highly Regio-/Stereoselective Synthesis of Carbohydrates with Unsaturated Glycosyl Donors under Mild Conditions

Synlett, Journal Year: 2024, Volume and Issue: unknown

Published: June 19, 2024

Abstract Carbohydrates and their conjugates play important roles in life activities drug development. Our group was committed to the general effective glycosylation methods application chemical biology using unsaturated glycosyl donors. In past five years, we have reported several synthetic strategies with high stereoselectivity milder conditions compared previous works. particular, chemo-/regio- stereoselective O-glycosylation, C-glycosylation S-glycosylation could be achieved via palladium catalysis under open-air at room temperature. this Account, will introduce our research progress constructing four types of glycosides. 1 Introduction 2 Stereoselective Synthesis O-Glycosides 3 C-Glycosides 4 N-Glycosides 5 S-Glycosides 6 Conclusion

Language: Английский

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