130144-05-7

Upstream product

• 74666-83-4 1-deoxy-1-(S-ethyl)-2,3,4,6-tetra-O-benzyl-β-D-glucopyranoside 
• 76375-66-1 methyl 2-O-benzyl-4,6-O-benzylidene-α-D-glucopyranoside 
• 131531-76-5 p-methylphenyl 2,3,4,6-tetra-O-benzyl-thio-β-D-glucopyranoside 
• 38184-10-0 phenyl 2,3,4,5-tetra-O-benzyl-1-thio-β-D-glucopyranoside 
• 74666-83-4 ethyl 2-O-benzoyl-3,4,6-tri-O-benzyl-1-thio-α-D-glucopyranoside 
• 25320-59-6 tetra-O-benzyl glucopyranosyl chloride 
• 78153-79-4 2,3,4,6-tetra-O-benzyl-D-glucopyranosyl fluoride 
• 28244-94-2 p-tolyl-2,3,4,6-tetra-O-acetyl-1-thio-β-D-glucopyranoside 
• 74808-09-6 2,3,4,6-tetra-O-benzyl-α-D-glucopyranosyl trichloroacetimidate 
• 3162-96-7 4,6-O-benzylidene-1-O-methyl-α-D-glucopyranoside 
• 100-39-0 benzyl bromide 
• 28244-94-2 4-methylphenyl 2,3,4,6-tetra-O-acetyl-1-thio-β-D-galactopyranoside 
• 1152-39-2 p-methylphenyl 1-thio-β-D-glucopyranoside 
• 4291-69-4 2,3,4,6-Tetra-O-benzyl-D-glucopyranose 

Relevant academic research and scientific papers

Matching Glycosyl Donor Reactivity to Sulfonate Leaving Group Ability Permits SN2 Glycosylations

Here we demonstrate that highly β-selective glycosylation reactions can be achieved when the electronics of a sulfonyl chloride activator and the reactivity of a glycosyl donor hemiacetal are matched. While these reactions are compatible with the acid- and base-sensitive protecting groups that are commonly used in oligosaccharide synthesis, these protecting groups are not relied upon to control selectivity. Instead, β-selectivity arises from the stereoinversion of an α-glycosyl arylsulfonate in an SN2-like mechanism. Our mechanistic proposal is supported by NMR studies, kinetic isotope effect (KIE) measurements, and DFT calculations.

Ferrocenium complex aided: O-glycosylation of glycosyl halides

A new strategy for the activation of glycosyl halide donors to be utilized in glycosylation reactions is presented, utilizing the ferrocenium (Fc) complexes [FcB(OH)2]SbF6 and FcBF4 as promoters. The scope of the new system has been investigated using glycosyl chloride and glycosyl fluoride donors in combination with common glycosyl acceptors, such as protected glucose. The corresponding glycosylation products were formed in 95 to 10% isolated yields with α/β ratios ranging from 1/1 to β only (2 to 14 h reaction time at room temperature, 40 to 100% ferrocenium promoter load). This journal is

Automated Quantification of Hydroxyl Reactivities: Prediction of Glycosylation Reactions

The stereoselectivity and yield in glycosylation reactions are paramount but unpredictable. We have developed a database of acceptor nucleophilic constants (Aka) to quantify the nucleophilicity of hydroxyl groups in glycosylation influenced by the steric, electronic and structural effects, providing a connection between experiments and computer algorithms. The subtle reactivity differences among the hydroxyl groups on various carbohydrate molecules can be defined by Aka, which is easily accessible by a simple and convenient automation system to assure high reproducibility and accuracy. A diverse range of glycosylation donors and acceptors with well-defined reactivity and promoters were organized and processed by the designed software program “GlycoComputer” for prediction of glycosylation reactions without involving sophisticated computational processing. The importance of Aka was further verified by random forest algorithm, and the applicability was tested by the synthesis of a Lewis A skeleton to show that the stereoselectivity and yield can be accurately estimated.

Solvent-free, under air selective synthesis of α-glycosides adopting glycosyl chlorides as donors

α-Glycosides are highly relevant synthetic targets due to their abundance in natural oligosaccharides involved in many biological processes. Nevertheless their preparation is hampered by several issues, due to both the strictly anhydrous conditions typically required in glycosylation procedures and the non-trivial achievement of high α-stereoselectivity, one of the major challenges in oligosaccharide synthesis. In this paper we report a novel and efficient approach for the highly stereoselective synthesis of α-glycosides. This is based on the unprecedented solvent-free combination of triethylphosphite, tetrabutylammonium bromide and N,N-diisopropylethylamine for the activation of glycosyl chlorides under air. Despite the relative stability of glycosyl chlorides with respect to more reactive halide donors, the solvent-free procedure allowed a wide set of α-glycosides, including biorelevant fragments, to be obtained in much shorter times compared with similar glycosylation approaches in solution. The presented method features a wide target scope and functional group compatibility, also serving with partially disarmed substrates, and it does not require a high stoichiometric excess of reagents nor the preparation of expensive precursors. The solvent-free glycosylation can be even directly performed from 1-hydroxy sugars without purification of the in situ generated chloride, providing an especially useful opportunity in the case of highly reactive and labile glycosyl donors. This journal is

Photo-induced glycosylation using a diaryldisulfide as an organo-Lewis photoacid catalyst

Photo-induced glycosylations of several acceptors with trichloroacetimidate donors using bis(2-naphthyl)disulfide as an organo-Lewis photoacid (LPA) catalyst proceeded effectively to give the corresponding glycosides in good to high yields. In addition, t

Establishment of Guidelines for the Control of Glycosylation Reactions and Intermediates by Quantitative Assessment of Reactivity

Stereocontrolled chemical glycosylation remains a major challenge despite vast efforts reported over many decades and so far still mainly relies on trial and error. Now it is shown that the relative reactivity value (RRV) of thioglycosides is an indicator for revealing stereoselectivities according to four types of acceptors. Mechanistic studies show that the reaction is dominated by two distinct intermediates: glycosyl triflates and glycosyl halides from N-halosuccinimide (NXS)/TfOH. The formation of glycosyl halide is highly correlated with the production of α-glycoside. These findings enable glycosylation reactions to be foreseen by using RRVs as an α/β-selectivity indicator and guidelines and rules to be developed for stereocontrolled glycosylation.

N-Trifluoromethylthiosaccharin/TMSOTf: A New Mild Promoter System for Thioglycoside Activation

For the first time, N-trifluoromethylthiosaccharin was used to activate thioglycosides in the presence of catalytic amounts of TMSOTf. The results show that the activated thioglycosides undergo glycosidation reactions with various glycosyl acceptors to gi

Glycosylation with 3,5-Dimethyl-4-(2′-phenylethynylphenyl)phenyl (EPP) Glycosides via a Dearomative Activation Mechanism

A highly effective and versatile glycosylation method is developed, which uses 3,5-dimethyl-4-(2′-phenylethynylphenyl)phenyl (EPP) glycosides as donors and NIS/TMSOTf as promoter and proceeds via an unprecedented dearomative activation mechanism.

A versatile glycosylation strategy: Via Au(III) catalyzed activation of thioglycoside donors

Among various methods of chemical glycosylations, glycosylation by activation of thioglycoside donors using a thiophilic promoter is an important strategy. Many promoters have been developed for the activation of thioglycosides. However, incompatibility w

Aryl(trifluoroethyl)iodonium Triflimide and Nitrile Solvent Systems: A? Combination for the Stereoselective Synthesis of Armed 1,2-trans-β-Glycosides at Noncryogenic Temperatures

Armed thioglycosides can be activated with aryl(trifluoroethyl)iodonium triflimide in 2:1 CH2Cl2/pivalonitrile or a solvent combination of CH2Cl2, acetonitrile, isobutyronitrile, and pivalonitrile (6:1:1:1) at 0