ChemInform Abstract: THE AZIDONITRATION OF TRI‐O‐ACETYL‐D‐GALACTAL

Lemieux, R. U.; Ratcliffe, R. M.

doi:10.1002/chin.197940306

Cited by 10 publications

(14 citation statements)

References 1 publication

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“…25 α-Selectivity is commonly observed in galactal reactions, and it is attributed to the anomeric effect and the pseudoaxial disposition of the C4-OAc. 11 BAIB is the source for the acetoxy moiety in acetyl glycoside 8. Side products bearing acetoxy groups were observed in the presence of BAIB in the azidophenylselenylation of olefins, where acetoxyphenylsenelyl compounds were identified.…”

Section: ■ Results and Discussionmentioning

confidence: 99%

Safe and Scalable Continuous Flow Azidophenylselenylation of Galactal to Prepare Galactosamine Building Blocks

Guberman

Pieber

Seeberger

2019

Org. Process Res. Dev.

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Differentially protected galactosamine building blocks are key components for the synthesis of human and bacterial oligosaccharides. The azidophenylselenylation of 3,4,6-tri-O-acetyl-D-galactal provides straightforward access to the corresponding 2-nitrogenated glycoside. Poor reproducibility and the use of azides that lead to the formation of potentially explosive and toxic species limit the scalability of this reaction and render it a bottleneck for carbohydrate synthesis. Here, we present a method for the safe, efficient, and reliable azidophenylselenylation of 3,4,6-tri-O-acetyl-D-galactal at room temperature, using continuous flow chemistry. Careful analysis of the transformation resulted in reaction conditions that produce minimal side products while the reaction time was reduced drastically when compared to batch reactions. The flow setup is readily scalable to process 5 mmol of galactal in 3 h, producing 1.2 mmol/h of product.

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Section: ■ Results and Discussionmentioning

confidence: 99%

Safe and Scalable Continuous Flow Azidophenylselenylation of Galactal to Prepare Galactosamine Building Blocks

Guberman

Pieber

Seeberger

2019

Org. Process Res. Dev.

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“…Lemieux et al employed a classical azidonitration method for synthesis of 2-azido sugars, especially those which may serve as precursors to glycosamines but are inaccessible from nature. 164 However, despite the high regioselectivity of this reaction, a mixture of epimers 34 and 35 was observed in varying ratios based on the employed glycal substrate 33 (Scheme 12). 165 The prepared nitropyranoses 34 and 35 may find significance in preparation of numerous carbohydrate-based halides, thioglycosides, etc.…”

Section: Azides and Alkyne Substrates: Benefit For Carbohydratesmentioning

confidence: 98%

Cu-Catalyzed Click Reaction in Carbohydrate Chemistry

et al. 2016

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Cu(I)-catalyzed azide-alkyne 1,3-dipolar cycloaddition (CuAAC), popularly known as the "click reaction", serves as the most potent and highly dependable tool for facile construction of simple to complex architectures at the molecular level. Click-knitted threads of two exclusively different molecular entities have created some really interesting structures for more than 15 years with a broad spectrum of applicability, including in the fascinating fields of synthetic chemistry, medicinal science, biochemistry, pharmacology, material science, and catalysis. The unique properties of the carbohydrate moiety and the advantages of highly chemo- and regioselective click chemistry, such as mild reaction conditions, efficient performance with a wide range of solvents, and compatibility with different functionalities, together produce miraculous neoglycoconjugates and neoglycopolymers with various synthetic, biological, and pharmaceutical applications. In this review we highlight the successful advancement of Cu(I)-catalyzed click chemistry in glycoscience and its applications as well as future scope in different streams of applied sciences.

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“…Treating the bromide with a sugar acceptor 14 in the presence of sym-collidine and 4 Å molecular sieves in benzene afforded the resulting disaccharide 15 in 38% yield (Scheme 4). The utility of glycosyl bromides was further demonstrated by Takeuchi, Umezawa, and co-workers in their synthesis of 2hydroxyaclacinomycin A (18). 49 In this approach, the requisite trideoxysaccharide was converted into the corresponding bromide 16 by treatment with Tf 2 O in the presence of Et 4 NBr.…”

Section: Glycosyl Halidesmentioning

confidence: 99%

Methods for 2-Deoxyglycoside Synthesis

2018

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Deoxy-sugars often play a critical role in modulating the potency of many bioactive natural products. Accordingly, there has been sustained interest in methods for their synthesis over the past several decades. The focus of much of this work has been on developing new glycosylation reactions that permit the mild and selective construction of deoxyglycosides. This Review covers classical approaches to deoxyglycoside synthesis, as well as more recently developed chemistry that aims to control the selectivity of the reaction through rational design of the promoter. Where relevant, the application of this chemistry to natural product synthesis will also be described.

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ChemInform Abstract: THE AZIDONITRATION OF TRI‐O‐ACETYL‐D‐GALACTAL

Abstract: Reaktion des Galactals (I) mit NaN3 und dem Nitratocerat (II) liefert die Azidonitrate (IIIa)‐(IIIc), deren Gemisch bei der Chromatographie an Silicagel′in Skellysolve B/Ac‐OH als Solvens unter Hydrolyse das α‐D‐Galactopyranosylamin (IIId) gibt.

Cited by 10 publications

References 1 publication

Safe and Scalable Continuous Flow Azidophenylselenylation of Galactal to Prepare Galactosamine Building Blocks

Safe and Scalable Continuous Flow Azidophenylselenylation of Galactal to Prepare Galactosamine Building Blocks

Cu-Catalyzed Click Reaction in Carbohydrate Chemistry

Methods for 2-Deoxyglycoside Synthesis

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