Organocatalyzed Direct Glycosylation of Unprotected and Unactivated Carbohydrates

Schmalisch, Sebastian; Mahrwald, Rainer

doi:10.1021/ol402914v

Cited by 37 publications

(16 citation statements)

References 49 publications

(16 reference statements)

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“…Addition of lithium bromide significantly enhanced the yield in acetonitrile medium. The same group in the following year introduced the concept of organo‐catalyzed glycosylation of unprotected and unactivated glycosides . Here, traces of PPh 3 and CBr 4 were used as the catalyst with LiClO 4 as the essential additive.…”

Section: Glycosylationsmentioning

confidence: 99%

Chemical O‐Glycosylations: An Overview

2016

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The development of glycobiology relies on the sources of particular oligosaccharides in their purest forms. As the isolation of the oligosaccharide structures from natural sources is not a reliable option for providing samples with homogeneity, chemical means become pertinent. The growing demand for diverse oligosaccharide structures has prompted the advancement of chemical strategies to stitch sugar molecules with precise stereo‐ and regioselectivity through the formation of glycosidic bonds. This Review will focus on the key developments towards chemical O‐glycosylations in the current century. Synthesis of novel glycosyl donors and acceptors and their unique activation for successful glycosylation are discussed. This Review concludes with a summary of recent developments and comments on future prospects.

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Section: Glycosylationsmentioning

confidence: 99%

Chemical O‐Glycosylations: An Overview

2016

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“…Knowing from previouss tudies that direct access to ribofuranosides from unprotected ribose was not possible in relevant yield, [14,16] we began the study with a5 -O-monoprotected ribose moiety that could be synthesized and wass table at am olar scale, but was still labile enough to be cleaved in situ by simple treatment with acid. Knowing from previouss tudies that direct access to ribofuranosides from unprotected ribose was not possible in relevant yield, [14,16] we began the study with a5 -O-monoprotected ribose moiety that could be synthesized and wass table at am olar scale, but was still labile enough to be cleaved in situ by simple treatment with acid.…”

Section: Resultsmentioning

confidence: 99%

“…The first neutralg lycosylation conditions subjected glucose, in the presence of an excess of phenol,t oM itsunobu conditions to afford the b-phenolic glycoside in moderate yield and reasonabled iastereoselectivity ( Figure 3b). Much more recently, Mahrwald and Schmalisch developed neutral catalytic conditions to provide aliphatic or benzylic glycosides from several furanoses in good to moderate yield; [14] however,g enerallyt he conditions provided am ixture of anomersa nd often the undesired pyranoside regioisomer prevailed. Much more recently, Mahrwald and Schmalisch developed neutral catalytic conditions to provide aliphatic or benzylic glycosides from several furanoses in good to moderate yield; [14] however,g enerallyt he conditions provided am ixture of anomersa nd often the undesired pyranoside regioisomer prevailed.…”

Section: Introductionmentioning

confidence: 99%

Synthesis of Nucleosides through Direct Glycosylation of Nucleobases with 5‐O‐Monoprotected or 5‐Modified Ribose: Improved Protocol, Scope, and Mechanism

Downey

Pohl

Roithová

et al. 2017

Chemistry A European J

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Simplifying access to synthetic nucleosides is of interest due to their widespread use as biochemical or anticancer and antiviral agents. Herein, a direct stereoselective method to access an expansive range of both natural and synthetic nucleosides up to a gram scale, through direct glycosylation of nucleobases with 5-O-tritylribose and other C5-modified ribose derivatives, is discussed in detail. The reaction proceeds through nucleophilic epoxide ring opening of an in situ formed 1,2-anhydrosugar (termed "anhydrose") under modified Mitsunobu reaction conditions. The scope of the reaction in the synthesis of diverse nucleosides and other 1-substituted riboside derivatives is described. In addition, a mechanistic insight into the formation of this key glycosyl donor intermediate is provided.

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“…[64] In the context of organocatalysis, Mahrwald et al reported in 2013 the glycosylation of unprotected sugars using triphenylphosphine and tetrabromomethane under neutral conditions. [65] A series of unprotected monosaccharides (hexoses and D-ribose) were glycosylated with simple alcohols at room temperature. Glycoside products were obtained after 16 h in low to excellent yields and with poor to good α/ stereoselectivity.…”

Section: Organocatalytic Glycosylations Of Unprotected and Unactivatementioning

confidence: 99%

Recent Advances in Organocatalytic Glycosylations

Williams

Galan

2017

Eur J Org Chem

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General rightsThis document is made available in accordance with publisher policies. Please cite only the published version using the reference above. Full terms of use are available: http://www.bristol.ac.uk/pure/about/ebr-terms MICROREVIEW Recent Advances in Organocatalytic GlycosylationsRyan Williams [a] and M. Carmen Galan* [a] Dedication ((optional))Abstract: Carbohydrates play a pivotal role in biological systems and present an opportunity to develop potent carbohydrate derived therapeutics and diagnostic tools for the treatment and detection of disease. To better comprehend the biological functions of carbohydrates, access to pure and structurally defined oligosaccharides is needed. Oligosaccharides are commonly synthesized by chemical means, however, despite progress in glycosylation chemistry, the efficient and stereoselective formation of glycosidic bonds by mild, non-toxic and low-cost methods remains a challenge. Organocatalysis is an exciting field that utilizes small organic molecules to effect chemical transformation where traditionally transition metal catalysis would be required. This microreview presents recent advances in the application of organocatalysis to carbohydrate chemistry and in particular to the stereoselective synthesis of oligosaccharides.

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Organocatalyzed Direct Glycosylation of Unprotected and Unactivated Carbohydrates

Cited by 37 publications

References 49 publications

Chemical O‐Glycosylations: An Overview

Chemical O‐Glycosylations: An Overview

Synthesis of Nucleosides through Direct Glycosylation of Nucleobases with 5‐O‐Monoprotected or 5‐Modified Ribose: Improved Protocol, Scope, and Mechanism

Recent Advances in Organocatalytic Glycosylations

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