Oligosaccharide assembly by one-pot multi-step strategy

Wang, Yuhang; Ye, Xin‐Shan; Zhang, Lihe

doi:10.1039/b704586g

Cited by 144 publications

(80 citation statements)

References 83 publications

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“…[40] The above strategies and progress in the field are discussed in that article and in other relevant reviews. [60,263] Generally, two or three different glycosidic linkages are constructed in a one-pot process based on these procedures.…”

Section: One-pot Glycosylationmentioning

confidence: 97%

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New Principles for Glycoside‐Bond Formation

2009

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Increased understanding of the important roles that oligosaccharides and glycoconjugates play in biological processes has led to a demand for significant amounts of these materials for biological, medicinal, and pharmacological studies. Therefore, tremendous effort has been made to develop new procedures for the synthesis of glycosides, whereby the main focus is often the formation of the glycosidic bonds. Accordingly, quite a few review articles have been published over the past few years on glycoside synthesis; however, most are confined to either a specific type of glycoside or a specific strategy for glycoside synthesis. In this Review, new principles for the formation of glycoside bonds are discussed. Developments, mainly in the last ten years, that have led to significant advances in oligosaccharide and glycoconjugate synthesis have been compiled and are evaluated.

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Section: One-pot Glycosylationmentioning

confidence: 97%

“…[40] In combination with computational tools, this technique has been further developed into a programmable one-pot synthesis. [41] Solid-phase oligosaccharide synthesis is also an area of active investigation, [42] as it enables the rapid assembly of structures of interest with only a single purification step necessary (Section 5).…”

Section: Introductionmentioning

confidence: 99%

New Principles for Glycoside‐Bond Formation

2009

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“…In fact, the sequential glycosylation reactions are performed in a single flask (pot) and do not require isolation and purification of the intermediates. Many variations of the one-pot strategy have been developed (63,71,72,(94)(95)(96)(97)(98)(99)(100)(101)(102) …”

Section: E Innovative Technologies For Oligosaccharide Synthesismentioning

confidence: 99%

From Stereocontrolled Glycosylation to Expeditious Oligosaccharide Synthesis

Yasomanee

Demchenko

2013

TIGG

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“…1,2 But such is the biological importance of carbohydrates 3 that solutions for many of these difficulties are on the horizon, for example through 'one-pot' glycosylations using orthogonally activated donors [4][5][6] and the advent of solid phase automated oligosaccharide synthesis. 1,[7][8][9][10] Despite these advances, however, stereocontrol over the formation of the glycosidic linkage still remains a challenge, particularly in the synthesis of 1,2-cis glycosides.…”

Section: Introductionmentioning

confidence: 99%

Stereoselective glycosylations using oxathiane spiroketal glycosyl donors

Fascione

Webb

Kilner

et al. 2012

Carbohydrate Research

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Novel oxathiane spiroketal donors have been synthesised and activated via an umpolung Sarylation strategy using 1,3,5-trimethoxybenzene and 1,3-dimethoxybenzene.The comparative reactivity of the resulting 2,4,6-trimethoxyphenyl (TMP)-and 2,4-dimethoxyphenyl (DMP)-oxathiane spiroketal sulfonium ions is discussed, and theirstereoselectivity in glycosylation reactions are compared to the analogous TMP-and DMPsulfonium ions derived from a oxathiane glycosyl donors bearing a methyl ketal group. The results show that the stereoselectivity of the oxathiane glycosyl donors is dependent on the structure of the ketal group and reactivity can be tuned by varying the substituent on the sulfonium ion. IntroductionThe chemical synthesis of complex oligosaccharides presents many technical challenges ranging from lengthy reaction sequences through to problematic purification steps. Scheme 1 a) Umpolung S-arylation strategy for oxathiane ketal-S-oxide donors 1. b)Oxathiane ketal donor scaffold 4 and oxathiane spiroketal donor scaffold 6.Attempts to arylate glycosyl oxathianes with benzyne led to the formation of glycosyl 3 acetates. 21 However, oxidation of the oxathiane to give oxathiane ketal-S-oxides 1, and subsequent treatment with Tf 2 O, led to the formation of surprisingly stable activated intermediates which were sufficiently long-lived to undergo electrophilic aromatic substitution in the presence 1,3,5-trimethoxybenzene (TMB). Therefore, conversion of the previously nucleophilic sulfide into an electrophilic S(IV) centre facilitated an "umpolung" approach to S-arylation. The resulting 2,4,6-trimethoxyphenyl (TMP)-oxathiane ketal sulfonium ions 2 then afforded -glycosides 3 with complete stereoselectivity following heating at 50 °C. However, although glycosylation reactions with oxathiane ketal sulfonium ions 4 are notable for the formation of glycosides with complete -stereoselectivity, 19,21 the resulting O-2 acyclic ketal formed in the product 5 occasionally decomposed under the reaction conditions, diminishing yields in more challenging glycosylation reactions.Therefore, in an attempt to circumvent this issue, we set out to design a new oxathiane donor scaffold in which the axial methoxy group was replaced with an O-substituent constrained in a spirocyclic ring (Scheme 1b). It was anticipated that following glycosylation, spiroketal sulfonium ion 6 would afford glycosides 7 bearing an O-2 cyclic ketal which would be more stable than the corresponding O-2 acyclic ketal, but still sufficiently labile to be removed by Lewis acid catalysed cleavage. To this end, we present the synthesis and activation of oxathiane spiroketal-S-oxides via an umpolung S-arylation strategy, and compare theirstereoselectivities in glycosylation reactions with the analogous oxathiane ketal sulfoniumions. We also demonstrate that the stability and -stereoselectivity of oxathiane spiroketal sulfonium ions in glycosylation reactions can be modulated by changing the S-aryl appendage exogenous to the oxathiane ring. Both TMP and 2,4-dimet...

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Oligosaccharide assembly by one-pot multi-step strategy

Cited by 144 publications

References 83 publications

New Principles for Glycoside‐Bond Formation

New Principles for Glycoside‐Bond Formation

From Stereocontrolled Glycosylation to Expeditious Oligosaccharide Synthesis

Stereoselective glycosylations using oxathiane spiroketal glycosyl donors

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