<i>S</i>-Benzoxazolyl as a Stable Protecting Moiety and a Potent Anomeric Leaving Group in Oligosaccharide Synthesis

Kamat, Medha N.; Meo, C. De; Demchenko, Alexei V.

doi:10.1021/jo071191s

Cited by 28 publications

(21 citation statements)

References 54 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…Previously, we demonstrated that SBox leaving group in glycosyl donors 1 and 4 can be efficiently activated over glycosyl acceptor 2 equipped with S-alkyl anomeric moiety (Table 1, entries 1 and 2) or O-pentenyl acceptor 6 (entry 3). 18,20 These glycosylations were promoted by AgOTf, which is a very powerful activator of thioimidates, but is entirely neutral towards thioglycosides or pentenyl glycosides. Resultantly, disaccharides 3 , 5 , and 7 were obtained in nearly quantitative yields.…”

Section: Resultsmentioning

confidence: 99%

On Orthogonal and Selective Activation of Glycosyl Thioimidates and Thioglycosides: Application to Oligosaccharide Assembly

Kaeothip

Demchenko

2011

J. Org. Chem.

Self Cite

View full text Add to dashboard Cite

Discrimination amongst S-thiazolinyl (STaz), S-benzoxazolyl (SBox), and S-ethyl anomeric leaving group was achieved by fine-tuning of the activation conditions. Preferential glycosidation of a certain leaving group is neither determined by the strength of activating reagents nor the stability of the leaving group itself; instead, the type of activation comes to the fore and plays the key role. The activation conditions established herein were applied to a sequential five-step synthesis of a hexasaccharide using six monosaccharide building blocks equipped with six different leaving groups.

show abstract

Section: Resultsmentioning

confidence: 99%

On Orthogonal and Selective Activation of Glycosyl Thioimidates and Thioglycosides: Application to Oligosaccharide Assembly

Kaeothip

Demchenko

2011

J. Org. Chem.

Self Cite

View full text Add to dashboard Cite

show abstract

“…Therefore, glycosyl thioimidates containing different protecting groups can be prepared readily. [95] Unprotected hexofuranosyl thioimidates were also prepared X. Zhu and R. R. Schmidt Reviews and found application in the synthesis of the corresponding glycosyl phosphates [96] and hexofuranosides. [97] Thioimidate donors can withstand reaction conditions associated with the activation of other glycosyl donors, such as thioglycosides, glycosyl bromides, and O-glycosyl trichloroacetimidates; thioimidates themselves can be activated selectively in the presence of thioglycosides and n-pentenyl glycosides (NPGs).…”

Section: Glycosyl Thioimidatesmentioning

confidence: 99%

New Principles for Glycoside‐Bond Formation

2009

View full text Add to dashboard Cite

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.

show abstract

“…146,147 SBox glycosyl donor 114 was selectively activated over the SEt acceptor 82 in the presence of AgOTf to produce disaccharide 162 in 99% yield. The latter disaccharide was glycosidated with the n -pentenyl acceptor 163 in the presence of MeOTf.…”

Section: Multistep Sequences Based On Selective Activationsmentioning

confidence: 99%

Expeditious oligosaccharide synthesis via selective, semi-orthogonal, and orthogonal activation

Kaeothip

Demchenko

2011

Carbohydrate Research

Self Cite

View full text Add to dashboard Cite

Traditional strategies for oligosaccharide synthesis often require extensive protecting and/or leaving group manipulations between each glycosylation step, thereby increasing the total number of synthetic steps while decreasing the efficiency of the synthesis. In contrast, expeditious strategies allow for the rapid chemical synthesis of complex carbohydrates by minimizing extraneous chemical manipulations. Oligosaccharide synthesis by selective activation of one leaving group over another is one such expeditious strategy. Herein, the significant improvements that have recently emerged in the area of the selective activation are discussed. The development of orthogonal strategy further expands the scope of the selective activation methodology. Surveyed in this article, are representative examples wherein these excellent innovations have been applied to the synthesis of various oligosaccharide sequences.

show abstract

S-Benzoxazolyl as a Stable Protecting Moiety and a Potent Anomeric Leaving Group in Oligosaccharide Synthesis

Cited by 28 publications

References 54 publications

On Orthogonal and Selective Activation of Glycosyl Thioimidates and Thioglycosides: Application to Oligosaccharide Assembly

On Orthogonal and Selective Activation of Glycosyl Thioimidates and Thioglycosides: Application to Oligosaccharide Assembly

New Principles for Glycoside‐Bond Formation

Expeditious oligosaccharide synthesis via selective, semi-orthogonal, and orthogonal activation

Contact Info

Product

Resources

About