Lewis acid catalysed direct glycosylation of N-acetyl-D-glucosamine

Scoponi, Giulia (2017) Lewis acid catalysed direct glycosylation of N-acetyl-D-glucosamine. [Laurea magistrale], Università di Bologna, Corso di Studio in Chimica industriale [LM-DM270], Documento ad accesso riservato.
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Abstract

Incorporation of the relevant monosaccharide N-Acetyl-D-glucosamine (GlcNAc) into synthetic oligosaccharides by chemical glycosylation is still a very challenging object of studies, since direct reactions are low yielding. This issue is generally ascribed to its low solubility in common solvents and to the formation of a poorly reactive oxazoline intermediate, which is typically bypassed by introducing extra synthetic steps to avoid the presence of the NHAc moiety during glycosylation. Recently, a new direct Lewis acids-catalysed GlcNAc-ylation protocol has been disclosed, with acylated donors appearing to hold potential for high yielding glycosylation reactions. This master project focused indeed on a novel synthesis of promising 1-acyl GlcNAc donors, in order to test them in direct Lewis acid catalysed glycosylation without the need of N-protecting groups. Screening of various Lewis acids and reaction conditions with these acylated donors has been carried out, in presence of reactive primary alcohols as well as more challenging carbohydrate acceptor alcohols. These experiments demonstrated that the fine tuning of the leaving group combined with a suitable metal triflate could lead to a successful reaction outcome in the direct glycosylation. Successful methodology of this kind would provide rapid access to naturally occurring N-glycan motifs, such as the highly relevant human milk oligosaccharides (HMOs).

Abstract
Tipologia del documento
Tesi di laurea (Laurea magistrale)
Autore della tesi
Scoponi, Giulia
Relatore della tesi
Correlatore della tesi
Scuola
Corso di studio
Ordinamento Cds
DM270
Parole chiave
direct GlcNAc-ylation N-acetil glucosamine catalytic glycosylation GlcNAc metal triflates catalysis Lewis acids human milk holigosaccharides
Data di discussione della Tesi
11 Ottobre 2017
URI

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