Search

In this work, the synthetic utility of the Ferrier reaction to access S-linked disaccharides and S-linked glycoamino acids has been probed. Significantly, entry to a range of 1,4- and 1,6-S-linked disaccharides has been achieved using glycals derived from glucose and galactose, and sulfur containing coupling partners derived from methyl α-d-glucopyranoside. Access to S-linked glycoamino acids and glycopeptides has also been achieved using protected cysteine and homocysteine coupling partners within the Ferrier reaction. Functionalisation of the Ferrier products, for example, via dihydroxylation using OsO4 or amino acid coupling, and deprotection of the targets have also been achieved. In this way, entry to materials of interest as mimics of biologically interesting disaccharides and glycopeptides has been realised, including targets derived from rare sugars such as talopyranose and gulopyranose.

The synthesis of disaccharides containing α-linked GlcNAc or β-linked ManNAc units from shelf-stable, and yet highly reactive, 2-oximinoglycosyl donors is described. Access to a preponderance of the disaccharides containing either the α-linked GlcNAc or β-linked ManNAc unit can be obtained by careful choice of solvent and glycosidation conditions.

A review of methods available for the polymer supported syntheses of oligosaccharides and glycopeptides is presented. The range of polymers and linkers, oligosaccharide assembly strategies, and analytical techniques employed in recent syntheses are described.

The application of Lipase enzymes to effect regioselective C-3-O-acylation of 4,6-O- benzylidene -β- d - gluco - and -galactopyranosides displaying a range of anomeric substituents, and C-2-O-acylation of phenyl 4,6-O- benzylidene -α- d - glucopyranoside and ethyl 4,6-O- benzylidene-1-thio -α- d - glucopyranoside is reported. In particular this method has allowed introduction of a variety of acyl protecting groups at the C-3 hydroxyl group of ethyl 4,6-O- benzylidene-1-thio -β- d - glucopyranoside 11.

Monochiral N -Diphenyphosphinyl aziridines ( ‘N- Dpp aziridines’ ) may efficiently be prepared from monochiral 2-aminoalcohols. Such aziridines undergo ring-opening reaction with a variety of nucleophiles in good yield. Dephosphinylation is accomplished under mild conditions.