Cyclophellitol and cyclophellitol aziridine are potent and irreversible inhibitors of retaining β‐glucosidases. They preferentially adopt a 4H3 half‐chair conformation, thereby mimicking the... Show moreCyclophellitol and cyclophellitol aziridine are potent and irreversible inhibitors of retaining β‐glucosidases. They preferentially adopt a 4H3 half‐chair conformation, thereby mimicking the substrate‐transition‐state conformation characteristic of retaining β‐glucosidases. As a consequence, both compounds bind tightly to the enzyme active site, and attack of the catalytic nucleophile onto the epoxide/aziridine results in enzyme deactivation. Replacement of the epoxide oxygen in cyclophellitol by a (substituted) carbon yielded carba‐cyclophellitols, a conceptually new class of inhibitors of retaining β‐glucosidases, as we demonstrated in a recent communication. In this paper, in‐depth synthetic studies of this class of compounds are described, and the preparation of a comprehensive set of structurally and configurationally new carba‐cyclophellitols is presented. Show less
This Thesis reports on research aimed at the assembly of acidic and zwitterionic polysaccharides of bacterial origin, using suitably protected 1-thioglycoside residues. Thioglycosides are... Show moreThis Thesis reports on research aimed at the assembly of acidic and zwitterionic polysaccharides of bacterial origin, using suitably protected 1-thioglycoside residues. Thioglycosides are attractive monosaccharide building blocks because of their high stability towards the diverse reaction conditions used in functional group manipulations. Recently, the use of 1-thioglycosides has been stimulated by the advent of the 1-benzenesulfinylpiperidine (BSP)/triflic anhydride (Tf2O) and the diphenylsulfoxide (Ph2SO)/Tf2O activator system. These sulfonium ion based activators proved to be efficient promoters for glycosylations in which inreactive (disarmed) 1-thioglycosides are employed. Furthermore, one-pot orthogonal and chemoselective oligosaccharide synthesis strategies that involve the use of 1-thioglycosides in combination with the above mentioned sulfonium based activator systems have proven to be feasible. Show less
