Total Syntheses of Conjugation-Ready Repeating Units of Acinetobacter baumannii AB5075 for Glycoconjugate Vaccine Development

Acinetobacter baumannii is an opportunistic pathogen that causes serious nosocomial infections. One of the multidrug-resistant strains, AB5075, can result in bacteremia, pneumonia and wound infections associated with high morbidity and mortality. The structurally unique glycans on the surface of these bacteria are attractive targets for the development of glycoconjugate vaccines. Here, we report the first total synthesis of the densely functionalized trisaccharide repeating unit of A. baumannii AB5075 as well as two analogues. The construction of 1,2-cis linkages between the rare sugars relies on a double-serial inversion strategy. The judicious selection of building blocks and reaction conditions allowed for stereoselective glycosylations, the installation of acetamido groups and the (S)-3-hydroxybutanoyl chain.     

Alkyne Aminopalladation/Heck and Suzuki Cascades: An Approach to Tetrasubstituted Enamines

Alkyne aminopalladation reactions starting from tosylamides are reported. The emerging vinylic Pd species are converted either in an intramolecular Heck reaction with olefinic units or in an intermolecular Suzuki reaction by using boronic acids exhibiting broad functional group tolerance. Tetra(hetero)substituted tosylated enamines are obtained in a simple one-pot process.     

Zur Reinigung des Fluorammoniums

Ohne Zusammenfassung     

Die Bestimmung des Zuckers

Ohne Zusammenfassung