Studies on the Reaction of D-Glucal and its Derivatives with 1-Chloromethyl-4-Fluoro-1,4-Diazoniabicyclo[2.2.2]Octane Salts

Abstract

ABSTRACT ABSTRACT The reaction of D-glucal and its derivatives with the electrophilic N-F-fluorination reagents F-TEDA tetrafluoroborate and triflate was studied by means of 19F NMR spectroscopy. In all cases mixtures of 2-deoxy-2-fluoro-D-gluco- and -D-mannopyranose derivatives were formed, the ratio of which was dependent on the nature of the O-protecting groups. Concerning the products arising from the direct addition of reagents across the double bond, the D-gluco-configured compounds (13-20) generally showed higher hydrolysis rates than their D-manno-counterparts (21-28). Product separation was only achieved when single anomers (e.g., 2,4-dinitrophenyl glycosides 29e/37e and disaccharidic fluorides 35d/43d) or per-O-acetates (e.g. 29f/37f) were formed.