CARBOHYDRATE-CHEMISTRY OF THE ANOMERIC CARBON-SULFUR BOND

Aryl and alkyl S-glycosides and sulfones are ideal precursors of three classes of reactive intermediates : anomeric carbenium, anion, and ra dical, and thus play a remarkable role in carbohydrate chemistry of th e anomeric carbon atom. Reported reactions will include : A conceptual ly novel glycosylation reaction based on the activation of thioglycosi des by a one electron -transfer reagent. Uses of a novel class of glyc osyl donors : anomeric S-xanthates of 2-azido sugars. Selective synthe sis of alpha and beta C-glycosides using anomeric reductive lithiation or reductive samariation of phenyl S-glycosides or sulfones. Convenie nt synthesis of substituted pyranoid glycals. Expeditious synthesis of C-disaccharides by SmI2 induced intramolecular coupling reaction of t ethered glycosyl phenyl sulfone and exomethylene sugar.