Addition of Lithiated C-Nucleophiles to 2,3-O-Isopropylidene-d-erythronolactone:  Stereoselective Formation of a Furanose C-Disaccharide

Addition of PhLi and lithiated dithianes to 2,3-O-isopropylidene-d-erythronolactone affords lactols, which are reduced with Et₃SiH to the corresponding C-glycosides, the structures of two of which have been solved by X-ray diffraction. The use of a d-ribose-derived lithiated dithiane nucleophile in this chemistry allows for the convenient construction of a furanose C-disaccharide.