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

Addition of PhLi and lithiated dithianes to 2,3-<i>O</i>-isopropylidene-d-erythronolactone affords lactols, which are reduced with Et₃SiH to the corresponding <i>C</i>-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 <i>C</i>-disaccharide.