Stereoretentive Conversion to -Glycosides from -Glycosides via Ligand-Coupling on Sulfur(IV).

A novel strategy is reported for the stereoselective synthesis of C(sp)-C(sp) -glycosides, which converts heteroaryl -glycosides into heteroaryl -glycosides with retention of configuration through a sequential process involving oxidation and Grignard reagent attack. The new method involves the generation of a S(IV) intermediate, followed by ligand coupling of the glycosyl and heteroaryl groups to yield heteroaryl -glycosides. The diverse heteroaryl -glycosides were achieved with good efficiency.