Glycosyl Cross-Coupling with Diaryliodonium Salts: Access to Aryl C-Glycosides of Biomedical Relevance.

A stereospecific cross-coupling reaction of anomeric nucleophiles with diaryliodonium triflates resulting in the synthesis of aryl C-glycosides is reported. This process capitalizes on a stereoretentive reaction of configurationally stable C1 stannanes and is promoted by a palladium catalyst in the presence of a bulky phosphine ligand that suppresses the undesired β-elimination. The utility of this reaction has been demonstrated in the preparation of a series of C-glycosides derived from common saccharides resulting in exclusive transfer of anomeric configuration from the anomeric nucleophile to the product, and in the synthesis of empagliflozin, a commercial antidiabetic drug.