A General Approach to 1,2-trans-C-Glycosides via Glycosyl Samarium(III) Compounds

A remarkable stereoselective coupling reaction is undergone by glycosyl pyridyl sulfones, such as 1, with carbonyl compounds affording 1,2-trans-C-glycosides. In contrast to the corresponding lithium counterparts the intermediate anomeric organosamarium reagent displays enhanced stability to β elimination of the C2-substituent.