FeCl3·6H2O/C: An Efficient and Recyclable Catalyst for the Synthesis of 2,3-Unsaturated O- and S-Glycosides

A novel method for synthesizing 2,3-unsaturated glycosides has been developed using a handy and eco-friendly immobilized catalyst, FeCl3·6H2O/C. A series of 2,3-unsaturated O- and S-glycosides were obtained for bioassay from corresponding 3,4,6-tri-O-acetyl-D-glucal and D-galactal in good to excellent yields (56%–99%) and high anomeric selectivity (α/β = 7:1 to >19:1). Furthermore, the catalyst was efficient on gram-scale reactions and recyclable for at least three times.