1-Benzenesulfinyl piperidine/trifluoromethanesulfonic anhydride: A potent combination of shelf-stable reagents for the low-temperature conversion of thioglycosides to glycosyl triflates and for the formation of diverse glycosidic linkages

The combination of 1-benzenesulfinyl piperidine (BSP) and trifluoromethanesulfonic anhydride (Tf2O) forms a new, powerful, metal-free thiophile that can readily activate both armed and disarmed thioglycosides, via glycosyl triflates, in a matter of minutes at -60 degreesC in dichloromethane, in the presence of 2,4,6-tri-tert-butylpyrimidine (TTBP). The glycosyl triflates are rapidly and cleanly converted to glycosides, upon treatment with alcohols, in good yield and selectivity.