S-(4-methoxyphenyl) benzenethiosulfinate (MPBT)/trifluoromethanesulfonic anhydride: a convenient system for the generation of glycosyl triflates from thioglycosides.

[structure] The combination of S-(4-methoxyphenyl) benzenethiosulfinate (MPBT, 1) and trifluoromethanesulfonic anhydride forms a powerful, metal-free, thiophile which readily activates thioglycosides, via glycosyl triflates, at -60 degrees C in dichloromethane, in the presence of 2,6-di-tert-butyl-4-methylpyridine. The glycosyl triflates are rapidly and cleanly converted to glycosides, upon treatment with alcohols, in good yield and selectivity.