Synthesis of glycosyl fluorides from thio-, seleno-, and telluroglycosides and glycosyl sulfoxides using aminodifluorosulfinium tetrafluoroborates

[Display omitted] ► Xtalfluor-E and -M convert thio-, seleno-, and telluroglycosides to glycosyl fluorides. ► Reaction occurs readily without need for additional NBS. ► Sulfoxides are also converted to glycosyl fluorides. ► Mechanistic support delivery of fluoride from tetrafluoroborate counterion. Glycosyl fluorides can be synthesized from thio-, seleno-, and telluroglycosides and glycosyl sulfoxides using the aminodifluorosulfinium tetrafluoroborate reagents Xtalfluor-E and -M, with or without added N-bromosuccinimide. Mechanistic studies provide evidence that fluoride is delivered from the tetrafluoroborate counterion.