TASF reagent
The TASF reagent or trissulfonium difluorotrimethylsilicate is a reagent in organic chemistry with structural formula +−. It is an anhydrous source of fluoride and is used to cleave silyl ether protective groups. Many other fluoride reagents are known, but few are truly anhydrous, because of the extraordinary basicity of "naked" F−. In TASF, the fluoride is masked as an adduct with the weak Lewis acid trimethylsilylfluoride. The sulfonium cation 3S+ is unusually non-electrophilic due to the electron-donating properties of the three 2N substituents.
This compound is prepared from sulfur tetrafluoride:
The colorless salt precipitates from the reaction solvent, diethyl ether.
