Physical properties
R = Me, mp 98–101 °C; R = Et, mp 90–95 °C.
Uses
Tris(dimethylamino)sulfonium
Difluorotrimethylsilicate is used in anhydrous fluoride ion source; synthesis of C–F compounds by
nucleophilic displacement of sulfonates;promoter for electrophilic reactions of silyl enolates of ketones and esters; source
of sulfonium cation capable of stabilizing or imparting high
nucleophilic reactivity to other anions; activator of vinylsilanes in Pd-catalyzed cross-coupling reactions; also used for
generation8 and reactions of α- and β-halo carbanions; hydrosilylation and cyanomethylation of ketones.
Uses
Tris(dimethylamino)sulfonium difluorotrimethylsilicate (TASF
2SiMe
3) can be used as a mild deprotecting reagent for the cleavage of silicon protecting groups.
It can also be used
- To synthesize deoxyfluoro sugars by reacting with trifluoromethanesulfonyl derivatives of partially protected sugars.
- As a reagent for the fluorination of hydroxyl-containing compounds.
Preparation
The methyl derivative is prepared by
the reaction of dimethylaminotrimethylsilane and sulfur tetra-
fluoride at ?70°C to rt in ether; the precipitated solid is
filtered off.1a The ethyl derivative is best prepared by the
reaction of N,N-diethylaminosulfur trifluoride (DAST) and
diethylaminotrimethylsilane.
General Description
Tris(dimethylamino)sulfonium difluorotrimethylsilicate is widely used in organic synthesis as a source of fluoride ion for the synthesis of fluorinated compounds by C-F bond formation. It is also used as a reagent in hydrosilylation, cyanomethylation of ketones and Pd-catalyzed cross-coupling reactions.
