Tris(dimethylamino)sulfonium Difluorotrimethylsilicate

Good Partnership between Sulfur and Fluorine: Sulfur-Based Fluorination and Fluoroalkylation Reagents for Organic Synthesis

“…Compared to the aforementioned sulfur-based deoxygenative fluorination reagents, tris­(dimethylamino)­sulfonium difluorotrimethylsilicate (TASF) is a highly nucleophilic and so-called “naked” fluoride ion source with a bulky noncoordinating sulfonium counterion, which can be prepared through the reaction of SF 4 with 3 equiv of (dimethylamino)­trimethylsilane in a rigorously anhydrous form . Since its introduction by Middleton in 1976, TASF has become an excellent fluorination reagent for the preparation of alkyl fluorides, as well as a versatile activating agent in many transformations . For example, in a recent report, TASF was used for the efficient synthesis of 4-fluorinated glutamines, such as 20 , from the corresponding tosylates, such as 19 .…”

Synthesis of Optically Pure 4-Fluoro-Glutamines as Potential Metabolic Imaging Agents for Tumors

“…Similarly, the bimolecular cyclization could be the reason for the formation of dimer 21 . Finally, the use of another hypervalent silicon fluorination agent, tris(dimethylamino) sulfonium difluorotrimethylsilicate (TASF), gave significantly improved yields (entry 10) . The yield was further improved (to 60−70%) (entry 11) by adding TASF in two portions at a 12-h interval.…”

TASF Fluorination for Preparing Alkyl Fluorides

“…The acronym TASF was originally used for both tris(dimethylamino)sulfonium salts and tris(diethylamino)sulfonium salts. Today, TASF refers more often to tris(dimethylamino)sulfonium salt, due to the commercial availability, higher purity, and the advantages of easy formation of crystalline solid, although the ethyl version has better solubility in organic solvents [18][19][20].…”

“…Various applications have been found since this reagent was invented, including the generation of enolates from silyl enol ethers, and the enolates can be used for new C-C bond formation reactions and polymer formation (group transfer polymerization), cross-coupling reactions, cycloadditions, and generation of unusual carbanions, as well as mild and efficient fluoride sources for deprotection of sensitive silyl protecting groups [18][19][20]. This chapter will focus on the application of TASF as an anhydrous fluoride ion source.…”

“…TASF has proved to be an efficient nucleophilic fluorination agent due to its anhydrous status and good solubility in organic solvents. The syntheses of varied fluorinated sugar analogs were reported during the early stages of utilizing this fluorination reagent [18][19][20], while the syntheses of fluorinated amino acids have only been reported recently [17,23].…”