1,1,2,2-Tetrafluoroethyl-N,N-dimethylamine: a new selective fluorinating agent

6.06 Synthesis of Fluorides

“…In some cases, an S N 1 pathway is observed. 17h Deoxyfluorination and dethiofluorination can be accomplished with several different fluoride sources beyond DAST: pyridinium poly(hydrogen fluoride) (Olah's reagent), 13a,b,13d nitrosonium tetrafluoroborate/pyridinium poly(hydrogen fluoride), 13c triethylamine tris(hydrogen fluoride) (TREAT•HF), 13e perfluoro-1-butanesulfonyl fluoride (PBSF), 19 sulfonyl fluoride/TREAT•HF mixture (Scheme 1), 20 Yarovenko's reagent, 21 Ishikawa's reagent, 22 1,1,2,2-tetrafluoroethyl-N,N-dimethylamine (TFEDMA), 23 N, N′-dimethyl-2,2,-difluoroimidazolidine, 12a 4-morpholinosulfur trifluoride, 11d,24 Deoxo-Fluor®, 11f,25 and 4-tert-butyl-2,6-dimethylphenylsulfur trifluoride. 26 Deoxo-Fluor® is a safer, more thermally stable alternative to DAST but exhibits moisture sensitivity and violent decomposition similar to DAST to generate toxic HF.…”

New types of asymmetrical bromonium salts [RF(RF′)Br]Y where RF and/or RF′ represent perfluorinated aryl, alkenyl, and alkynyl groups

“…When the solution was kept for an additional 60 h at 24 8C, salt 11 was consumed completely and ca. 50% of salt 25 were converted into bromopentafluorobenzene and 1H,1H-octafluoropentan-2-one (26) (Eq. (23)).…”

“…The products C 6 F 13 CH 2 CH 2 F [26], cyclo-1-Br-1,4-C 6 F 7 , and cyclo-1-BrC 6 F 9 [27] were identified by 19 F NMR spectroscopy.…”

A General Approach towards NH‐Pyr­azoles That Bear Diverse Fluoroalkyl Groups by Means of Fluorinated Iminium Salts

“…[48] Generally, these reagents are used as replacements of OH by F in alcohols and carboxylic acids. [49][50][51][52]46,53] Very recently, we became interested in their use as building blocks for the introduction of fluorinated functionalities. [42,43] The key aspect of this methodology relies on the negative hyperconjugation between the lone pairs at nitrogen of the amino group and the adjacent difluoromethylene group.…”