Ionic liquids as solvents of choice for electrophilic fluorination: fluorination of indoles by F-TEDA-BF 4

Mono‐ and Difluorination of Benz­ylic Carbon Atoms

“…N-Alkylated C3-methyl-substituted indoles 6 gave 3-fluoro-3-methyloxindoles [13] 7 in excellent yields when treated with Selectfluor in ionic liquids/alcohol, as shown in Scheme 5. Absence of a substituent at the C3 position leads to difluorinated indoles, as mentioned later in Section B.1.1.…”

Review of ionic liquids with fluorine-containing anions

“…Recent studies on highly selective electrochemical fluorination in ionic liquids fluoride salts were reviewed [72]. A number of recent papers using ionic liquids as solvents for fluorination reactions were reported [73][74][75][76][77][78][79]. Thus, using KF in an ionic liquid enhanced the reactivity of the fluoride ion and improved selectivity [73a] (Scheme 10).…”

Selectfluor: Mechanistic Insight and Applications

“…Recently, the use of ionic liquids, such as triflate, tetrafluoroborate, and phosphorous hexafluoride salts of 1-ethyl-3-methylimidazolium or 1-butyl-3-ethylimidazolium, for reactions with 1 has received attention. [23,24] As reaction efficiencies are higher for many substrates in these reusable and environmentally friendly media, these studies have opened an interesting avenue for further investigation.…”