Halogenation of Primary Alcohols Using a Tetraethylammonium Halide/[Et₂NSF₂]BF₄ Combination

Abstract

The halogenation of primary alcohols is presented. The use of a combination of tetraethylammonium halide and [Et(2)NSF(2)]BF(4) (XtalFluor-E) allows for chlorination and bromination reactions to proceed efficiently (up to 92% yield) with a wide range of alcohols. Iodination reactions are also possible albeit in lower yields.

Dialkylaminodifluorosulfinium Salts: XtalFluor-E and XtalFluor-M

“…When compound 2 was used instead of compound 1, substrate decomposition was observed. 6 Chlorination, bromination and iodination reaction of primary alcohols in good yield has been described using a combination of tetraethylammonium halide and XtalFluor-E. 7 Fuchs and co-workers have recently reported the preparation of a fluorodisaccharide in excellent yield without side products using XtalFluor-E, thus eliminating the need for purification. 9 The effective preparation of glycosyl fluorides from thio-, seleno-, telluro-and glycosyl sulfoxides has been performed in 30 minutes by Williams and co-workers with evidence that fluoride is delivered by the tetrafluoroborate counterion 10 (E) Enantioselective Ring Expansion of Prolinols: Direct ring expansion of N-alkyl prolinols to produce the corresponding 3-azidopiperidines in good and excellent regio-, diastereo-and enantioselectivity was achieved by using XtalFluor-E.…”

Solvent‐Free Conversion of Alcohols to Alkyl Iodides and One‐Pot Elaborations Thereof

“…This approach suffers from some drawbacks such as prolonged reaction times, need for high boiling solvents and, very often, large amounts of metal halides. A more direct approach is based on the combination of inorganic iodides with acidic promoters, such as KI/BF 3 Et 2 O, NaI/BF 3 Et 2 O, NaI/Amberlyst, CsI/BF 3 Et 2 O, KI/P 2 O 5 , ZrO 2 /SO 4 2− /NaI, XtalFluorE/TEAI/NaI, KSFclay supported/NaI . Iodination of hydroxyl groups via O‐alkyl isoureas represents another example of alternative strategies.…”

Amide Formation Using In Situ Activation of Carboxylic Acids with [Et2NSF2]BF4

“…Thus, an external fluoride source, such as Et 3 N · 3HF, is added for the reaction to proceed efficiently. Recently, our group10 and others11 have capitalized on this key difference by replacing the fluoride ions with other types of nucleophiles. We also reported the use of XtalFluor‐E as a dehydrating agent for the syntheses of various heterocycles 12.…”