Ionic liquids as new media for electrophilic trifluoromethylation reactions

The electrophilic trifluoromethylation of aniline with a range of trifluoromethyl sulfonium salts has been studied in ionic liquids as solvent. The best ionic liquid for this reaction was identified after extensive scrutiny of the influence of the cation's nature (imidazolium or pyridinium salts), the effect of the alkyl side chain length of the cation, as well as that of the counter anion. Recycling experiments have demonstrated that the purification protocol was greatly simplified over conventional reactions performed in DMF and that the solvent could be reused five times without significant loss of activity.

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► Design of the best ionic liquid and recycling experiments.
► Alternative solvent to the DMF usually used for electrophilic trifluoromethylation reactions.
► High yielding reaction enabling the isolation of the target compounds without purification.