Synthesis of 5-(trifluoroacetyl)imidazoles from Bromoenones and Benzimidamides via Aza-Michael Initiated Ring Closure Reaction

Introduction: A simple method for the preparation of 5-(trifluoroacetyl)imidazoles was elaborated. Methods: The reaction of trifluoromethyl(α-bromoalkenyl)ketones with benzimidamides was employed to afford the target heterocycles in good yields. Results: The assembly of imidazole core proceeds viaaza-Michael adduct formation followed by intramolecular nucleophilic substitution and spontaneous aromatization as an oxidation sequence. Conclusion: The yields of target imidazoles can be improved by the use of soft oxidizing agents.