Europium Triflate–Catalyzed One‐Pot Synthesis of 2,4,5‐Trisubstituted‐1H‐imidazoles via a Three‐component Condensation

A simple, efficient, and practical procedure for synthesis of 2,4,5‐trisubstituted‐1H‐imidazoles via the condensation of benzoin or acetoin, aromatic aldehydes, and ammonium acetate using europium triflate [Eu(OTf)3] as a novel catalyst in high yields is described. The catalyst can be recovered conveniently and reused at least four times without any loss of activity.