Trityl chloride (TrCl or Ph3CCl) efficiently catalyzes the one-pot multi-component condensation of benzil with aldehydes, primary amines and ammonium acetate under neutral and solvent-free conditions to give 1,2,4,5-tetrasubstituted imidazoles in high to excellent yields and in short reaction times. Mechanistically, it is attractive that trityl chloride promotes the reaction by in situ generation of trityl carbocation (Ph3C+).
