Metal free, I2-catalyzed [3+1+1] cycloaddition reactions to synthesize 1,2,4-trisubstituted imidazoles

We have successfully developed an operationally simple and economical one-pot three-component cycloaddition reaction to synthesize 1,2,4-trisubstituted imidazoles by employing aldehydes, α-amino carbonyl compounds and ammonium acetate. The transformation is environmentally friendly and metal free by employing I2 (10 mol %) as a catalyst and EtOH as a solvent, and a wide range of function groups and heterocyclics are well tolerated resulting in moderate to good yields.32