A direct method for the synthesis of 1,2,5-triaryl-1H-imidazoles was achieved easily from cyclization of aryl acetaldehydes with amidines catalyzed by I2. Various substitued groups can be employed, and this reaction proceeds smoothly in moderate to good yields.
A novel process using N-benzylhydroxylamine hydrochloride as a “C1N1 synthon” in [2+2+1] cyclization for the construction of 1,2,5-trisubstituted imidazoles has been described for the first time. The key to realizing this process lies in capturing arylamines by in situ generated novel acyl ketonitrone intermediates. Subsequent tautomerization activates the α-C(sp3)–H of N-benzylhydroxylamines, and