A Photochemical One-Pot Three-Component Synthesis of Tetrasubstituted Imidazoles

Tetrasubstituted imidazoles can be formed in a photochemical one-pot synthesis from aldehydes, α-aminonitriles, and isoxazoles. Condensation of the first two components produces α-(alkylideneamino)­nitriles which react under basic conditions with the acylazirines formed in situ by photochemical ring transformation of the isoxazole component. This process includes an unusual cleavage of the C²–C³ bond of the acylazirine. The reaction mechanism was studied by DFT calculations