Synthesis of 1,2,4-Oxadiazoles by Tandem Reaction of Nitroalkenes with Arenes and Nitriles in the Superacid TfOH.

The tandem reaction of nitroalkenes with arenes and nitriles in the superacid CF3SO3H (TfOH) results in the formation of 1,2,4-oxadiazole derivatives in yields up to 96%. This reaction proceeds via the consequent interaction of arenes and nitriles, as nucleophiles, with intermediate cationic species derived by the protonation of nitroalkenes in TfOH. This is novel and general synthesis of 1,2,4-oxadiazoles, which are very important compounds for medicinal chemistry.