Aza-nazarov reaction and the role of superelectrophiles

[GRAPHICS] The superacid-catalyzed reactions of N-acyliminium ion salts have been studied. The new conversions are remarkably similar to the Nazarov reaction and dicationic superelectrophilic species are thought to be involved. Experimental studies show that the cyclizations may be used to prepare varied heterocyclic products, while theoretical studies show that formation of the superelectrophiles can lead to very favorable reaction energetics.