Interrupted Imino‐Nazarov Cyclization of 1‐Aminopentadienyl Cation and Related Cascade Process.

The Lewis acid catalyzed condensations of aldehyde (I) with secondary aniline derivatives involve the formation of an oxyallyl intermediate which undergoes intramolecular arene trapping to form tricyclic indoline-fused cyclopentanones (VI) and (VII).