Photoactivated Formal [3 + 2] / [4+2] Cycloaddition of N‐Aryl Cyclopropyl and Cyclobutylamines

Abstract Organic transformations initiated by photochemical activation have been at the forefront of reaction discovery. In this study, we present a formal photochemical [3+2] and [4+2] cycloaddition using N ‐aryl cyclopropylamines and N ‐aryl cyclobutylamines in conjunction with α , β ‐unsaturated carbonyl systems, unveiling two distinct mechanistic pathways. The [3+2] cycloaddition is elucidated as being guided by the photochemical activity of an electron donor‐acceptor (EDA) complex. Simultaneously, intermolecular [4+2] annulation of cyclobutylanilines is achieved by visible‐light photoredox catalysis. These simple methodologies have wide applicability, facilitating the synthesis of N ‐arylaminocycloalkyl compounds in yields ranging from good to excellent.