Modular Assembly of Acridines by Integrating Photo‐Excitation of o‐Alkyl Nitroarenes with Copper‐Promoted Cascade Annulation

Acridine frameworks stand as pivotal architectural elements in pharmaceuticals and photocatalytic applications, owing to their chemical adaptability, biological activity, and unique excited‐state dynamics. Conventional synthetic routes often entail specialized starting materials, anaerobic or moisture‐free conditions, and elaborate multi‐stage manipulations for incorporating diverse functionalities. Herein, we present a convergent approach integrating photo‐excitation of readily available ortho‐alkyl nitroarenes with copper‐promoted cascade annulation. This innovative system enables an aerobic, one‐pot reaction of o‐alkyl nitroarenes with arylboronic acids, thereby streamlining the modular construction of a wide array of acridine derivatives with various functional groups. This encompasses symmetrical, unsymmetrical and polysubstituted varieties, some of which are otherwise exceptionally difficult to synthesize. Furthermore, it significantly improves the production of structurally varied acridinium salts, featuring enhanced photophysical properties, high excited state potentials (E*red=2.08–3.15 V), and exhibiting superior performance in intricate photoredox transformations. We hereby introduce a potent and modular synthetic strategy for the assembly of valuable acridine architectures, leveraging the synergistic combination of photo‐excitation of o‐alkyl nitroarenes with copper‐mediated cascade annulation. This approach facilitates the rapid construction of a diverse collection of symmetric, unsymmetric, and poly‐substituted acridines, which can be seamlessly converted into precious acridinium photocatalysts. Notably, certain members of this class exhibit extraordinary oxidative strength, thereby unlocking immense potential for advancing the realm of photochemical reactions.