Intermolecular Dearomatization of Naphthalene Derivatives by Photoredox‐Catalyzed 1,2‐Hydroalkylation

An intermolecular hydroalkylative dearomatization of naphthalenes with commercially available α‐amino acids is achieved via visible‐light photoredox catalysis. With an organic photocatalyst, a series of multi‐substituted 1,2‐dihydronaphthalenes are obtained in good‐to‐excellent yields. Intriguingly, by tuning the substituents at the C2 position of naphthalenes, formal dearomative [3+2] cycloadditions occur exclusively via a hydroalkylative dearomatization–cyclization sequence. This overall redox‐neutral method features mild reaction conditions, good tolerance of functionalities, and operational simplicity. Diverse downstream elaborations of the products are demonstrated. Preliminary mechanistic studies suggest the involvement of a radical–radical coupling pathway. The development of dearomative functionalization strategies for arenes is intrinsically challenging and remains a largely unsolved synthetic problem owing to the particularly high resonance energy. We have now developed the first catalytic intermolecular hydroalkylative dearomatization of naphthalene derivatives with commercially available α‐amino acids by a photoredox‐neutral process.