Photoinduced Ru‐Catalyzed Ortho ‐Alkylation of Aldimines With Primary Alkyl (Pseudo)Halides Under Ambient Conditions

The mild and efficient synthesis of alkyl‐substituted aromatic aldehydes remains challenging due to high‐temperature requirements, poor functional group tolerance, and the limited availability of alkylating reagents. Herein, we reported a cooperative photoredox/ruthenium catalytic system for the ortho ‐selective C–H alkylation of aldimines using primary alkyl (pseudo)halides under blue light irradiation at ambient temperature. This protocol accommodated a diverse range of 1‐naphthaldimines as well as previously unreactive benzaldimines, affording the corresponding alkylated products in moderate to high yields. Furthermore, the scope of alkylating reagents was significantly expanded to include alkyl iodides, bromides, chlorides, and alcohol‐derived tosylates or mesylates via in situ halogen exchange. Preliminary mechanistic studies suggested that the spiro[5.5] ruthenium complex supported by initial light‐induced ligand dissociation, may serve as the active species, enabling direct oxidative addition with alkyl halides. We believe that this protocol will provide a promising and mild platform for the rapid synthesis of natural products containing alkyl‐substituted aromatic aldehydes.