Photoredox Radical Cascade Cyclization of 2‐Alkynylarylnitriles in Visible Light: Direct Access to 3‐Amino‐1‐indenones

Abstract A photoinduced direct synthesis of 3‐amino‐1‐indenones via radical cascade cyclization strategy is demonstrated. The methodology involves a domino reaction between 2‐alkynylarylnitrile and N ‐aminopyridinium salt and captures the reactivity of in‐situ generated nitrogen‐centered radical (NCR) in visible light. Multiple bond‐forming events including C−N, C−C, and C−O take place sequentially on 2‐alkynylarylnitrile enabling construction of 3‐amino‐1‐indenone core at room temperature in 35–76% yield. A preliminary biological screening of synthesized compounds is indicative of their potent anti‐cancer property.