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

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% yields. A preliminary biological screening of synthesized compounds is indicative of their potent anti‐cancer property.