Base‐Assisted Orthogonal Synthesis of 4‐Arylisoquinolinediones and Azanaphthoquinones from 2‐Alkynylarylnitriles via Photoactivation by Pyrylium Salt in Visible Light

A metal‐free, photooxidative activation of 2‐alkynylarylnitriles in presence of pyrylium salt as a photocatalyst is reported. The 1,2‐diketone intermediate generated in visible light demonstrates base‐assisted orthogonality toward cyclization, furnishing 4‐aryl‐4‐hydroxyisoquinoline‐1,3‐(2 H ,4 H )‐dione and 3‐aryl‐3‐hydroxy‐2,3‐dihydroazanaphthoquinone derivatives. The reaction has a wide substrate scope, good functional group tolerance, uses an organic photocatalyst, and takes place at room temperature. Preliminary biological screening of synthesized molecules reveals their potential as anticancer agents.