One‐Pot Gold/Acid‐Catalyzed Synthesis of Indoloquinolin‐5(6H)‐ones from 1‐(2‐Ethynylphenyl)‐1H‐indoles

We present a method for the synthesis of substituted indolo[1,2‐a]quinoline‐5(6H)‐ones starting from 1‐(2‐ethynylphenyl)‐1H‐indoles. The transformation involves gold‐catalyzed oxidation of the triple bond followed by acid‐promoted intramolecular cyclization at the indole C2 position. Demonstrating noteworthy versatility, the reaction tolerates a wide array of substituents on the indole core and proceeds in good to excellent yields (up to 93 %).