Palladium-Catalyzed One-Pot Synthesis of 3-Arylindoles Based on <i>o</i> -Iodoaniline with Aryl Hydrazones

A tandem one-pot strategy for the efficient synthesis of indole derivatives has been developed via palladium-catalyzed coupling of <i>ortho</i>-iodoanilines with <i>N</i>-tosylhydrazones under basic conditions. The reaction proceeds through in situ formation of <i>o</i>-vinylaniline intermediates, followed by oxidative cyclization under palladium catalysis. The substrate scope study provided substituted 3-phenylindoles in moderate to good yields, demonstrating the method's practicality for indole construction. Notably, no protection of the indole N-H is required, representing a key advantage.