4-Chloroaniline (76.5 mg, 0.6 mmol) and diphenylacetylene (71.3 mg, 0.4 mmol) were used as raw materials, and Cp*Rh(H2O)3(OTf)2 (11.8 mg, 5 mol%) was added to the reaction vials as a catalyst, acetic anhydride (59.0 μL, 0.6 mmol) as acylate, and 2.0 mL of tertiary amyl alcohol as the solvent. The reaction system was stirred at 100 °C for 24 h under oxygen atmosphere (1 atm). After completion of the reaction, NaOH (48 mg, 1.2 mmol) and methanol (2 mL) were added to the reaction mixture and stirring was continued for 2 hours. Subsequently, purification by column chromatography afforded the target compound 5-chloro-2,3-diphenyl-1H-indole (3ja) as a white solid in 90% yield.
