0.005 mmol of transition metal catalyst was accurately weighed and added to a 10 mL Young reaction tube equipped with a magnetic stirrer. Under oxygen atmosphere, 0.04 mmol of co-catalyst I, 0.08 mmol of co-catalyst II, 0.2 mmol of 4-formylaniline and 1 mL of anhydrous ethanol were added sequentially to the reaction tube. The Young reaction tube was placed on a magnetic stirrer and the reaction was stirred at 150 °C for 30 hours. After completion of the reaction, the pH of the reaction mixture was adjusted to neutral, and 2-methyl-6-formylquinoline was obtained in pure form in 75% yield after post-processing.
