Method 1,
0.2 mL of cuprous oxide/NH3 catalytic system, 135.8 mg of o-methylphenylboronic acid, 0.830 g of potassium iodide, and 2 mL of water were added to a round-bottom flask equipped with a magnetic stirrer. The system was left open at room temperature for 24 hours. After the reaction was complete, 1.5 mL of 2 mol/L sodium hydroxide solution was added, and the mixture was extracted three times with 2 mL of dichloromethane each time. The combined organic phases were concentrated to give 176 mg of 2-iodotoluene, with a yield of 81%. Method 2,
Accurately weigh o-bromotoluene (42.8 mg, 0.25 mmol), tetramethylammonium iodide (150.79 mg, 0.75 mmol), cuprous oxide (3.6 mg, 0.025 mmol), and L-proline (5.8 mg, 0.05 mmol), and add them sequentially to a 25 mL Schlenk flask. Add purified ethanol (1.5 mL) and react in a 110 °C oil bath for 30 h. After the reaction is complete, filter the reaction solution through a silica gel column into a 10 mL volumetric flask, and quantify the solution volume to the specified mark with ethyl acetate. Gas chromatography analysis showed that the yield of 2-iodotoluene was 28%.
