6999-03-7

68-12-2

2199-32-8

General procedure: 1-bromo-4-trimethylsilylbenzene (1.15 g, 5 mmol) was dissolved in tetrahydrofuran (THF, 30 mL) and the solution was cooled to -78 °C. Under argon protection, a hexane solution of 1.6 M n-butyllithium (3.13 mL, 5 mmol) was cooled to -78 °C and slowly added dropwise to the reaction solution, keeping the reaction temperature below -70 °C. After dropwise addition, the resulting clarified colorless solution was stirred at -78 °C for 15 min, followed by rapid addition of N,N-dimethylformamide (DMF, 1.156 mL, 15 mmol). The temperature of the reaction mixture was raised to -68 °C and stirring was continued at -78 °C for 15 min. Upon completion of the reaction, the reaction was quenched with 1 N aqueous hydrochloric acid and extracted twice with ether. The organic layers were combined and washed sequentially with water twice, saturated aqueous sodium chloride once, and then dried with anhydrous sodium sulfate. After filtration, the solvent was removed by evaporation to give 4-trimethylsilylbenzaldehyde as a colorless oil (920 mg, 100% yield). The product was sufficiently pure to be used directly in the subsequent reaction. Mass spectrum (ISP) m/z: 179.2 ([M + H]+). 1H NMR (CDCl3, 300 MHz) δ: 10.02 (s, 1H), 7.84 (d, J = 8.1 Hz, 2H), 7.69 (d, J = 8.1 Hz, 2H), 0.31 (s, 9H).