Tetrahydrofuran (THF, 700 mL) was added to a 2000 mL round-bottomed flask under nitrogen protection, followed by addition of magnesium particles (11.8 g, 485 mmol) and 1,2-dibromoethane (2 drops) to the mixture and stirred at 45 °C. Maintaining the temperature at 45 °C, pre-prepared 4-bromo-N,N-bis(trimethylsilyl)aniline (70 g, 220 mmol) was slowly added to the reaction solution and stirred at reflux for 3 hours. Upon completion of the reaction, the reaction solution was cooled to 0 °C, followed by slow dropwise addition of tetramethyl orthosilicate (32.6 mL, 220 mmol, dissolved in 60 mL THF) solution at room temperature (25 °C). After the dropwise addition was completed, stirring was continued for 30 minutes at room temperature (25 °C). At the end of the reaction, an excess of saturated aqueous ammonium chloride (NH4Cl) solution was slowly added to the reaction mixture and stirred overnight. The reaction mixture was extracted with ethyl acetate (EA), the organic layer was separated, dried over anhydrous magnesium sulfate (MgSO4) and concentrated under reduced pressure. The resulting concentrate was purified by silica gel column chromatography (eluent ratio: ethyl acetate:hexane = 1:12) to give the final target product 4-(trimethoxysilyl)aniline (13.6 g, three-step overall yield 29%).
