159191-56-7

67963-68-2

159191-56-7

Step 1b: Synthesis of 4-(tert-butyldimethylsilyloxy)phenylboronic acid (compound 0102) To a solution of anhydrous THF (20 ml) of compound 0101 ((4-bromophenoxy)tert-butyldimethylsilane, 1.548 g, 5.389 mmol) was slowly added dropwise 2.5 M hexane solution of n-butyllithium (2.5 ml, 6.326 mmol) at -78 °C under N2 protection for 15 min. The reaction mixture was continued to be stirred at -78 °C for 0.5 h. Then trimethyl borate (730 mg, 7.029 mmol) was slowly added dropwise for 15 min. After the dropwise addition, the reaction mixture was continued stirring at -78°C for 1 hour, followed by slow warming to room temperature. The pH of the reaction mixture was adjusted to 5-7 with aqueous hydrochloric acid to quench the reaction. The solvent was removed under reduced pressure and the residue was extracted with dichloromethane (DCM). The organic layer was washed with saturated saline, dried over anhydrous sodium sulfate and concentrated to give the crude product. The crude product was washed with petroleum ether (2 ml) to give the target product 0102 as a white solid (1.102 g, 81% yield): LCMS: 253 [M + 1]+.