Under nitrogen protection, an anhydrous tetrahydrofuran (THF) solution of pinacol isopropyl borate was slowly added dropwise to a THF solution of cyclopropyl magnesium bromide over a period of more than 30 minutes. After the addition was complete, the mixture was stirred at room temperature for 5 hours, then naturally heated to 25°C and stirred for another 16-20 hours. The reaction progress was monitored by TLC. After the reaction was complete, the reaction solution was poured into a 1:1 mixture of saturated ammonium chloride aqueous solution and ethyl acetate, stirred, and separated. The organic phase was washed with saturated brine, dried, and concentrated. Finally, the product was purified by column chromatography to obtain pinacol isopropyl borate. Throughout the reaction, strict control of the solvent drying degree and the inert atmosphere of the operating environment is necessary to ensure the smooth progress of the reaction and the acquisition of a high-purity product.
