The 10L glass reactor is equipped with mechanical stirring, thermometer and constant pressure dropping funnel. Under nitrogen protection, add 3 moles of raw material m-carboxybenzene boric acid and 4kg tetrahydrofuran. Add 4.5 moles of thionyl chloride dropwise under reflux and stirring, react for 4 hours, cool to 0-5°C, add 7.5 moles of potassium tert-butoxide in batches, continue stirring for 1 hour after the addition, add 2kg of water, and acidify with acetic acid. Let sit and let the liquid separate. The organic phase was concentrated to obtain a crude product, which was recrystallized by adding 2 kg of petroleum ether to obtain a solid product, 3-tert-Butoxycarbonylphenylboronic acid, with a purity of 98% and a molar yield of 95%.
