Method for preparing arylboronic acid compound

The invention provides a method for preparing an arylboronic acid compound shown in the formula (I). The method includes the following steps that (1) a Grignard reagent is prepared, wherein in an anhydrous organic solvent, a magnesium rod and one to two drops of iodine are added, a substance shown in a formula (II) and acquired by dissolving the anhydrous organic solvent at certain concentration is dripped, a Grignard reaction is conducted, and the Grignard reagent is generated; (2) a compound shown in the formula (I) is prepared, wherein the Grignard reagent is dripped into an organic solution shown in a formula (III) and acquired by dissolving the anhydrous organic solvent at certain concentration, a synthetic reaction is conducted, and after the reaction is finished, the compound shown in the formula (I) is acquired after hydrolysis and aftertreatment, wherein the formula (I), the formula (II) and the formula (III) are shown in the specification, and R1, B, O and R2 are defined in the specification.