Iodine → 2-(Benzyloxy)-4-methoxyphenylboronic acid

Participants

Reaction Steps

To a stirred and gently refluxing suspension of magnesium powder (382 mg, 15.7 mmol) in THF (10 ml) containing a few crystals of iodine, was added dropwise, a solution of 2-benzyloxy-1-bromo-4-methoxybenzene (WO 93/08799, 4.39 g, 15.0 mmol) in THF (40 ml). After completion of the addition, the mixture was refluxed for 1.25 hours, cooled and then transferred via a canula to a stirred solution of trimethyl borate (3.11 g, 3.40 ml, 30.0 mmol) in THF (25 ml) at -78° C. The mixture was stirred at -78° C. for 30 minutes and then the cooling bath was removed and stirring was continued at room temperature for a further 2 hours. The mixture was partitioned between diethyl ether and 1 N HCl (200 ml) and the product was extracted into diethyl ether. The extracts were washed with water, dried (MgSO4) and concentrated to give a yellow solid. Trituration with warm diethyl ether/n-hexane gave after drying the title compound as a cream solid. Yield 2.159 g (56%).

Provenance & Evidence