Triisopropyl borate → (2-Hydroxy-5-methoxyphenyl)boronic acid

Participants

Reaction Conditions

Reaction Steps

2-(2-Bromo-4-methoxyphenoxy)tetrahydropyran (1.9g, 6.62 mmol) was dissolved in dry THF (25 ml) and the solution cooled to -78° C. under nitrogen. n-Butyl lithium (1.6M in hexanes, 4.6 ml, 7.36 mmol) was added dropwise with stirring over 10 minutes. The reaction was stirred at −78° C. for 1 hour. Triisopropoxy borane (1.6 ml, 6.9 mmol) was added dropwise and the mixture allowed to warm to room temperature overnight. The reaction was quenched with water, acidified to pH 1 with 2N hydrochloric acid and extracted with DCM (2×200 ml). The combined organic extracts were washed with 2N hydrochloric acid (50 ml), dried with magnesium sulphate and concentrated under vacuum. The oily solid produced was triturated with cyclohexane to give the title compound as a pale brown solid (660 mg, 59%); MS 166/167 (M−H)−; HPLC retention time (system 2) 3.53 minutes.

Provenance & Evidence