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

Temperature

-78 °C

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.

1. stirringThe reaction was stirred at −78° C. for 1 hour
2. temperatureto warm to room temperature overnight
3. customThe reaction was quenched with water
4. extractionextracted with DCM (2×200 ml)
5. washThe combined organic extracts were washed with 2N hydrochloric acid (50 ml)
6. dry with materialdried with magnesium sulphate
7. concentrationconcentrated under vacuum
8. customThe oily solid produced
9. customwas triturated with cyclohexane

ORD record

ord-88f70b7dc4cd4c319d6d7e9d8b0b0c5d

Source dataset

uspto-grants-2003_04

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US06541490B1