Triisopropyl borate → 5-Allyl-2-hydroxy-3-methoxyphenylboronic acid

2-(4-Allyl-2-methoxyphenoxy)tetrahydropyran (2.0 g, 8.05 mmol) was dissolved in dry THF (70 ml) and the solution cooled to −78° C. sec-Butyl lithium (1.3M in hexanes, 7.4 ml, 9.62 mmol) was added dropwise with stirring over 10 minutes, the reaction was stirred at −78° C. for 2 hours. Triisopropoxy borane (3.4 ml, 14.6 mmol) was added and stirring continued for 4 hours at −78° C. The reaction was quenched with water, acidified to pH 1 with 2N hydrochloric acid and extracted with ether (2×200 ml). The combined extracts were dried with magnesium sulphate and concentrated under vacuum. The oily solid produced was triturated with cyclohexane and the solid filtered off to give the title compound (41%); MS 207 (M−H)−; HPLC retention time (system 1) 2.73 minutes.

1. additionwas added dropwise
2. stirringthe reaction was stirred at −78° C. for 2 hours
3. stirringstirring
4. waitcontinued for 4 hours at −78° C
5. customThe reaction was quenched with water
6. extractionextracted with ether (2×200 ml)
7. dry with materialThe combined extracts were dried with magnesium sulphate
8. concentrationconcentrated under vacuum
9. customThe oily solid produced
10. customwas triturated with cyclohexane
11. filtrationthe solid filtered off

ORD record

ord-a4856ba7822a4c26b6a5ce08bc558fe0

Source dataset

uspto-grants-2003_04

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US06541490B1