Trimethyl borate → (2-Methoxy-4-methylphenyl)boronic acid

Participants

Reaction Conditions

Reaction Steps

To a cooled (−78° C.) solution of 1-bromo-2-methoxy-4-methylbenzene (0.5 g; 2.49 mmol) in dry THF (12.5 mL) under argon atmosphere was added dropwise a tert-butyllithium solution (1.6M in pentane) (3.65 mL; 5.47 mmol). After 10 min, trimethyl borate (0.424 mL; 3.73 mmol) was added dropwise as a neat liquid and the reaction was stirred at −78° C. for 1 h. The reaction was allowed to warm up to room temperature and was stirred for another 1 h. The mixture was quenched with a saturated solution of ammonium chloride and the mixture was concentrated under reduced pressure. The residue was acidified with a solution of hydrochloric acid 2N and the mixture was extracted with dichloromethane. The organic layer was washed with brine, dried over magnesium sulphate and concentrated under reduced pressure. The crude product was precipitated out off a mixture of dichloromethane-heptane, filtered, washed with heptane and dried under reduced pressure to afford 0.095 g (23%) of the title compound as an off-white solid.

Provenance & Evidence