Hydrochloric Acid → 5-Chloro-2-methoxyphenylboronic acid

Participants

Reaction Steps

A solution of 2-bromo-4-chloroanisole (5.0 g, 22.6 mmol) in dry THF (60 ml) under nitrogen was cooled to −70° C. and n-butyl lithium (12.4 ml of a 2.0 M solution in hexanes, 24.8 mmol) was added. After 10 min. at −70° C. tributyl borate (8.5 ml, 31.4 mmol) was added and the temperature was allowed to rise to room temperature overnight. Aqueous hydrochloric acid (40 ml, 2 M) was added and the product was extracted with 2×60 ml ether. The ethereal phase was extracted with aqueous sodium hydroxide (2×40 ml, 1 M). Acidification with concentrated HCl during ice-cooling gave a precipitate that was dissolved in ether. Drying over magnesium sulfate and evaporation of the solvent gave the title compound. Yield 1.93 g, 46%.

Provenance & Evidence