Trimethyl borate → 5-(But-3-enyloxy)-2,4-dimethylphenylboronic acid

Participants

Reaction Conditions

Reaction Steps

In the glovebox, a 100-mL round bottomed flask is charged with 1-bromo-5-(but-3-enyloxy)-2,4-dimethylbenzene (3.142 g, 13.6 mmol) and THF (100 mL). The flask is sealed with a septum and removed from the glovebox. The flask is cooled to −70° C. under nitrogen purge. BuLi (1.6M in hexanes, 8.2 mL, 13 mmol) is added slowly, keeping the temperature below −68° C., and the reaction mixture is stirred for one hr at −70° C. Trimethylborate (1.3 mL, 12 mmol) is added, and the mixture is stirred as it slowly warms to room temperature. Solvents are removed on a rotovap, and ice (60 g) containing hydrochloric acid (HCl) (conc, 5 mL) is added, and then ether (60 mL). A white precipitate forms, and this is collected on a fine frit. Yield=1.283 g of a white solid. 1H NMR is taken by suspending the solid in d6-dimethylsulfoxide (d6-DMSO) and adding a trace of HCl.

Provenance & Evidence