Hydrochloric Acid → 4'Propyl-2-fluoro-4-biphenylboronic acid

Participants

Reaction Conditions

Reaction Steps

The product from step (ii) (10 g; 0.034 mol) in tetrahydrofuran (35 ml) was added dropwise to a suspension of magnesium turnings (0.88 g) in tetrahydrofuran (5 ml). The mixture was warmed to 75° C. when the Grignard reaction started. Further of the bromo compound was slowly added and the external heat source removed, a gentle reflux being maintained. After complete addition, the mixture was heated for 30 mins under reflux and then cooled to 15° C. A dry nitrogen atmosphere was introduced and trimethyl borate (3.77 g; 0.0363 mol) was slowly added and the mixture stirred at 15°-20° C. for 16 hrs. A 20% soln of hydrochloric acid (50 ml) was slowly added, the organic layer was separated, and the aqueous layer extracted with ether (2×50 ml). The combined organic layers were washed with brine and dried over sodium sulphate. Upon evaporation of the solvents a yellow solid was obtained. Yield 8.7 g; 100%.

Provenance & Evidence