Hydrochloric Acid → Dibenzo(b,d)furan-2-ylboronic Acid (contains varying amounts of Anhydride)

Participants

Reaction Conditions

Reaction Steps

Under an argon atmosphere, 400 mL of anhydrous tetrahydrofuran (THF) were added to 24.7 g (100 mmol) of 2-bromodibenzofuran, and the mixture was stirred at −40° C. During the stirring, 63 mL (100 mmol) of a 1.6-M solution of n-butyllithium in hexane were added to the mixture. The reaction solution was stirred for 1 hour while being heated to 0° C. The reaction solution was cooled to −78° C. again, and a solution of 26.0 g (250 mmol) of trimethyl borate in 50 mL of dry THF was dropped to the solution. The reaction solution was stirred at room temperature for 5 hours. 200 mL of 1N hydrochloric acid were added to the reaction solution, and the mixture was stirred for 1 hour. After that, the water layer was removed. The organic layer was dried with magnesium sulfate, and the solvent was removed by distillation under reduced pressure. The resultant solid was washed with toluene, whereby 15.2 g of dibenzofuran-2-boronic acid were obtained (72% yield).

Provenance & Evidence