Sulfuric Acid → (2H-1,3-benzodioxol-5-yl)boronic acid

Participants

Reaction Steps

Butyl lithium (BuLi) (5.6 mL, 1.40 equiv) was added dropwise to a solution of 5-bromobenzo[d][1,3]dioxole (2 g, 9.95 mmol, 1.00 equiv) and triisopropyl borate (1.96 g, 14.00 mmol, 1.40 equiv) in THF (20 mL) at −78° C. in a 100-mL 3-necked round-bottom flask under an inert atmosphere of nitrogen. The mixture was stirred at room temperature for 4 hr, quenched with water (10 mL), and acidified with H2SO4 (4.9 g, 50.00 mmol, 5.00 equiv). The resulting solution was allowed to react, with stirring, overnight while the temperature was maintained at reflux. The solution was extracted with 3×50 mL of ethyl acetate and the organic layers combined, dried over anhydrous sodium sulfate and concentrated under vacuum. The resulting solid material was washed with 3×3 mL of ethyl acetate. This resulted in 0.5 g (30%) of benzo[d][1,3]dioxol-5-ylboronic acid as a white solid.

Provenance & Evidence