Water → (2,2-Dimethyl-4-oxo-chroman-6-yl)boronic acid

Participants

Reaction Steps

A solution of 6-bromo-2,2-dimethyl-2,3-dihydro-4H-chromen-4-one (21 g), pinacol diborane (25 g), palladium acetate (0.92 g) and potassium acetate (2.4 g) in N,N-dimethylformamide (250 mL) was stirred at 90° C. for 2 hr under an argon atmosphere. Water was added to the reaction mixture, and the mixture was extracted with diethyl ether. The organic layer was washed with saturated brine, and dried over anhydrous magnesium sulfate. The solvent was evaporated under reduced pressure. The residue was dissolved in tetrahydrofuran (80 mL), and 0.5 M hydrochloric acid (40 mL) and sodium periodate (7.0 g) were added at 0° C. The reaction mixture was stirred at room temperature for 2 hr and extracted with ethyl acetate. The organic layer was washed with saturated brine, and dried over anhydrous magnesium sulfate. The solvent was evaporated under reduced pressure. The residue was crystallized from ethyl acetate and hexane to give the title compound (15 g, 84%) as a colorless solid.

Provenance & Evidence