Potassium Permanganate → 7-Bromo-3,3-dimethyl-2,3-dihydrobenzofuran-5-carboxylic acid

Participants

Reaction Steps

A solution of 7-bromo-3,3-dimethyl-2,3-dihydro-benzofuran-5-carbaldehyde (14.61 g, 57.29 mmol) in acetone (80 mL) was added at room temperature to KMnO4 (9.05 g, 57.29 mmol) dissolved in water (200 mL). The reaction mixture was stirred at room temperature overnight filtered over celite then H2SO4 in water was added and the solution extracted with ethyl acetate. The organic layer was further washed with water and brine, dried over anhydrous magnesium sulfate, filtered and evaporated to give 9.9 g of 7-bromo-3,3-dimethyl-2,3-dihydro-benzofuran-5-carboxylic acid (64%). 1H NMR (300 MHz; CDCl3): 1.40 (s, 6H), 4.44 (s, 2H), 7.79 (s, 1H), 8.13 (s, 1H). c. 7-bromo-3,3-dimethyl-2,3-dihydro-benzofuran-5-carbaldehyde.

Provenance & Evidence