A mixture of tert-butyl 9-bromo-2,3-dihydro-1,4-benzoxazepine-4(5H)-carboxylate (1.00 g, 3.05 mmol), isopropenyl boronic acid pinacol ester (513 mg, 3.05 mmol), saturated aqueous sodium carbonate solution (14 ml) and tetrakis(triphenylphosphine)palladium(0) (99.5 mg, 0.0861 mmol) in dimethoxyethane (17 ml) was stirred at 85° C. for 12 hr under a nitrogen atmosphere. The reaction mixture was poured into water, and the mixture was extracted with ethyl acetate. The extract was washed with water, and dried over anhydrous magnesium sulfate. The solvent was evaporated under reduced pressure, and the residue was purified by silica gel column chromatography (hexane:ethyl acetate=3:1) to give the desired product (680 mg, 77.0%) as an oil.
