Ethanol (11.1 mL) was added to a solution of 2-bromocyclohex-1-enecarbaldehyde (2.22 g) in toluene (22.2 mL). 3-Nitrophenylboronic acid (2.34 g), tetrakis(triphenylphosphine)palladium (270 mg) and a 1 N sodium carbonate solution (14.0 mL) were added to the mixture. The atmosphere of the reaction system was replaced with nitrogen. Then, the reaction solution was stirred with heating under reflux for three hours. The reaction solution was cooled to room temperature, followed by extraction with ethyl acetate. The organic layer was dried over anhydrous magnesium sulfate. The drying agent was removed by filtration and the filtrate was concentrated under reduced pressure to obtain a residue. The residue was purified by silica gel column chromatography to obtain the title compound (2.00 g).
