Placed in a 2000-mL flask equipped with a stirrer, dropping funnel and thermometer were 54.3 mg (0.15 mmol) of Cu(OTf)2, 25 g of toluene and 93.1 mg (0.30 mmol) of triphenyl phosphate, and the inner atmosphere was replaced with nitrogen. After replacement with nitrogen, the mixture was stirred at 25° C. for 20 min. Then, 9 mL (18 mmol) of a toluene solution (2.0 mmol/L) of dimethylzinc was added to the mixture at 25° C., followed by further stirring for 10 min. The mixture was then cooled to −17° C., followed by addition of 1.68 g (16.5 mmol) of acetic anhydride, and 3.34 g (15 mmol) of 2-cyclopentadecenone was added dropwise to the mixture over the period of 1 hour. After completion of the dropwise addition, stirring was continued at the same temperature for 6 hours. After the reaction was completed, 32.5 g of a 5% aqueous sulfuric acid solution as cooled to 0° C. was added to the reaction mixture for quenching. After separation, the organic layer was washed with water (5 times), and the resultant organic layer was concentrated under reduced pressure to give 4.93 g of a crude product. The crude product was purified by silica-gel column chromatography to produce 3.89 g (13.8 mmol, 92% yield) of dl-3-methycyclopentadecene-1-yl acetate.
