Triethylamine → Hex-5-EN-1-YL 2-bromo-2-methylpropanoate

5-Hexen-1-ol (42.6 g), triethylamine (45.8 g), and tetrahydrofuran (0.8 L) were mixed. After ice cooling, 2-bromoisobutyryl bromide (100 g) was dropped. The reaction liquid was stirred at 4° C. for 3 hours, and then at room temperature for 15 hours. The reaction liquid was then filtered, concentrated with an evaporator, and dissolved in diethyl ether (300 mL). The solution was washed with a 1N hydrochloric acid solution (2×300 mL), a saturated sodium bicarbonate solution (2×300 mL), and distilled water (2×300 mL), in this order. After that, the organic layer was dried over sodium sulfate, filtered, and concentrated with an evaporator. The product was then purified through a silica gel column (developing solvent: hexane/ethyl acetate=15/1), and concentrated to give 74.2 g of 5-hexenyl 2-bromo-2-methylpropanate of the following chemical formula (compound 1).