39815-78-6

7732-18-5

107-08-4

105-45-3

39815-78-6

To a 200 mL solution of anhydrous tetrahydrofuran (THF) containing 14 mL of diisopropylamine was slowly added 59 mL of a 1.6 M butyllithium hexane solution under nitrogen protection and stirred for 20 minutes. Subsequently, 9.3 mL of methyl acetoacetate was added dropwise at 0°C and stirring was continued for 30 minutes. Another 54 mL of hexane solution of 1.6 M butyllithium was added slowly and stirred for 30 minutes before 8.4 mL of 1-iodopropane was added dropwise to the dark orange solution. The reaction mixture was gradually warmed to room temperature and stirring was continued for 30 minutes. A solution diluted by 50 mL of 37% hydrochloric acid and 100 mL of water was added slowly and dropwise while keeping the temperature below 15 °C. Upon completion of the reaction, the reaction mixture was extracted with ether (Et2O). The organic phase was washed with saturated sodium chloride (NaCl) solution, dried over anhydrous sodium sulfate (Na2SO4) and concentrated to dryness under reduced pressure. The residue was purified by column chromatography (eluent: ethyl acetate/hexane=1:9) to afford 8.3 g of the clear oily product methyl 3-oxoheptanoate in 61% yield.1H-NMR (200 MHz, CDCl3) δ: 0.90 (t, 3H), 1.22-1.65 (m, 4H), 2.53 (t, 2H), 3.44 (s, 2H), 3.73 (s, 3H).