Ethyl 4-iodobenzoate → Ethyl 4-(3,3-dimethylcyclobutanecarbonyl)benzoate

関与物質

反応条件

反応手順

In a 3-neck flask at −30° C. (monitored with thermalcouple) containing ethyl 4-iodobenzoate (25.0 g, 89.0 mmol) in anhydrous tetrahydrofuran (148 mL) was added isopropylmagnesium chloride (51.0 mL, 20.4 mmol) dropwise over 30 min. and then stirred at the same temperature for another 105 min. Copper iodide (5.07 g, 26.6 mmol) was then added quickly in one portion. The mixture was brought to −20° C. for 25 min. to ensure the solid has dissolved. The reaction is then brought back to −40° C. 3,3-dimethylcyclobutane carbonyl chloride (15.6 g, 106 mmol) was then added over 5 min. the reaction was then warmed to 0° C. over 4 h. The mixture was then diluted with 1 N HCl and extracted three times with ethyl acetate. The combined organic layers were then washed two times with brine and then dried over sodium sulfate, filtered, and concentrated to provide 26.6 g of crude brown oil. Purification by silica gel flash chromatography twice (0-5% ethyl acetate in heptane) afforded ethyl 4-(3,3-dimethylcyclobutanecarbonyl)benzoate (17.2 g, 74% yield) as an oil. 1H NMR (400 MHz, CDCl3) δ 8.11 (d, J=8.2 Hz, 2H), 7.93 (d, J=8.2 Hz, 2H), 4.40 (q, J=7.2 Hz, 2H), 3.89 (quin, J=8.8 Hz, 1H), 2.27-2.14 (m, 2H), 2.12-2.02 (m, 2H), 1.41 (t, J=7.1 Hz, 3H), 1.27 (s, 3H), 1.08 (s, 3H). MS (M+1): 261.2.

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