[Synthesis]
1-(2,3-Dihydrobenzofuran-6-yl)ethanone was synthesized using 6-bromo-2,3-dihydrobenzofuran (1 g, 5.03 mmol) as starting material according to the literature and methods known to those skilled in the art. The procedure was as follows: 6-bromo-2,3-dihydrobenzofuran (1 g, 5.03 mmol) was dissolved in toluene (10 mL) under nitrogen protection and degassed for 30 min. Subsequently, 1-ethoxyvinyltributyltin (2.012 g, 5.53 mmol) and bis(triphenylphosphine)palladium dichloride (0.35 g, 0.50 mmol) were added sequentially at room temperature, and the reaction mixture was heated to 90 °C and stirred for 16 hours. After completion of the reaction, it was cooled to room temperature and filtered through diatomaceous earth. The filtrate was concentrated under reduced pressure and 6N aqueous hydrochloric acid (10 mL) was added and stirred at room temperature for 1 hour. The reaction solution was concentrated again and neutralized with saturated sodium bicarbonate solution. The product was extracted with dichloromethane (50 mL) and the organic phase was dried with anhydrous sodium sulfate, filtered and concentrated. The crude product was purified by fast column chromatography to afford the target compound 1-(2,3-dihydrobenzofuran-6-yl)ethanone in 73.7% yield (0.6 g, light yellow solid). The product was confirmed by 1H NMR (400 MHz, DMSO-d6) and LCMS (Method A) with the following results: 1H NMR (400 MHz, DMSO-d6): δ 7.48 (d, J = 7.64 Hz, 1H), 7.37-7.35 (d, J = 7.68 Hz, 1H), 7.26 (s, 1H), 4.58 (t, J = 8.76 Hz, 2H), 3.24 (t, J = 8.76 Hz, 2H), 2.53 (s, 3H). LCMS: (Method A) 163.2 (M + H), Rt. 3.01 min, 97.60% (Max). |