Synthesis
To a suspension containing aluminum trichloride (34.59 g, 259 mmol) and 1,4-difluorobenzene (20 g, 18.18 mL, 175.3 mmol), chloroacetyl chloride (21.778 g, 192.83 mmol) was slowly added dropwise at 0 °C, and the dropwise addition process was controlled to be completed within 20 minutes. The reaction mixture was stirred at 0 °C for 1 h and then warmed up to 60 °C to continue the reaction for 1 h until a clarified solution was formed. Subsequently, the reaction solution was carefully poured into about 400 mL of ice-cold 1 M hydrochloric acid. At this point, a colorless solid precipitated. The aqueous phase was extracted with ether (3 x 50 mL) and the combined organic phases were washed with saturated sodium bicarbonate solution (40 mL) and dried over anhydrous magnesium sulfate. Finally, the organic phase was concentrated by rotary evaporator to give 27.93 g (84% yield) of the colorless crystalline product 2-chloro-2',5'-difluoroacetophenone.
References
[1] Patent: WO2015/139859, 2015, A1. Location in patent: Paragraph 0079
[2] Organic Letters, 2007, vol. 9, # 4, p. 667 - 669
[3] Pharmazie, 1976, vol. 31, # 6, p. 351 - 354
[4] Tetrahedron Asymmetry, 2007, vol. 18, # 8, p. 949 - 962
