A. Synthesis of 1-(4-bromophenyl)-2,2,2-trifluoro-1-acetophenone
1,2-Dibromobenzene (6.0 g, 0.025 mol) was dissolved in 59 mL of anhydrous tetrahydrofuran in a flame-dried flask. The solution was cooled to -78 °C in a dry ice/acetone bath and n-butyllithium (2.56 M hexane solution, 9.8 mL, 0.025 mol) was slowly added dropwise, keeping the reaction temperature below -60 °C during the reaction. After addition, the reaction mixture was stirred at -78 °C for 1 hour. The solution was then added dropwise via cannula to a solution of ethyl trifluoroacetate (3.56 g, 0.0257 mol) in 36 mL of ether and cooled to -78 °C. After addition, the reaction mixture was stirred at -70 °C for 15 min and then gradually warmed to room temperature. The reaction mixture was partitioned between ether and saturated aqueous ammonium chloride solution, and the pH of the aqueous phase was adjusted to about pH = 2 by dropwise addition of 1 M HCl. The organic phase was washed with brine, dried over MgSO4, filtered, and concentrated to give 10 g (> 100%) of crude compound A, which was used without further purification for the next reaction.
