Synthesis
1. Oxidation: 4-(Trifluoromethyl)benzaldehyde (1.54 g, 6.75 mmol, 1.0 eq.) and dichloromethane (20 mL) were added to a round-bottomed flask and m-chloroperoxybenzoic acid (mCPBA, 1.52 g, 6.78 mmol, 1.0 eq.) was added slowly at room temperature. The reaction mixture was stirred at room temperature for 2 hours. Upon completion of the reaction, the reaction was quenched by the addition of saturated aqueous sodium bisulfite solution (15 mL). The mixture was transferred to a partition funnel and extracted with dichloromethane. The organic phases were combined, dried with anhydrous sodium sulfate and concentrated under reduced pressure to give 4-(trifluoromethyl)phenol in 71% yield.
2. Chlorination reaction: N-chlorosuccinimide (NCS, 25.0 mmol, 3.4 g) and dichloromethane (20.0 mL) were added to another round-bottomed flask and cooled to -78 °C. The reaction was carried out by adding zirconium tetrachloride (ZrCl2) to the mixture. Zirconium tetrachloride (ZrCl4, 0.5 mmol, 300 mg) was added, followed by 4-(trifluoromethyl)phenol (25.0 mmol). The reaction mixture was warmed to room temperature and stirred for 6 hours. After completion of the reaction, it was extracted with saturated aqueous sodium bicarbonate. The organic phases were combined and the solvent was removed under reduced pressure to afford 2-chloro-4-(trifluoromethyl)phenol in 88% yield.
References
[1] Patent: US4607128, 1986, A
[2] Journal of the American Chemical Society, 2009, vol. 131, p. 4031 - 4041
[3] Patent: CN107915584, 2018, A. Location in patent: Paragraph 0025; 0026; 0027; 0028
[4] Patent: CN108276254, 2018, A. Location in patent: Paragraph 0012; 0013; 0014; 0015
[5] Patent: US4076741, 1978, A
