1. In a dry reaction flask, 3-bromophenol (1.28 g, 7.39 mmol) was dissolved in DMF (12.0 mL).
2. Sodium 2-chloro-2,2-difluoroacetate (2.82 g, 18.49 mmol) and Cs2CO3 (4.82 g, 14.79 mmol) were added sequentially.
3. the reaction mixture was heated to 100 °C. Note that gas is released during the reaction and caution should be exercised.
4. After 2 hours of reaction, cool to room temperature and dilute the reaction mixture with EtOAc. 5.
5. Wash the organic layer with water and brine, and then extract the aqueous phase with EtOAc three times. 6.
6. All organic layers were combined, dried with anhydrous magnesium sulfate, filtered and concentrated.
7. The crude product was purified by silica gel column chromatography (eluent: 0-5% EtOAc in hexane solution) to afford the target compound T18.1 as an oil in 61% yield. The product could be used in the next reaction without further purification.
