4,4-DIFLUOROCYCLOHEXANONE

176251-49-3

22515-18-0

4.3. Synthesis of 4,4-difluorocyclohexanone (8): the acetonide 7 (20.0 g, 112.2 mmol) was suspended in 20% HCl aqueous solution (16 mL) and stirred vigorously for 3 hours at 100 °C. After the reaction was completed, it was cooled to room temperature and NaCl (~3 g) was added to the aqueous phase to dissolve it. Subsequently, the aqueous phase was extracted with CH2Cl2 (3 x 50 mL). The organic phases were combined, washed with 50 mL of water, dried over Na2SO4, and the solvent was slowly evaporated under reduced pressure at 20 °C. Due to the extreme instability of the product, the material initially obtained was a 1:1 mixture of product 8 and raw material 5. After repeating the above operation, the ratio of 8 to 5 in the mixture was increased to 7:3. After a number of repetitions, the final product 8 was obtained with 95% purity as white crystals (11.0 g, 71% yield) with a melting point of 31-32°C. The product was then dried over 50 mL of water and evaporated slowly at 20°C under reduced pressure.