22515-18-0

White to brown solid

4,4-Difluorocyclohexanone is used as a pharmaceutical intermediate.

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.

[1] Organic Letters, 2013, vol. 15, # 5, p. 1088 - 1091
[2] Tetrahedron, 2013, vol. 69, # 20, p. 4066 - 4075
[3] Patent: US2006/293392, 2006, A1. Location in patent: Page/Page column 51
[4] Patent: WO2008/7930, 2008, A1. Location in patent: Page/Page column 28
[5] Patent: WO2009/48547, 2009, A1. Location in patent: Page/Page column 40