Synthesis
The general procedure for the synthesis of 2,6-dichlorobenzaldehyde from 2,6-dichlorobenzaldehyde was as follows: first, 34.8 g (0.6 mol) of potassium fluoride (KF) was dissolved in 250 mL of cyclobutanesulfone under nitrogen protection and stirred at 100 °C for 2 h. The water was removed by azeotropic distillation. Subsequently, 20 g (0.11 mol) of 2,6-dichlorobenzaldehyde and 2.8 g (6.68 mmol) of tetraphenylphosphonium bromide were added to this anhydrous mixture and the reaction mixture was heated to 180 °C and kept overnight. Upon completion of the reaction, the solid product was washed with ethyl acetate and the solvent was removed by aqueous pressure evaporation. Finally, the target product 2,6-difluorobenzaldehyde was purified by vacuum evaporation (24 mbar, 85-86 °C) in 77% yield.
References
[1] Patent: WO2016/102207, 2016, A1. Location in patent: Page/Page column 32
[2] Journal of Fluorine Chemistry, 2004, vol. 125, # 6, p. 1031 - 1038
[3] Chemistry Letters, 1988, # 9, p. 1355 - 1358
[4] Angewandte Chemie - International Edition, 2006, vol. 45, # 17, p. 2720 - 2725
[5] Patent: US6103659, 2000, A