| abstract |
The invention discloses a high-efficiency phase transfer catalyzed asymmetric fluorination method for 4-substituted pyrazolone compounds. The specific process is as follows: 4-substituted pyrazolone compounds, phase transfer catalyst and electrophilic fluorination reagent are mixed in a solvent Stir and mix evenly, then add alkali, and stir and react at ‑78~60 DEG C to prepare chiral α-fluoropyrazolones. This method uses a phase-transfer catalysis strategy to successfully realize a wide range, high-efficiency, and high enantioselectivity of asymmetric fluorination of 4-substituted pyrazolones using a cinchonadine-derived phase-transfer catalyst. The invention has mild reaction conditions, simple operation, good substrate applicability and environmental friendliness, low cost, and is suitable for large-scale industrial production. |