Continuous-Flow Synthesis of Perfluoroalkyl Ketones via Perfluoroalkylation of Esters Using HFC-23 and HFC-125 under a KHMDS–Triglyme System
Yamato Fujihira, Hiroto Iwasaki, Yuji Sumii, Hiroaki Adachi, Takumi Kagawa, Norio Shibata
Abstract
Abstract Hydrofluorocarbons (HFCs) are widely used as cooling agents in refrigerators and air conditioners and as solvents in industrial processes. However, their application has been restricted by their high global warming potential. Thus, strategies for HFC decomposition and effective utilization are urgently required. Herein, we describe a method for the chemical transformation of two HFCs, viz. HFC-23 and HFC-125, based on the continuous-flow perfluoroalkylation of esters to synthesize the pharmaceutically and agrochemically vital trifluoromethyl and pentafluoroethyl ketones. The combination of a potassium base and a glyme solvent system is found to be the most effective. The proposed method is attractive for industrial use because it allows the consumption of a large volume of HFCs, promotes the synthesis of high-value medicinal compounds, and serves as an ideal alternative to the current HFC decomposition processes like thermal plasma treatment.