Ionic Liquid-Assisted Grinding: An Electrophilic Fluorination Benchmark

We demonstrated the influence of liquid additives on the rate and selectivity of mechanochemical fluorination of aromatic and 1,3-dicarbonyl compounds with F-TEDA-BF4. Substoichiometric catalytic quantities of ionic liquids speed up the reaction. We proposed an improved protocol for ionic liquids-assisted fluorination that allows easy and efficient isolation of fluorinated products by vacuum sublimation. A careful choice of additive results in high yields of fluorinated products and low E-factor for the overall process. Here, we report a benchmarking study of various ionic liquids in comparison with representative molecular solvents. A lower viscosity of ionic liquid additive is typically associated with higher yields and a higher degree of difluorination. Ionic liquids with fluorous anions (triflate and triflimide) are shown to be the most efficient catalysts for ionic liquid-assisted grinding.

Automated summary

The influence of liquid additives on the rate and selectivity of mechanochemical fluorination has been demonstrated, with ionic liquids shown to catalyze the reaction and improve the isolation of fluorinated products. A careful choice of additive results in high yields of fluorinated products and low E-factor for the overall process.