Defluoroalkylation of Trifluoromethane with Organolithium Reagents: Mechanism and Synthesis of Fluoroalkenes

Trifluoromethane (HCF3) is a byproduct of fluoropolymer production that has limited applications. It is often stored or destroyed at the point of production, but if released into the environment is a potent greenhouse gas with a global warming potential of 14,600 times that of CO2. State-of-the-art chemical technologies for upgrading HCF3 typically occur with conservation of the CF3 group. These approaches will come under increased scrutiny as concern over the environmental impact of perfluoroalkyl substances (PFAS) continues to grow. A more sustainable approach involves synthetic transformations that repurpose the atomic content of HCF3 while also destroying the CF3 group. In this paper, we report a rare example of the transformation of HCF3 into a fluoroalkene functional group through defluoroalkylation. We rationalise product formation through DFT calculations, scale-up the synthesis through continuous flow methods, and show that a fluoroalkene reagent derived from HCF3 is a competent nucleophile for the fluoroethenylation of a range of aldehydes.