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

Trifluoromethane (HCF₃, HFC-23) 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.