Fluoropolymer manufacturing produces a large volume of fluoroform (HCF₃) as a byproduct. Fluoroform is a potent greenhouse gas. Using HCF₃ as a trifluoromethylating reagent is preferable to its destruction. However, known applications of HCF₃ are limited to nucleophilic and copper-promoted trifluoromethylation reactions. Converting HCF₃ to metal–CF₃ complexes could broaden the synthetic applications.

Feng-Ling Qing, Donghua University, Shanghai, China, and Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences, and colleagues have developed a method for the transformation of HCF₃ into synthetically useful AgCF₃. Treatment of HCF₃ with tBuOK and AgOAc in N,N-dimethylformamide (DMF) produces a stable AgCF₃ solution. Until now, solutions of AgCF₃ had to be freshly prepared from trifluoromethyltrimethylsilane and AgF in acetonitrile, because they were unstable and sensitive to both light and heat. The team investigated the reason for the improved stability and found that tBuOK is crucial to the stability of AgCF₃.

The researchers used the stable AgCF₃ solution in radical trifluoromethylation reactions, such as the hydrotrifluoromethylation of alkenes and the C–H trifluoromethylation of (hetero)arenes. The developed method also allows the conversion of HCF₂CF₃ into AgCF₂CF₃ for the synthesis of pentafluoroethylated products.

• Argentination of Fluoroform: Preparation of a Stable AgCF₃ Solution with Diverse Reactivities,
  Jia-Xiang Xiang, Yao Ouyang, Xiu-Hua Xu, Feng-Ling Qing,
  Angew. Chem. Int. Ed. 2019.
  https://doi.org/10.1002/anie.201905782