Hydrofluoroethers (HFEs): A History of Synthesis

An overview of the synthesis and applications of hydrofluoroethers (HFEs) is presented, structurally defined within this chapter as –(CF2)1–4–O–alkyl. First, an exhaustive summary of the commercial uses of HFEs is given along with the synthetic steps to achieve the incorporation of an HFE within its specific applications. Particular applications included are herbicides, insecticides, growth promoters in agriculture, blowing agents, cleaners, heat transfer fluids, protective coatings, and electrolytes in industry, and anesthetics, anti-inflammatories, and autoimmune and antitumor agents in medicine, to name just a few. Beyond applications, it is also important to understand the life cycle of HFEs in the environment; therefore, both biological and chemical reactivities of HFEs are provided. In addition, conventional strategies for the preparation of HFEs are outlined with many examples of, but not limited to, alkylation of fluorinated alkoxides, Suzuki–Miyaura coupling, oxycuperation of fluoroalkenes, and fluorination to thionyl esters with a wide range of fluorinating agents. The latter part of the chapter provides synthetic methodology to incorporate functionality on the fluorinated portion of the HFE ranging from amines to sulfonyl fluorides, and also including di- to multifunctional reports of HFEs. This overview summarizes current fields, emphasizing structural variety, end-group functionalities, and a range of synthetic methodologies to inform researchers on the manner in which new materials for current and future needs can be created.