This Review chronicles the progress made in the field of small fluorocarbon synthesis since their invention in the early 1930s by Thomas Midgley, Jr., and his coworkers, with special focus on their application as refrigerants, foam expansion agents, aerosol propellants, and precision solvents. Divided into four generations of C1–C4 halocarbons from CFCs through HCFCs, HFCs, and HFOs, the merits and challenges of each will be discussed in the context of market demands, as well as the evolution of industrial manufacturing methods. Vital transformations, such as exchange (Swarts) fluorination, hydrodehalogenation, dehydrohalogenation, and additions (Kharasch or Prins) will feature prominently and will be discussed in detail, as well as catalysts therefor. Of the myriad of fluorocarbons described herein, the models which have reached particular commercial significance (such as chlorodifluoromethane and 1,1,1,2-tetrafluoroethane) are given special consideration as flag-bearers for the generation to which they belong. Regulatory constraints to which this industry is bound will be outlined in brief, as well as an introduction to safety designations and nomenclature put forth by the American Society for Heating, Refrigerating, and Air-Conditioning Engineers (ASHRAE). This Review includes predominantly works which can only be found in the patent literature, but should be of equal interest to both academic and industrial practitioners of the art as it centers on fundamentals of organofluorine chemistry, which could equally be applied to the synthesis of larger molecules and building blocks for other applications.

The reactivity of this T-shaped perfluoronickelacyclopentane–NHC complex with Lewis- and Brønsted acids is enhanced vs. 4-coordinate variants by its low coordination number.

There is an ongoing effort in the catalysis community to replace precious metal catalysts with their base-metal congeners, especially by applied chemists. This is particularly true in the case of nickel and palladium, the latter of which has experienced supply shortages and a concomitant rise in price over the past year. Ni(cod) 2 (cod = 1,5-cyclooctadiene) continues to be the flag-bearing precatalyst for nickel-catalyzed transformations on account of its versatility and commercial availability, but is plagued by diseconomies originating from limited shelf life and air/temperature sensitivity. The inconsistent purity of Ni(cod) 2 samples over time introduces an element of uncertainty in small-scale catalytic reaction tests such as those employed in highthroughput experimentation (HTE). We provide herein a method by which high-quality 1-g batches of Ni(cod) 2 can be prepared easily in 20 min using no pyrophoric reagents, allowing HTE studies with this catalyst to be performed directly after its preparation, reducing such uncertainty.

Hydrofluoroolefins (HFOs) constitute the newest generation of fluorocarbon refrigerants and foam-blowing agents due to their reduced global warming potential vs their saturated analogues. To identify new synthetic routes to HFOs, we show that reactions of bulky Ni(0) phosphine and −NHC complexes with vinylidene difluoride (VF2) afford μ-fluoro-1,1,3-trifluorobut-3enyl Ni complexes. Moreover, addition of triisopropylsilane allows for reductive elimination of the reduced product�2,4,4-trifluoro-1-butene�demonstrating the Ni-catalyzed hydrodefluorodimerization of VF2. Accompanying DFT calculations identify the Tshaped nickelacyclopentane intermediate that spontaneously undergoes selective intramolecular β-F (vs β-H) elimination.

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