An ew method for the on-site preparation of tetrafluoroethylene (TFE) and ap rocedure for its efficient use in pentafluoroethylation by fluoride addition were developed by using as imple two-chamber system. The on-site preparation of TFE was accomplished by dimerization of difluorocarbene derived from (trifluoromethyl)trimethylsilane (TMSCF 3 )u nder mild conditions.O ther fluoroalkylation reactions,s uch as (aryloxy)tetrafluoroethylation and tetrafluoroethylation processes,w ere also achieved using as imilar approach.T his work not only demonstrates ac onvenient and safe approach for the generation and use of TFE in academic laboratories,but also provides anew strategy for pentafluoroethylation.Organofluorine compounds are widely used as functional materials,a grochemicals,a nd pharmaceuticals owing to the unique physical, chemical, and biological features that result from fluorine substitution. [1] Therefore,d eveloping novel methods for the straightforward incorporation of per-o r polyfluorinated groups into organic molecules has received significant attention in both academia and industry. [2] Te trafluoroethylene (TFE, CF 2 =CF 2 ), as abulk fluorochemical for the industrial manufacture of poly(tetrafluoroethylene) and copolymers with other alkenes, [3] is an ideal C2 building block for incorporating fluorinated moieties such as -CF 2 CF 2 -, HCF 2 CF 2 -, and CF 2 = CF-into small molecules. [4] However, TFE is suspected to be carcinogenic, unstable towards radicals,a nd prone to explode when in contact with air,a ll of which in turn require that TFE gas is handled with extreme caution, including during storage and transport. [3d, 5] To overcome the inherent limitations associated with using TFE gas in academic laboratories,s everal TFE precursors have been developed that release TFE gas on site in small amounts.A vailable methods include the reduction of 1,2-dihalotetrafluoroethanes (XCF 2 CF 2 Y; X, Y = Br,Cl) with zinc powder [6] and the pyrolysis of sodium perfluoropropionate [3d] or poly(tetrafluoroethylene) [7] at high temperatures. However,t he restricted availability of XCF 2 CF 2 Ya nd the harsh conditions required for the pyrolysis reactions have limited the utilizations of these methods,thus preventing the development of fluoroalkylation reactions with TFE in common research laboratories.T herefore,t he development of practical and operationally simple methods for the laboratory preparation of TFE is highly desirable.TheRuppert-Prakash reagent (TMSCF 3 )isreadily available and is the most extensively used trifluoromethylation reagent for avariety of applications. [8] In 2011, our group and the Prakash group cooperatively developed an efficient method for the preparation of gem-difluorocyclopropa(e)nes by using TMSCF 3 as an ovel difluorocarbene source in the presence of NaI (Scheme 1a). [9] During the investigation, we noticed that TFE was normally formed as aside product (see the Supporting Information). [9a] In 2014, Baker and coworkers observed that am ixture of TMSCF 3 and NaI in THF cou...
