Reaction with perfluoroalkylcopper

Table 6, Perfluoroalkyl Aromatic Compounds Prepared via the Reaction of Perfluoroalkylcopper Reagents with lodo-or Bromoaromatic Compounds...

Coupling of aryl iodides has also been effected with perfluoroalkylcoppers and perfluo-rovinylcopper reagents51,13. The former reaction may also be accomplished by employing the perfluoroalkylsilane, the aryl iodide and stoichiometric amounts of KF2. Trifluoromethylation may also be accomplished, in more modest yields, by decarboxylation of sodium trifluoroacetate in.the presence of Cul and an aryl iodide71. Stannylation has been accomplished of aryl halides by the use of h.o. stannylcyanocuprates (equation 50)72. 

The reaction of perfluoroalkylcopper compounds, prepared in situ from the perfluoroalkyl iodide and copper, with ip -hybridized organic halides [Eq. (73)] in refluxing pyridine utilizes the thermal stability of the intermediate copper compounds and their failure to react with sp -hybridized halides (29, 30). 

Perfluoroalkylcopper reagents are the most studied perfluoroalkyl organometallic reagents due to their unique combination of thermal stability and chemical reactivity. They are readily prepared by copper metal insertion reactions with perfluoroalkyl halides in a coordinating solvent (e.g., formation of decarboxylation reactions of perfluoroalkanoic acid salts and copper(I) halide (e.g., formation of 2 ), or metathesis reactions (e.g., formation of 4 via 3 ). (Trifluoro-methyl)copper (4) has also been recently accessed by decomposition of methyl 2,2-difluoro-2-(fluorosulfonyl)acetate (5) or methyl perfluoro [2-(fluorosulfonyl)ethoxy]acetate (6) in the presence of copper(I) iodide and by reaction of trimethyl(trifluoromethyl)silane (7) with fluoride and copper(I) iodide. ... 

Perfluorovinyl iodides readily undergo stereospecific coupling with the tn-fluoroinethylcopper solution [224] (equation 151) prepared from dibromodifluo-romethane [210] With longer-chain perfluoroalkylcopper reagents, the coupling reaction is accompanied by some exchange processes [225] (equation 152)... 

Perfluoroalkylcopper reagents couple with 1-iadoacetylenic derivatives to give the expected perfluoroalky(-substituted acetylenes [226] (equation 153) The coupling reaction is complicated by formation of the diyne from competitive exchange processes... 

Numerous perfluoroalkyl-substituted arenes have been prepared by the coupling of aryl iodides or bromides with perfluoroalkyl iodides in the presence of copper bronze in a dipolar aprotic solvent at elevated temperatures. Perfluoroalkyl bromides and chlorides can be utilized in similar reactions provided a bidentate ligand such as 2,2 -bipyridyl or 1,10-phenanthroline is added 199, 278). Perfluoroalkylcopper reagents are believed to be intermediates in the couplings 200, 201). 

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