Pentafluorophenyl copper

The pentafluorophenylcopper tetramer is usually analytically pure as isolated and melts at 200° with decomposition. If any significant decomposition occurs during the final drying, the product can be purified by dissolution in ether, filtration to remove copper metal, and precipitation by addition of hexane. It can also be recrystallized from benzene. When kept in a sealed container under nitrogen at room temperature, pentafluorophenyl copper tetramer appears to be stable for reasonable periods. It can be stored indefinitely at -78° under an atmosphere of carbon dioxide. 

The nature of organocopper reagents appears to be dependent on the method of preparation and the stoichiometry. Specific examples are methylcopper (76, 310), phenylcopper 73), and pentafluorophenyl-copper 34, 37, 147). The best method of preparing pentafluorophenyl-copper of composition CeFsCu appears to be via the addition of copper(I) bromide to pentafluorophenylmagnesium bromide 34, 37), since the lithium reagent and copper iodide gives an ate complex 147). An ate complex was also obtained from pentafluorophenyllithium and silver chloride in equimolar proportions 265). As shown in Table III, many of the isolated copper compounds gave somewhat incorrect or irreproducible analyses, and others contain metal halide and solvent molecules. 

Poor yields of ketones were obtained from the reaction of dialkylcuprates with levulinoyl chloride (233), and from pentafluorophenyl-copper and malonyl chloride (115, 180). The yields of the ketones from the reaction of polyhaloarylcopper reagents with succinoyl chloride were also lower than those from a number of other diacid chlorides (101). Acidic hydrogen atoms are the most likely source of trouble in these reactions. 

A practical route to aporphine-benzylisoquinoline dimers by an improved Ullmann diphenyl ether synthesis has been worked out. The aromatic halide and the phenolic compound are heated with pentafluorophenyl copper in dry pyridine the average yield of dimer being 50%. ... 

Bromolaudanosine undergoes a reatively easy Ullmann coupling with phenols in solution in pyridine in the presence of tetra(pentafluorophenyl)copper. Using this reaction between the bromo-alkaloid and phenolic benzylisoquinolines and apor-phines unnatural bisbenzylisoquinolines, such as (87), have been prepared from armepavine and (88) from iv-methylcassyfi-line (Cava and A. Afzali, J.org.Chem., 1975, 1553). 

In a new modification of the Ullmann procedure. Cava and Afzali have found that condensation of equimolar amounts of 5-( + )-6 -bromolaudanosine with iS -(+)-armepavine in pyridine in the presence of pentafluorophenyl-copper (PFPC) gave (-l-)-O-trimethylmagnolamine in 427 yield. This reaction was then extended to the aporphine-benzylisoquinoline series. ... 

The active copper as generated in the preceding text was allowed to react with pentafluorophenyl iodide (molar ratios of 3.3 1) at room temperature in DME for 30 min. The supernatant solution was then anaerobically transferred to another flask, where the solvent and excess aryl iodide were removed under vacuum to leave a tan solid containing pentafluorophenyl copper. This tan solid was difficult to purify however, its chemistry matches that published for pure pentafluorophenyl copper. Yields were in the range of 70-80%. 

Other unsupported copper(I)-copper(I) interactions include those in (HjN)CuX (X = Cl, Br) [47], in the pyridine adduct of (pentafluorophenyl)copper [48], and in the surprising approach of... 

The arylcopper reagents couple with 1-iodoarylacetylenes to give the unsym-metrical diarylacetylenes [25(S] (equation 176) Reaction with tetrabromoethyl- ene gives bis(pentafluorophenyl)acetylene in 66% yield [25S] (equation 177) Pen-tafluorophenyl copper couples with (bromoethynyl)triethylsilane to give C6F5C=CSi(C2H5)3 in 85% yield [259]... 

Copper, (pentafluorophenyl)- (8, 9) (18206-43-4) Pentafluorophenylmagnesium bromide Magnesium, bromo(penta-fluorophenyl)- (8, 9) (879-05-0)... 

Matsubara and Yoshida have shown that 9,10-di(pentafluorophenyl)anthra-cene can be synthesized by a copper-catalyzed arylation of pentafluorobenzene with dibromoanthracene [105], The reaction is only successful if silver oxide base is used. 

Scheme 4.26 shows the development of two general reactions based on copper(I) thiophene-2-carboxylate (CuTC) or Cu(OAc)2 for the formal arylation of imtnes with arylboronic acids [62]. The O-acetyl or O-pentafluorophenyl oximes react with a wide range of electron-rich, electron-poor and electron-neutral boronic acids, and even ortho-substituted substrates react well. The mechanism is proposed to proceed, as shown in Scheme 4.27, via an initial oxidative addition of the copper(I) species, either CuTC or through reduction of Cu(OAc)2 by the boronic acid, to the ketoxime O-carboxylate. This is followed by transmetallation and reductive elimination to generate the final product and regenerate the catalytically active copper(I) species. 

Figure 10.12 2,17-Bis-sulfonato-5,10,15-tri(pentafluorophenyl)corrole manganese complex 14 [59,60], tetrakis(sulfonato) phthalocyanin copper complex 15 [61], and meso-tetrakis (p-carboxyphenyl)-porphyrln manganese complex 16 [62].

Bis(pentafluorophenyl)sulphide, (QF6)2S, may be prepared from bromopentafluorobenzene and copper(i) pentafluorobenzenethiolate in DMF . The use of the copper salt eliminates the need to generate the pentafluorobenzenethiolate anion, QFgS, in basic solution. The copper-assisted nucleophilic displacement reactions of halopentafluorobenzenes have been studied . The reaction of CuSBu with QFgBr gave two products... 

Reaction of K-Generated Copper with Pentafluorophenyl Iodide... 

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