Arylations copper trifluoroacetate

Arylation. Copper(II) trifluoroacetate was used to perform the arylation of indoles with triphenylbismuth bis-trifluoroacetate. Products bearing a C3 phenyl group were obtained with Cs-unsubstituted indoles (eq4) and IV-phenyl derivative with carbazole. 

Arylthallium bis(trifluoroacetates) (see 12-21) can be converted to aryl nitriles by treatment with copper(I) cyanide in acetonitrile. Another procedure uses excess aqueous KCN followed by photolysis of the resulting complex ion ArTl(CN)3 in the presence of excess KCN. Alternatively, arylthallium acetates react with Cu(CN)2 or CuCN to give aryl nitriles. Yields from this procedure are variable, ranging from almost nothing to 90 or 100%. 

A hydroxy and an arylthio group can be added to a double bond by treatment with an aryl disulfide and lead tetraacetate in the presence of trifluoroacetic acid." Manganese and copper acetates have been used instead of Pb(OAc)4. ° Addition of the groups OH and RSO has been achieved by treatment of alkenes with O2 and a thiol (RSH)." Two RS groups were added, to give vie- dithiols, by treatment of the alkene with a disulfide RSSR and Bp3-etherate."° This reaction has been carried... 

Due to the cost of trifluoromethyl iodide, other cheaper sources have been investigated for trifluoromethylation. Sodium trifluoroacetate reacted with aryl iodide in the presence of copper (I) iodide in NMP at 140 -160 °C to afford the corresponding coupling product [87]. No trifluoromethylation was observed without Cul. Under similar reaction conditions, sodium pentafluoropro-pionate worked well to give the pentafluoroethylated compounds [88, 89] (Scheme 28). 

There is continued expansion in the use of metals as catalysts in substitution reactions. Copper iodide in the presence of /V./V -dimcthylcthylcncdiamine has been shown to be effective in the intramolecular substitution of aryl bromides carrying an o-l,3-dicarbonyl substituent reaction may involve either an oxygen centre or a carbon centre of the dicarbonyl moiety.26 The reaction of aryl halides with sodium trifluoroacetate in the presence of copper iodide may lead to the formation of the tri-fluoromethylated derivatives, possibly via CF3CuI as an intermediate.27 There have been theoretical calculations, PM3 and ab initio, on complexes formed from copper... 

The aryl chlorides and aryl bromides are easily prepared by treatment of the arylthallium(III) bis(trifluoroacetates) with the corresponding copper(I) or copper(II) halides. The best yields were obtained with the copper(II) halides in dioxane under reflux. 2 These reactions have been successfully applied by Somei et al to the synthesis of indole derivatives by reaction of the arylthallium compounds with copper(II) salts in DMF. 127,133,134... 

Enols and 1,3-dicarbonyl compounds undergo arylation in a manner similar to phenols. Triphenylbismuth bis(trifluoroacetate) in the presence of metallic copper and tetraphenylbismuthonium trifluoroacetate under acidic conditions are both effective for the selective 0-phenylation of enols and 1,3-dicarbonyl compounds [81CC503, 82TL3365, 85JCS(P1)2667, 86TL3619]. 

Itami has reported that electron-rich arenes can be arylated by arylboronic acids in the presence of stoichiometric copper(II) trifluoroacetate [ 103 ]. Trimethoxybenzene, indole, and pyrrole were shown to be reactive. Reactions proceed in dichloromethane in the presence of trifluoroacetic acid. 

Aryl radicals, that is, CeHs, which have been generated thermally by the decomposition of, for example, aryl diazonium salts (ArN2 ) in the presence of copper(I) salts (Equation 6.113) and the decomposition of diacyl peroxides (Equation 6.114), or photolytically from aryl iodides (e.g., iodobenzene, CeHsl) (Equation 6.115) and arylthallium trifluoroacetates as shown in Equation 6.116, react with benzene (CeHe) to give biphenyl (CeHs-CeHs) (Scheme 6.97). 

Cross-coupling. Copper(II) trifluoroacetate has been demonstrated to mediate the C-H bond arylation of arenes with arylboronic acids. Various arylboronic acids reacted with electron-rich benzene derivatives to give the corresponding biaryls in moderate to good yields (eq 1). In all cases, the cross-coupling product was solely obtained. 

Multiple C-H bond arylation is also possible. Copper(II) trifluoroacetate catalyzed the reaction of V-methylindole with phenyl boronic acid to afford the double arylated product in moderate yield (eq I) ... 

The room teiiq erature reaction of simple aliphatic ketones with an aqueous solution of thalllum(III) chloride leads to the formation of the mono-oxoalkylthalllum(III>. derivatives (23) which are then converted to selectively monochlorinated a-monochlorlnated ketones (Scheme 9> . Methyl vinyl ketone Is 8 arylated by arylthalllum conq>ounds In a reaction which Is catalysed by lithium tetrachloropalladate (Scheme 10) . The thallatlon of anilides with thalllum(III) trifluoroacetate In a mixture of trlfluoroacetlc acid and ether affords the ortho-thallated derivatives (24>, which yield 2-acetamldotolanes on reaction with copper(I> phenylacetyllde In acetonitrile. Ortho-... 

---