Ethynylcopper compounds, reactions with

Castro et al. 44) found that the order of reactivity of various halides in coupling reactions with ethynylcopper compounds in DMF is ArSX, ArX > RCOX ArCHaX, RCH=CHCH2X, ArCOCHaX > RCH= CHX, Alkyl-X. A somewhat different order is observed for the reactivity of some organic halides towards perhaloarylcopper reagents in THF (97, 147) Allyl Aryl > Alkyl and perfluoroaryl, perfluoro-vinyl > aryl > perfluoroalkyl. Acid halides were also far more reactive than aryl iodides in ethereal solvents 146). The ease of halide displacement is I > Br > Cl. 

Organocopper compounds couple readily with allyl halides under mild conditions. In some instances the reactions are reported to be vigorous. Coupling of ethynylcopper compounds with allyl halides can be effected at the ambient temperature in the presence of halide or cyanide ligands 221). Isolation of some rearranged coupling products in certain reactions 44, 66) may indicate the intermediacy of allylcopper(III) species. The reactions are summarized in Table VII. 

Reactions between ethynylcopper compounds and some transition metal complexes afford unusual types of polynuclear heteroatom complexes. The reaction of phenylethynylcopper with IrCl(CO)[P(CgH5)3]2... 

Tetracyanoethylene reacts with four equivalents of phenylethynyl-copper in THF at 55°C to give (phenylethynyl)tricyanoethylene and tar 281). Other ethynylcopper compounds in similar reactions gave either the dimer of the copper compound or a compound of empirical formula CuCa(CN)a which may be a chelate polymer joined by copper atoms. 

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