Wurtz coupling Zinc-copper couple

In addition to sodium, other metals have found application for the Wurtz coupling reaction, e.g. zinc, iron, copper, lithium, magnesium. The use of ultrasound can have positive effect on reactivity as well as rate and yield of this two-phase reaction aryl halides can then even undergo an aryl-aryl coupling reaction to yield biaryls. ... 

The preparation of succinic esters by anion coupling with polyhalides has been described/ The scope of the Wurtz coupling of a-halogenoesters to give alkyl-substituted succinic esters has been investigated optimum conditions utilize a-bromoesters and zinc in THF, the presence of copper(n) salts being mandatory to avoid Dieckmann-type condensation to form p-ketoesters. 

However, the coupling of two aryl halides with sodium is impractical (but see 13-11). Other metals have also been used to effect Wurtz reactions, notably silver, zinc, ° iron, activated copper, In, and manganese com-... 

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