Other metals have also been used to effect the Wurtz coupling, among them silver, zinc, iron, activated copper, indium and solomons organic chemistry pdf mixture of manganese and copper chloride. The related reaction dealing with aryl halides is called the Wurtz-Fittig reaction.
This can be explained by the formation of free radical intermediate and its subsequent disproportionation to give alkene. The Wurtz reaction occurs through a free radical mechanism. One electron from the metal is transferred to the halogen to produce a metal halide and an alkyl radical.
The alkyl radical then accepts an electron from another metal atom to form an alkyl anion. This intermediate has been isolated in several cases. The nucleophilic carbon of the alkyl anion then displaces the halide in an SN2 reaction, forming a new carbon-carbon covalent bond. Due to several limitations this reaction is seldom used.
For example, it is intolerant of a range of functional groups. Wurtz coupling is, however, useful in closing small, especially three-membered, rings.