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Wurtz reaction

Wurtz reaction is coupling of haloalkanes using sodium metal in solvent like dry ether

\[2R-X + 2Na \rightarrow R-R + 2Na^+X^−\]

The reaction consists of a halogen-metal exchange involving the free radical species R• (in a similar fashion to the formation of a Grignard reagent and then the carbon-carbon bond formation in a nucleophilic substitution reaction.)

One electron from the metal is transferred to the halogen to produce a metal halide and an alkyl radical.

\[R-X + M → R^{\cdot} + M^+X^−\]

The alkyl radical then accepts an electron from another metal atom to form an alkyl anion and the metal becomes cationic. This intermediate has been isolated in a several cases.

\[R^{\cdot} + M → R^−M^+\]

The nucleophilic carbon of the alkyl anion then displaces the halide in an SN2 reaction, forming a new carbon-carbon covalent bond.

\[R^−M^+ + R-X → R-R + M^+X^−\]