FITJEE
Last Activity: 12 Years ago
he mechanism of the reaction goes like this :
One electron from the metal is transferred to the halogen to produce a metal halide and an alkyl radical.
- R-X + M → R• + 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• + M → R−M+
The nucleophilic carbon of the alkyl anion then displaces the halide in another molecule through a SN2 reaction, forming a new carbon-carbon covalent bond.
- R−M+ + R-X → R-R + M+X−
(from wikipedia)
so in the third step, there is SN2 reaction. tertiary alkyl group are very large groups. the alkyl anion will not be able to attack another molecule of the alkyl halide due to steric hindrance or repulsion between molecules. so tertiary alkyl halides do not give this reaction.