Explain nucleophilic substitution of alkyl halides?

1 Answer
Jan 10, 2015

Nucleophilic substitution of alkyl halides is the substitution of the halogen by another group called a nucleophile.

images.tutorvista.com

In most of the alkyl halides, the C-X bond is polar.

sydney.edu.au

That gives the α carbon a partial positive charge

The positive charge makes that carbon susceptible to attack by a nucleophile.

www.chemvista.org

In one scenario, called the #"S"_"N"2# mechanism, the halide leaves at the same time as the nucleophile attacks.

In a different scenario, the #"S"_"N"1# mechanism, the halide ion leaves first, forming a carbocation.

alevelchem.com

The nucleophile attacks the carbocation in a second step, forming the product.

Here's a video on the nucleophilic substitution of alkyl halides.