Having gone through the mechanism of the SN2 reaction, let’s take a second and look at why it might be useful. In nucleophilic substitution reactions, we’re trading a carbon-(leaving group) bond for a carbon-(nucleophile) bond. If we choose a good leaving group – i.e. an appropriately weak base – we can use this reaction with a *large* variety of nucleophiles.
Look at all the different functional groups you can make from just this one reaction!
Note – some of these substitution reactions work better than others, especially on secondary carbons – depending on conditions, elimination reactions can start to compete when strong bases are used. We’ll get there!