How Leaving Groups Affect Substitution

Leaving groups affect how nucleophilic substitution reactions happen. In this type of reaction, a nucleophile replaces a functional group on a substrate. The group that leaves is called the leaving group, and it departs when the bond breaks by heterolytic cleavage, taking both electrons with it.

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In a nucleophilic substitution reaction, a nucleophile displaces a functional group — called a leaving group — at the carbon atom in the substrate to give a substituted product.

A substrate with a good leaving group eases the displacement process and speeds up the reaction.

A leaving group departs the substrate through heterolytic ...