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Examples of reactions involving leaving groups in organic chemistry

Learning Objective: To study the various examples of organic reactions where the leaving group departs from a molecule and also understand its various types.

Prerequisites: 

Chapter: Fundamentals of Organic Reactions

Sub-topic: Leaving Groups

Author's Note: Once the what and why of a leaving group is understood, the next level in learning would be to see examples of reactions where they are seen most often. I have shortlisted two reaction categories- the substitution and elimination types of reactions with examples to reinforce the concept. You can see how connected the nature of incoming and outgoing groups are; for example, if an incoming group is a nucleophile, the outgoing group is a nucleofuge. Also included are the examples of leaving groups most common to organic chemistry. 

Examples of leaving groups in organic reactions

Displacement and elimination reactions thrive on leaving groups’ ability to cleave easily and not reconnect; otherwise, the reactions would go in a circle.

Displacement Reactions

The leaving groups are part of SN1 and SN2 types of displacement reactions featuring alkyl substrates. 

In SN1 reactions, the leaving group leaves before the incoming group approaches indicating a push from.... 

  • Carbon leaving group
  • Sulfur leaving group
  • Halogen leaving group.....

 

Elimination reactions

If substitution reactions replace one group with another, elimination reactions discard atoms. There is no incoming group, only an outgoing group of atoms.

Example of Leaving group in E1 type of reaction

 

Subscribe to read about the reactions in organic chemistry where you would commonly encounter a leaving group. 

 

Fundamentals of Organic Reactions
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