Organic Chemistry/Introduction to reactions/Overview of addition, elimination, substitution and rearrangement reactions
The real heart of organic chemistry is the reactions. Everything that you study is geared to prepare you for organic syntheses and other chemical transformations performed in the lab. This chapter gives you the basic tools to begin looking at these reactions.
Some basic reaction types[edit | edit source]
One way to organize organic reactions places them into a few basic categories:
- addition reactions
- elimination reactions
- substitution reactions
- rearrangement reactions
Other categories include:
Sometimes one reaction can fall into more than one category. These classifications are just a tool and are not rigid.
Addition reaction[edit | edit source]
Something is added to something else to produce a third thing.
- A + B → C
Note: the letters A, B and C here represent any atomic, ionic or molecular species which can undergo this type of reaction.
Elimination reaction[edit | edit source]
Something comes off of a molecule, resulting in two products.
- A → B + C
Substitution reactions[edit | edit source]
This involves the exchange of one group for another.
- AB + CD → AC + BD
Common reaction types include
- radical reactions and
- nucleophilic substitutions
- SN1, Unimolecular nucleophilic substitution
- SN2, Bimolecular nucleophilic substitution
Rearrangement reactions[edit | edit source]
A molecule shifts or otherwise rearranges to form a different molecule.
- A → B
This typically happens when one molecule changes into an isomer of itself.