108 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.

108.1 Some basic reaction types

One way to organize organic reactions places them into a few basic categories:

• addition reactions


• elimination reactions


• substitution reactions


• rearrangement reactions

Other categories include:

• Oxidations


• Reductions


• Alkylations

Sometimes one reaction can fall into more than one category. These classifications are just
a tool and are not rigid.

108.2 Addition reaction.

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.

108.3 Elimination reaction

Something comes off of a molecule, resulting in two products.

A → B + C