Ethers

Introductory IUPAC Organic Nomenclature

Ethers

Nomenclature	Formula	3D structure
Functional class name = alkyl alkyl ether e.g. ethyl methyl ether Substituent prefix = alkoxy- e.g. methoxyethane

Examples of how each of the types of nomenclature are applied are given below. No one method is more correct than the other, but some guidance on the common practices is given.

Note : the examples chosen are to illustrate the naming subsystem.

In practice, these examples would probably all be named as alkyl alkyl ethers.

"Simple" ethers

If both groups are simple alkyl groups, then the ether is usually named as alkyl alkyl ether
The alkyl groups are listed in alphabetical order
If the two alkyl groups are the same, then it's a dialkyl ether

Functional group is a simple ether, therefore use alkyl alkyl ether
First substituent is C1 alkane therefore alkyl = methyl
Second substituent is C2 alkane therefore alkyl = ethyl

ethyl methyl ether

CH₃CH₂OCH₃

Functional group is a simple ether, therefore use alkyl alkyl ether
Both substituents are C2 alkane therefore alkyl = ethyl
Since there are two alkyl groups, multipler = di

diethyl ether

CH₃CH₂OCH₂CH₃

"Intermediate" ethers

If one of the groups is more complex then the ether group is usually treated as an alkoxy (i.e. R-O-) substituent.
The more complex group (i.e. longer chain, more branched, other substituents) defines the root.

Hydrocarbon structure is an alkane therefore -ane The longest continuous chain is C3 therefore root = prop Substituent is C1 alkane therefore alkyl = methyl The first point of difference rule requires numbering from the right as drawn to make the group locant 1- 1-methoxypropane	CH₃CH₂CH₂OCH₃
Hydrocarbon structure is an alkane therefore -ane The longest continuous chain is C3 therefore root = prop Substituent is C1 alkane therefore alkyl = methyl Numbering makes the group locant 2- 2-methoxypropane	CH₃CH(OCH₃)CH₃