Organic Alkane Naming

1 Carbon Atom

Methane/Methyl

2 Carbon Atoms

Ethane/Ethyl

3 Carbon Atoms

Propane/Propyl

4 Carbon Atoms

Butane/Butyl

5 Carbon Atoms

Pentane/Pentyl

6 Carbon Atoms

Hexane/Hexyl

7 Carbon Atoms

1st Step Naming Alkanes

Identify longest (Parent) chain of carbons

If there is competition, choose the chain with the most substituents

Cyclo

Indicates the presence of a ring in the alkane structure

When an alkyl group (substituent) is connected to a ring, the ring is generally treated as the parent

If the ring is comprised of fewer atoms than the rest, it is instead considered a substituent (cycloalkyl group)

2nd Step Naming Alkanes

List and number all substituents

If 1 substituent is present, it should be assigned the lowest number possible

When multiple substituents are present:

• give the first the lowest number possible (2,5,5) vs (3,6,6)

• If there is a tie, the second should be the lowest possible

• If there is still a tie, assign the lowest number alphabetically

If a substituent appears more than once in a compound, a prefix is used to identify how many times it appears:

• di = 2

• tri = 3

• tetra = 4

• penta = 5

• hexa = 6

Naming Complex Substituents

Place numbers on the substituent going away from the parent chain

Assembling the Systematic Name

Place all substituents in alphabetical order (prefixes except iso don’t count)

hyphens separate numbers from letters & commas separate numbers from each other

Isopropyl

sec-butyl

Isobutyl

tert-butyl

Isopentyl/Isoamyl

Neopentyl