IUPAC Nomenclature Alkenes

Naming (Non-cyclic) Alkenes

Prefix-Locant-Parent-Suffix

Step 1

Locate and name the longest chain of carbons, which includes the C=C. Replace the normal -ane ending with -ene. For example:



Step 2

Number the carbons in the chain, starting at the end nearest to the double bond. If both ends equidistant, start at the end nearest to the first substituent. For example:



Step 3

Write the full name.

-Identify and label stereochemistry of the double bond (ex. cis-, trans-, etc.)

-List substituents alphabetically with the number of the parent chain carbon the substituent is attached to

-Number the carbon the double bond first occurs at