Basic Organic Nomenclature

Alkynes and Alkenes Combined

Family name: suffix: -enyne

The final possibility is the combination of both double and triple bonds in a compound. The double bonds are indicated by adding the -ene suffix to the root name. The triple bond is indicated by dropping the final e of the -ene suffix, and appending the -yne suffix to the end of the name. The location of the double bond is indicated by a number preceding the root name, and the location of the triple bond is indicated by placing the number before the yne suffix ( i.e. 2-hexen-4-yne).

Again, locate the longest chain (or ring) which contains all of the carbon atoms of all multiple bonds (i.e. both double and triple bonds). The chain (or ring) is then numbered from the end with the closest multiple bond. Substituents are then located according to this numbering scheme. If there is no preferred numbering scheme due to the multiple bonds (i.e. the multiple bonds are the same distance from the ends of the chain), then the numbering scheme that gives the double bond the lowest number is used. Rings are treated the same way, but note, one of the multiple bonds will always start at carbon 1, then number around the ring, the shortest distance, to the other multiple bond(s). (Note: it requires a large ring to contain multiple triple bonds as they are linear.)

The presence of the multiple double or triple bonds are indicated in the name by: first, the number locating each double or triple bond present; second, by adding the di, tri, tetra, ... prefixes before the -en or -yne ending. NOTE: you need to add an "a" before the di, tri, etc.

Examples of naming alkenynes are:

Compound Name
Line Drawing
3D Model
1-buten-3-yne
or
buten-3-yne
4-methyl-3-hexen-1-yne
or
4-methyl-3-hexenyne
1,2-heptadien-4,6-diyne
Tutorial Quiz: Alkynes

Next Page: Ethers

Return to Index