Question

What is the best name for this molecule? Explain your naming process.

Answer 1

Hi!

The best possible name for this molecule would be: 4 - ethyl - 1 - heptene or 4 - ethylhept - 1 - ene

We always name the molecule with respect to the longest chain (in a branched molecule), taking both atoms of carbon participating in the double bond into account too. In our case, this gives us a 7 Carbon chain - hept

ene - is the suffix that is indicative of the molecule being an alekene.

So we know it is a branched heptene molecule

We add the number where the double bond occurs either before ene, or before heptene as a rule.

Note: We always start with the end of the chain from where the double bond is the closest, and number the carbons accordingly.

The title and position of the branch always comes at the start. In our case the branch is a two carbon chain, and an alkane, so it would be an ethyl branch. This branch occurs at carbon number 4

Hence, the correct names would be:

4 - ethyl - 1 - heptene or 4 - ethylhept - 1 - ene

Hope this helps!