What is the IUPAC name of the following compound?
The structure is an alkene, that means, the first thing we'll need to do is find the longest chain containing the double bond.
- That's the blue highlighted chain containing 9 carbon
Then, we'll need to start counting from the end that is closest to the double bond.
- That's starting from the top rather than from the right. If we count following the labeled numbering, the double bond is between C4 and C5.
- However, if we count from the right, the double bond will be between C5 and C6. That's further away than C4-C5.
- So it's decided that it's non-4-ene.
Lastly, we'll place in the 2 substituents - ethyl at C4 and methyl at C8.
Putting everything together, the IUPAC name for this compound is 4-ethyl-8-methyl-non-4-ene .