Answer
The name of the compound is 2,3,4-trimethyl-6-phenyl-4-octene.
Work Step by Step
The longest carbon chain has 8 carbon atoms (-oct). It is an alkene since it has a double bond at position 4. It has 3 methyl substituents, one each at positions 2,3 and 4. The benzene ring acts as a substituent (phenyl) at position 6. Hence, the name of the compound is 2,3,4-trimethyl-6-phenyl-4-octene.
