Question

The IUPAC name of the compound CH3−CH3|CH−CH2−CH=CH−CH3 is .

• A. 5-methylhex-3-ene
• B. 2-methylhex-4-ene
• C. 5-methylhex-2-ene

Answer 1

The correct option is C 5-methylhex-2-ene

Shown below within the dotted lines is the parent chain of the given compound.

$\bullet$ The word root here is 'hex' as the parent chain contains 6 carbons in it.

$\bullet$ The numbering is assigned such that carbon atoms between which double bond is present gets the lowest number.

$\underset{6}{C}{H}_3-\underset{5}{\stackrel{C{H}_3}{\stackrel{|}{C}H}}-\underset{4}{C}{H}_2-\underset{3}{C}H=\underset{2}{C}H-\underset{1}{C}{H}_3$

$\bullet$ The primary suffix of the compound will be '-ene' since it has a double bond in the parent chain.

$\bullet$ The parent chain has a methyl group also attached to it and hence, the prefix of the compound will be 'methyl'.

$\bullet$ Thus, the IUPAC name of the compound is 5-methylhex-2-ene.