Question

What is the correct IUPAC name of the compound?

$C{H}_2=CH-C{H}_2-C\equiv CH$?

• A. 1,4-Pentenyne
• B. Pent-1-en-4-yne
• C. Pent-1-yn-4-ene
• D. 1, 4-Pentynene

Answer 1

The correct option is B

Pent-1-en-4-yne

While naming, the double bond gets a lower number than the triple bond.

$\underset{1}{C}{H}_2=\underset{2}{C}H-\underset{3}{C}{H}_2-\underset{4}{C}\equiv \underset{5}{C}H$

Wort root = pent

Pent-1-en-4-yne

Not 4-Penten-1-yne

Because, if there is a choice in numbering, the double bond is always given preference over the triple bond.