Question

What is the correct IUPAC name of the following compound given below ?

• A. 6-propylocta-2,4-diene-8-yne
• B. 3-propylocta-4,6-diene-1-yne
• C. Propyl-3-octa-4,6-diene-1-yne
• D. 3-propylocta-4,6-dien-1-yne

Answer 1

The correct option is D 3-propylocta-4,6-dien-1-yne

If double and triple bond, both present in a structure with no other higher ranked substituent present , then while numbering Lowest locant set is chosen.
lowest locant is 1,3,4,6.

While naming polyenes and poly-ynes, alphabet ‘a’ will be added just after word root.

The correct numbering to longest chain is given by :

Hence, correct IUPAC name is
3-propylocta-4,6-dien-1-yne