Question

IUPAC name of the compound is:

• A. Hex-1-ene-5-yne
• B. Hex-5-yne-1-ene
• C. Hex-1-en-5-yne
• D. None of the above

Answer 1

The correct option is C Hex-1-en-5-yne

Theory :

Nomenclature of alkenyne :

If double and triple bond, both present in a structure with no other higher ranked substituent present:

Note :

While numbering - lowest locant set is chosen.

In case of a tie - Alkene is preferred over alkyne in assigning number

While naming - 'ene' comes before 'yne' alphabetically

Terminal 'e’ is dropped if it is followed by the suffix beginning with alphabets a, i, o, u or y.

Hence, correct IUPAC name is Hex-1-en-5-yne