Question

The IUPAC name of the following compound is:

• A. 4-Hydroxyhept-1-en-6-yne
• B. 4-Hydroxyhept-6-en-1-yne
• C. Hept-6-en-1-yn-4-ol
• D. Hept-1-en-6-yn-4-ol

Hint:

When naming organic compounds, identify and number the substituents, functional groups, and multiple bonds to derive the correct IUPAC name.

Answer 1

The Correct Option is D

The objective is to determine the IUPAC name for the provided chemical structure. The nomenclature process follows these steps:

1. The principal chain consists of seven carbon atoms, dictating the parent name "heptane."
2. The molecule features both a double bond and a triple bond. IUPAC guidelines mandate numbering the chain to assign the lowest possible locant to the first multiple bond encountered. In this case, numbering from the right assigns position 1 to the double bond and position 6 to the triple bond.
3. Numbering from the right (CH₂=CH-CH₂-CH(OH)-CH₂-C≡CH) results in the double bond being at position 1 (indicated by "-en") and the triple bond at position 6 (indicated by "-yn").
4. The hydroxyl group (-OH) is treated as a substituent, located at carbon atom 4 (indicated by "4-ol").

Consequently, the correct IUPAC nomenclature for this compound is "Hept-1-en-6-yn-4-ol."

Critique of alternative nomenclature:

• 4-Hydroxyhept-1-en-6-yne: This is incorrect because the numbering does not properly prioritize the double and triple bonds according to IUPAC rules.
• 4-Hydroxyhept-6-en-1-yne: This is incorrect due to improper locant assignment for the double and triple bonds.
• Hept-6-en-1-yn-4-ol: This is incorrect as it prioritizes the triple bond's position over the double bond's.