Question

According to IUPAC system, the compound

• A. Cyclohex-1-en-2-ol
• B. 1-Hydroxyhex-2-ene
• C. Cyclohex-1-en-3-ol
• D. Cyclohex-2-en-1-ol

Answer 1

The Correct Option is D

The compound shown in the image is a substituted cyclohexane. To name it according to the IUPAC system, follow these steps:

1. Identify the longest carbon chain that includes the highest priority functional group, which in this case is the hydroxyl group (-OH).
2. Number the carbon atoms in the ring starting from the carbon to which the -OH group is attached and moving in the direction that gives the double bond the lowest possible number. Here, the -OH group gets priority due to its higher precedence over the alkene.
3. Assign numbers:
   • The hydroxyl group (-OH) is attached to carbon 1. 
   • The double bond starts at carbon 2.
4. Combine the information to form the name:
   • The name will include "cyclohex" due to the six-carbon ring.
   • Use "en" to denote the double bond starting at carbon 2.
   • Use "ol" to indicate the presence of the hydroxyl group at carbon 1.

Therefore, the correct IUPAC name for the compound is Cyclohex-2-en-1-ol.

Let's rule out the other options:

• Cyclohex-1-en-2-ol: Incorrect numbering, as the double bond should be at carbon 2.
• 1-Hydroxyhex-2-ene: This suggests an open chain structure, not a cyclic one.
• Cyclohex-1-en-3-ol: Incorrect numbering for the placement of -OH and the double bond.

Hence, the correct answer is Cyclohex-2-en-1-ol.

Answer 2

The compound has a hydroxyl group (-OH) attached to the first carbon in the cyclohexene ring, and the double bond is at the second carbon. According to IUPAC nomenclature: - The base name ”Cyclohex” comes from the cyclohexane ring. - The double bond is between positions 2 and 3, so we have ”Cyclohex-2-en”. - The hydroxyl group is at position 1, so the name ends with ”1-ol”. Thus, the correct IUPAC name is ”Cyclohex-2-en-1-ol”.
The Correct Answer is: Cyclohex-2-en-1-ol