Name The Alkenes Below. (Z)-7-Butyl-1-Methylcyclooct-1-Ene 4-Tert-Buytlcyclohexene
The Correct Answer and Explanation is:
1. (Z)-7-Butyl-1-Methylcyclooct-1-ene
Correct Name:
(Z)-1-Methyl-7-butylcyclooctene
Explanation:
This compound is a cyclooctene ring (8-membered ring) with a double bond between carbon 1 and carbon 2. A methyl group is attached to carbon 1, and a butyl group is attached to carbon 7. The (Z) stereochemistry refers to the cis configuration of the higher-priority groups (methyl and butyl) on the double bond. According to IUPAC rules, substituents are numbered to give the double bond the lowest possible position. Since the double bond is at position 1, the methyl is at C-1 and the butyl at C-7. The correct name reflects the position of substituents and stereochemistry.
2. 4-Tert-Butylcyclohexene
Correct Name:
4-tert-Butylcyclohexene (already correctly named)
Explanation:
This compound consists of a cyclohexene ring (6-membered ring with one double bond). The tert-butyl group is attached to carbon 4. Numbering starts at one of the carbons of the double bond to give it the lowest possible number, which places the double bond between C-1 and C-2. From there, the tert-butyl substituent ends up at position 4. This name correctly follows IUPAC rules and needs no changes.
Summary:
| Given Name | Correct IUPAC Name |
|---|---|
| (Z)-7-Butyl-1-Methylcyclooct-1-ene | (Z)-1-Methyl-7-butylcyclooctene |
| 4-Tert-Butylcyclohexene | 4-tert-Butylcyclohexene |
Proper IUPAC naming involves identifying the longest carbon chain or ring, the position and type of double bond(s), and placing substituents at the correct positions with appropriate stereochemistry. The prefix (Z) indicates that the higher priority groups (based on CIP rules) on either side of the double bond are on the same side—this is the cis form.
