Provide systematic name for given alkene.

• A. trans-2,7-dimethyl-3-octene
• B. 2,7-dimethyl-3-octane
• C. trans-2,7-dimethyl-5-octene
• D. 2,7-dimethyl-5-octane

Answer: (A)

Verified step by step guidance

1. Identify the longest carbon chain that contains the double bond. In this structure, the longest chain has 8 carbon atoms, so the base name will be 'octene'.
2. Number the carbon chain from the end nearest the double bond to give the double bond the lowest possible number. Here, numbering from left to right gives the double bond at carbon 3, so the name includes '3-octene'.
3. Identify and locate the substituents attached to the main chain. There are two methyl groups attached at carbons 2 and 7, so the substituents are '2,7-dimethyl'.
4. Determine the stereochemistry of the double bond. Since the two methyl groups on the double-bonded carbons are on opposite sides, the configuration is 'trans'.
5. Combine all parts of the name: the stereochemistry prefix 'trans-', the substituent locations and names '2,7-dimethyl-', and the base name with the double bond position '3-octene', resulting in 'trans-2,7-dimethyl-3-octene'.