The correct IUPAC name of
`{:(H_(2)C=CH-CH-CH_(2)C-=CH),(" |"),(" "CH_(3)):}`

Options

A. 3-methyl-1-hexen-5-yne
B. 4-methyl-5-hexen-1-yne
C. 4-(ethenyl)-1-pentyne
D. 3-(2-propenyl) butene-1

Answer

To determine the correct IUPAC name for the compound given, we will follow these steps:

### Step 1: Identify the longest carbon chain
The structure provided has a total of 6 carbon atoms. The longest continuous chain of carbon atoms is from the first carbon (C1) to the sixth carbon (C6).

### Step 2: Identify the functional groups
The compound has:
- A double bond (alkene) between C1 and C2.
- A triple bond (alkyne) between C5 and C6.
- A methyl (−CH3) group attached to C3.

### Step 3: Number the carbon chain
We will number the carbon chain from the end closest to the first double bond. This means:
- C1: CH2 (double bond)
- C2: CH
- C3: CH (with a methyl group attached)
- C4: CH2
- C5: C (triple bond)
- C6: CH

### Step 4: Assign the positions of the double and triple bonds
- The double bond is located at position 1 (C1=C2).
- The triple bond is located at position 5 (C5≡C6).

### Step 5: Combine the information for the IUPAC name
According to IUPAC nomenclature rules:
- The base name for a 6-carbon alkene is "hexene".
- Since the double bond is at position 1, we write "1-hexene".
- The triple bond at position 5 indicates it is also an alkyne, so we add "5-yne".
- The methyl group at position 3 is indicated by "3-methyl".

### Step 6: Write the final IUPAC name
Putting it all together, the correct IUPAC name for the compound is:
**3-methyl-1-hexene-5-yne**