What product would be obtained from the reaction of cyclopropane with `Cl_(2)` in the presence of `FeCl_(3)`?

Options

A. 1,2-dichloropropane
B. 1,2-dichlorocyclopropane
C. 1,3-dichloropropane
D. 1,1-dichlropropane

Answer

To determine the product obtained from the reaction of cyclopropane with Cl₂ in the presence of FeCl₃, we can follow these steps:

### Step 1: Understand the Reactants
Cyclopropane (C₃H₆) is a three-membered carbon ring. It is known for having significant ring strain due to its small bond angles (approximately 60 degrees) compared to the ideal tetrahedral angle of 109.5 degrees in sp³ hybridized carbons.

### Step 2: Identify the Role of FeCl₃
FeCl₃ acts as a Lewis acid and helps generate a chlorine electrophile (Cl⁺) from Cl₂. The reaction can be represented as:
\[ \text{Cl}_2 + \text{FeCl}_3 \rightarrow \text{Cl}^+ + \text{FeCl}_4^- \]

### Step 3: Electrophilic Attack
The electrophilic chlorine (Cl⁺) will attack one of the carbons in the cyclopropane ring. Due to the ring strain, the cyclopropane is unstable, and the ring can open up upon attack by the electrophile.

### Step 4: Ring Opening
When Cl⁺ attacks cyclopropane, it leads to the opening of the ring, resulting in a linear chain of three carbon atoms:
\[ \text{C}_3\text{H}_6 \rightarrow \text{CH}_2^+ \text{CH}_2 \text{CH}_2 \]

### Step 5: Chlorination of the Open Chain
After the ring opens, the carbon chain can react further with another Cl atom from the Cl₂. The chlorine can attach to any of the terminal carbons of the now linear chain. The most stable product will have chlorine atoms on different carbons.

### Step 6: Determine the Product Structure
The final product will be 1,3-dichloropropane, where chlorine atoms are attached to the first and third carbon atoms of the propane chain:
\[ \text{ClCH}_2\text{CH}_2\text{CH}_2\text{Cl} \]

### Step 7: Write the IUPAC Name
The IUPAC name for the compound formed is 1,3-dichloropropane.

### Final Answer
The product obtained from the reaction of cyclopropane with Cl₂ in the presence of FeCl₃ is **1,3-dichloropropane**.

---