What is obtained, when propene is treated with N-bromo succinimide `:`

Options

A. `CH_(3) - underset( Br) underset( |) ( C ) = CH_(2)`
B. `BrCH_(2) - CH = CH_(2)`
C. `BrCH_(2) -CH = CHBr`
D. `BrCH_(2) - underset( Br) underset( |)( C ) H -CH_(2) Br`

Answer

To find out what product is obtained when propene is treated with N-bromo succinimide (NBS), we can follow these steps:

### Step-by-Step Solution:

1. **Identify the Reactants**:
- The reactant is propene, which has the molecular structure CH2=CH-CH3.
- N-bromo succinimide (NBS) is a reagent used for allylic bromination.

2. **Understand the Reaction Type**:
- The reaction involves allylic bromination, which occurs at the allylic position (the carbon adjacent to the double bond) of propene.
- NBS facilitates this reaction through a free radical mechanism.

3. **Draw the Structure of Propene**:
- Propene can be represented as:
```
H H
| |
H-C=C-H
| |
H H
```

4. **Identify the Allylic Position**:
- In propene, the allylic carbon is the one next to the double bond. For propene, the allylic carbon is the one connected to the CH3 group.

5. **Mechanism of Reaction**:
- The reaction proceeds via a free radical mechanism:
- **Initiation**: NBS generates bromine radicals.
- **Propagation**: The bromine radical abstracts a hydrogen atom from the allylic position, forming an allylic radical.
- **Termination**: The allylic radical reacts with another bromine radical to form the final product.

6. **Formation of the Product**:
- The allylic radical formed will be:
```
H Br
| |
H-C-C-H
| |
H H
```
- The final product after bromination will be 3-bromopropene, which can be represented as:
```
H Br
| |
H-C=C-H
| |
H H
```

7. **Final Product**:
- The product obtained from the reaction of propene with N-bromo succinimide is **3-bromopropene**.