The major product formed during the hydroboration-oxidation of 1-methylcyclopentene is-

Options

A.
B.
C.
D.

Answer

To determine the major product formed during the hydroboration-oxidation of 1-methylcyclopentene, we can follow these steps:

### Step 1: Identify the Structure of 1-Methylcyclopentene
1-Methylcyclopentene is a cyclopentene ring with a methyl group attached to one of the carbon atoms in the ring. The structure can be represented as follows:

```
CH3
|
C=C
/ \
C C
\ /
C---C
```

### Step 2: Understand Hydroboration-Oxidation
The hydroboration-oxidation reaction involves two main steps:
1. **Hydroboration**: The alkene reacts with borane (BH3) or diborane (B2H6) in a solvent like tetrahydrofuran (THF). This step adds a boron atom (BH2) to the less substituted carbon atom of the alkene, following the anti-Markovnikov rule.
2. **Oxidation**: The boron atom is then replaced with a hydroxyl group (OH) using hydrogen peroxide (H2O2) in the presence of a base (like NaOH or KOH).

### Step 3: Apply the Anti-Markovnikov Rule
Since 1-methylcyclopentene is an unsymmetrical alkene, we apply the anti-Markovnikov rule:
- The more substituted carbon (the one attached to the methyl group) will receive a hydrogen atom (H).
- The less substituted carbon will receive the boron atom (BH2), which will later be converted to an OH group.

### Step 4: Determine the Product After Hydroboration
After hydroboration, the structure will look like this:

```
CH3
|
C-H
/ \
C B
\ /
C---C
```

Here, B represents the boron atom that will be converted to OH in the next step.

### Step 5: Perform the Oxidation Step
In the oxidation step, the boron (B) is replaced by a hydroxyl group (OH):

```
CH3
|
C-H
/ \
C OH
\ /
C---C
```

### Step 6: Identify the Final Product
The final product is 2-methylcyclopentanol, where the hydroxyl group is on the second carbon of the cyclopentane ring.

### Conclusion
The major product formed during the hydroboration-oxidation of 1-methylcyclopentene is **2-methylcyclopentanol**.