The major product of the following reaction is :
`(CH_3)_2C=CH-CH_2-CH_3overset((i)B_2H_6,"ether"(ii)H_2O_2, "NaOH")to`

Options

A.
B.
C.
D.

Answer

To determine the major product of the reaction involving `(CH_3)_2C=CH-CH_2-CH_3` with diborane (B2H6) followed by hydrogen peroxide (H2O2) and sodium hydroxide (NaOH), we will follow the hydroboration-oxidation mechanism. Here’s a step-by-step breakdown of the process:

### Step 1: Hydroboration
1. **Reaction with Diborane (B2H6)**:
- The alkene `(CH_3)_2C=CH-CH_2-CH_3` reacts with diborane.
- In this step, diborane (B2H6) breaks down into boron hydride (BH3), which adds across the double bond of the alkene.
- The addition occurs in a syn manner, meaning both the hydrogen (H) and boron (B) add to the same side of the double bond.

### Step 2: Identify the Anti-Markovnikov Addition
2. **Anti-Markovnikov Rule**:
- According to the anti-Markovnikov rule, the hydrogen atom will add to the less substituted carbon atom of the double bond, while the boron atom will add to the more substituted carbon.
- In our case, the double bond is between the second and third carbon atoms. Therefore, the hydrogen will add to the second carbon (less substituted), and the boron will add to the third carbon (more substituted).

### Step 3: Formation of Organoborane
3. **Formation of Organoborane**:
- The product of this step will be `(CH_3)2C-CH(BH2)-CH2-CH3`, where BH2 is attached to the more substituted carbon.

### Step 4: Oxidation with Hydrogen Peroxide and Sodium Hydroxide
4. **Oxidation Step**:
- The organoborane is then treated with hydrogen peroxide (H2O2) in the presence of sodium hydroxide (NaOH).
- During this oxidation step, the boron atom is replaced by a hydroxyl group (OH) through a process known as hydrolysis.
- The OH group will replace the BH2 group, resulting in the formation of an alcohol.

### Step 5: Final Product
5. **Final Product**:
- The final product after the oxidation will be `(CH_3)2C-CH(OH)-CH2-CH3`, which is 2-pentanol.
- The structure can be represented as:
```
CH3
|
CH3-C-CH2-CH3
|
OH
```

### Conclusion
The major product of the reaction is **2-pentanol** (or **sec-pentanol**).