Iso - butylene when subjected to hydroboration oxidation reaction yields

Options

A. Sec-butyl alcohol
B. Tert-butyl alcohol
C. Iso-butyl alcohol
D. n-butyl alcohol

Answer

To solve the question regarding the hydroboration-oxidation of isobutylene, we will follow these steps:

### Step-by-Step Solution:

1. **Identify the Structure of Isobutylene**:
Isobutylene (also known as 2-methylpropene) has the molecular formula C4H8. Its structure can be represented as:
\[ \text{CH}_2=C(\text{CH}_3)\text{CH}_3 \]

2. **Understand Hydroboration Reaction**:
Hydroboration involves the addition of borane (BH3) to the alkene. In this case, the double bond in isobutylene will react with BH3. The boron atom will bond to the less substituted carbon atom due to steric hindrance.

3. **Formation of Organoborane Intermediate**:
When BH3 adds to isobutylene, it forms an organoborane intermediate. The reaction can be depicted as:
\[ \text{CH}_2=CH(\text{CH}_3) + \text{BH}_3 \rightarrow \text{CH}_3\text{CH}_2\text{B}(\text{H})_2 \]
Here, the boron atom is attached to the carbon that was less substituted.

4. **Oxidation Step**:
The next step is oxidation, which typically involves the use of hydrogen peroxide (H2O2) in a basic medium. This converts the organoborane intermediate into an alcohol.
\[ \text{CH}_3\text{CH}_2\text{B}(\text{H})_2 + \text{H}_2\text{O}_2 \rightarrow \text{CH}_3\text{CH}_2\text{OH} + \text{B(OH)}_3 \]

5. **Identify the Product**:
The product formed from this reaction is 2-butanol (also known as secondary butyl alcohol), which has the structure:
\[ \text{CH}_3\text{CH(OH)}\text{CH}_2\text{CH}_3 \]

### Final Answer:
The hydroboration-oxidation of isobutylene yields **2-butanol (secondary butyl alcohol)**.