3 - methyl - 1 - butene on oxymercuration - demercuration yields . . . . . . As the major product

Options

A. 3-methyl-2-butanol
B. 2-methyl-r-butanol
C. 3-methyl-1-butanol
D. 2-methyl-1-butanol

Answer

To solve the problem of what major product is formed when 3-methyl-1-butene undergoes oxymercuration-demercuration (OMDM), we can break down the reaction into clear steps:

### Step-by-Step Solution:

1. **Identify the Structure of 3-Methyl-1-Butene**:
- 3-Methyl-1-butene is an alkene with the following structure:
```
CH2 = C(CH3) - CH2 - CH3
```
- The double bond is between the first and second carbon atoms, with a methyl group attached to the third carbon.

2. **Oxymercuration Step**:
- In the oxymercuration step, we use mercuric acetate (Hg(OAc)2) in the presence of water (H2O).
- The alkene reacts with mercuric acetate, leading to the formation of a mercurinium ion intermediate. The double bond attacks the mercury, leading to a cyclic structure where the mercury is positively charged and bonded to one of the carbons of the double bond.

3. **Formation of the Intermediate**:
- The mercurinium ion is formed, and water (acting as a nucleophile) attacks the more substituted carbon (the carbon with the methyl group) due to Markovnikov's rule. This results in the following intermediate:
```
CH3 - C(HgOAc) - CH2 - CH3
```

4. **Hydrolysis Step**:
- In the hydrolysis step, the mercurinium ion is converted to an alcohol. The acetate group (OAc) is replaced by a hydroxyl group (OH) when we perform demercuration, typically using sodium borohydride (NaBH4) or simply through hydrolysis.
- The final product after demercuration will be:
```
CH3 - C(OH) - CH2 - CH3
```
- This structure represents 3-methyl-2-butanol.

5. **Conclusion**:
- The major product formed from the oxymercuration-demercuration of 3-methyl-1-butene is **3-methyl-2-butanol**.

### Final Answer:
The major product formed from the oxymercuration-demercuration of 3-methyl-1-butene is **3-methyl-2-butanol**.

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