Complete the following reactions
`CH_(3)CH=CH_(2)overset(mCPBA)rarr A overset(C_(2)H_(5)MgBr)underset(H_(3)O^(+))rarr B`

Answer

To solve the given reaction sequence, we will break it down into two main steps: the reaction with mCPBA and the reaction with C2H5MgBr followed by H3O+.

### Step 1: Reaction with mCPBA

1. **Starting Material**: The starting material is propene (CH3CH=CH2).
2. **Reagent**: The reagent used is mCPBA (meta-Chloroperoxybenzoic acid), which is a peracid.
3. **Mechanism**: The mCPBA will perform an epoxidation reaction on the double bond of propene. The oxygen from mCPBA will add to the double bond, forming an epoxide.
4. **Product Formation**: The product formed (A) will be an epoxide, specifically propylene oxide (C3H6O), which has the structure:
- CH3-CH(O)-CH2 (where O is part of the epoxide ring).

### Step 2: Reaction with C2H5MgBr and H3O+

1. **Reagent**: The next reagent is C2H5MgBr, which is an organomagnesium compound (Grignard reagent).
2. **Nucleophilic Attack**: The Grignard reagent will attack the less hindered carbon of the epoxide ring. This is due to the ring strain and the electrophilic nature of the epoxide.
3. **Intermediate Formation**: This will lead to the opening of the epoxide ring and the formation of an alcohol intermediate. The structure will be:
- CH3-CH(CH2C2H5)-OH (where the ethyl group from C2H5MgBr has added to the carbon that was part of the epoxide).
4. **Protonation**: Upon treatment with H3O+, the alkoxide (–O^-) will be protonated to form the final alcohol product (B).
5. **Final Product**: The final product (B) will be:
- CH3-CH(CH2C2H5)-OH.

### Summary of Products
- **Product A**: Propylene oxide (C3H6O).
- **Product B**: 1-ethyl-2-propanol (C5H12O).

### Final Answer
- A = Propylene oxide (C3H6O)
- B = 1-ethyl-2-propanol (C5H12O)

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