Select the major product obtained from the addition of HBr to 1-methylcyclohexene.

Options

A. 1-bromo-2-methylcyclohexane
B. 6-bromo-1-methylcyclohex-I-ene
C. 3-bromo-1-methylcyclohex-1-ene
D. 1-bromo-1-methylcyclohexane

Answer

To determine the major product obtained from the addition of HBr to 1-methylcyclohexene, we can follow these steps:

### Step 1: Identify the Reactants
The reactant is 1-methylcyclohexene, which has a double bond in its structure. The addition reaction involves HBr, which is a polar molecule.

### Step 2: Understand the Mechanism of Addition
When HBr is added to an alkene, the double bond acts as a nucleophile and attacks the hydrogen (H) from HBr. This results in the formation of a carbocation intermediate.

### Step 3: Formation of the Carbocation
The double bond in 1-methylcyclohexene will preferentially bond with the hydrogen atom from HBr. Since the double bond is attached to a carbon that is also attached to a methyl group, the carbocation formed will be a tertiary carbocation (3°), which is more stable due to the electron-donating effect of the adjacent methyl group.

### Step 4: Nucleophilic Attack by Bromide Ion
After the formation of the carbocation, the bromide ion (Br-) from HBr will attack the positively charged carbon atom of the carbocation. This leads to the formation of the final product.

### Step 5: Determine the Major Product
The final product formed from this reaction is 1-bromo-1-methylcyclohexane. This compound has the bromine atom attached to the same carbon that was originally part of the double bond, which is now a single bond after the addition.

### Final Answer
The major product obtained from the addition of HBr to 1-methylcyclohexene is **1-bromo-1-methylcyclohexane**.

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