Question

Question: Treatment of 3-methylcyclohexene with HCl yields two products, 1-chloro-3-methylcyclohexane and 1-chloro-1-methylcyclohexane. Draw a mechanism to explain this result.

Short answer

Answer

Mechanism

Step-by-step solution

Markovnikov rule

The carbon atom with a higher number of hydrogen atoms in the $\mathit{C}\mathbf{=}\mathit{C}$ bond gets the hydrogen atom from HX bonded to it.

Carbocation stability

The more substituted and stable carbocation is favored to form the major product. However, the products also contain some amount of that product that has resulted from a less substituted carbocation.

Products of the given reactions

The addition of the hydrogen atom from HX to 3-methylcyclohexene leads to two $2°$carbocations. In one case, the carbocationic center is next to the carbon having a methyl group.

Hence, the carbocation undergoes a 1,2-H shift to form a $3°$ carbocation, leading to the formation of two products.

Mechanism