Identify the major product formed when $\text{3,3-dimethylbut-1-ene}$ reacts with $\text{HBr}$ in the presence of a peroxide.

Solution

1. The reaction of $\text{HBr}$ with alkenes in the presence of peroxides follows a free radical mechanism.
2. The bromine radical adds to the terminal carbon to form the more stable tertiary radical intermediate.
3. The tertiary radical abstracts a hydrogen atom from $\text{HBr}$ to yield the anti-Markovnikov product.
4. The product is $\text{1-bromo-3,3-dimethylbutane}$.
5. Hence the answer is (A).