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JEE Advanced levelSingle correct optionDifficulty 3 of 3o2035

$(CH X_{3}) X_{3} C - CH = CH X_{2}$ reacts with HBr in the presence of peroxide. The major product is

A2-bromo-2,3-dimethylbutane
B1-bromo-2,3-dimethylbutane
C2-bromo-3,3-dimethylbutane
D1-bromo-3,3-dimethylbutane

Answer: D

The radical pathway has no carbocation, so no methyl shift.

Br \cdot

adds to the terminal carbon to give the secondary radical, which abstracts H from HBr. The product is

(CH X_{3}) X_{3} C - CH X_{2} - CH X_{2} Br

, 1-bromo-3,3-dimethylbutane. The other bromides come from the cationic route.

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