JEE PYQ: Hydrocarbons Question 23
Question 23 - 2020 (05 Sep Shift 2)
The major product formed in the following reaction is:
$\text{CH}_3\text{CH}=\text{CHCH}(\text{CH}_3)_2 \xrightarrow{\text{HBr}}$
(1) $\text{CH}_3\text{CH}(\text{Br})\text{CH}_2\text{CH}(\text{CH}_3)_2$
(2) $\text{CH}_3\text{CH}_2\text{CH}(\text{Br})\text{CH}(\text{CH}_3)_2$
(3) $\text{Br}(\text{CH}_2)_3\text{CH}(\text{CH}_3)_2$
(4) $\text{CH}_3\text{CH}_2\text{CH}_2\text{C}(\text{Br})(\text{CH}_3)_2$
Show Answer
Answer: (4)
Solution
$\text{CH}_3\text{CH}=\text{CHCH}(\text{CH}_3)_2 \xrightarrow{\text{H}^+}$ secondary carbocation $\xrightarrow{1,2\text{-H shift}}$ tertiary carbocation: $\text{CH}_3\text{CH}_2\text{CH}_2\overset{+}{\text{C}}(\text{CH}_3)_2$. $\text{Br}^-$ attacks to give $\text{CH}_3\text{CH}_2\text{CH}_2\text{C}(\text{Br})(\text{CH}_3)_2$.
BETA
