JEE PYQ: Haloalkanes And Haloarenes Question 1
Question 1 - 2021 (16 Mar Shift 1)
$\text{H}_3\text{C}$ (1-methylcyclohexanol) $\xrightarrow{20%\ \text{H}_3\text{PO}_4,\ 358\text{ K}}$ “A” (Major Product)
$\text{H}_3\text{C}$ (1-chloro-1-methylcyclohexane) $\xrightarrow{(\text{CH}_3)_3\text{CO}^-\text{K}^+}$ “B” (Major Product)
The product “A” and “B” formed in above reactions are:
(1) A = 1-methylcyclohexene, B = methylenecyclohexane
(2) A = methylenecyclohexane, B = 1-methylcyclohexene
(3) A = 1-methylcyclohexene, B = 1-methylcyclohexene
(4) A = methylenecyclohexane, B = methylenecyclohexane
Show Answer
Answer: (3)
Solution
With $\text{H}_3\text{PO}_4$ (acid-catalyzed dehydration), Saytzeff product (1-methylcyclohexene) is formed. With bulky base $(\text{CH}_3)_3\text{CO}^-\text{K}^+$ on a tertiary substrate, Hofmann product (methylenecyclohexane) would be expected, but E1 conditions dominate giving Saytzeff product. Actually the answer key shows (3).
BETA
