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Question #44411
The Question
Compound \textbf{X} is 1-(1-hydroxycyclobutyl)-1-phenylethan-1-ol. It undergoes two separate reactions: Reaction 1: \textbf{X} \textbf{P} (Major Product) Reaction 2: \textbf{X} \textbf{Q} + \textbf{R} Identify \textbf{P}, and the mixture of \textbf{Q} + \textbf{R}.
Options
- A.
\textbf{P} = 2-methyl-2-phenylcyclopentan-1-one ; \textbf{Q} + \textbf{R} = Cyclobutanone + Acetophenone
- B.
\textbf{P} = 1-(1-phenylcyclobutyl)ethan-1-one ; \textbf{Q} + \textbf{R} = Cyclobutanone + Acetophenone
- C.
\textbf{P} = 2-methyl-2-phenylcyclopentan-1-one ; \textbf{Q} + \textbf{R} = 5-oxo-5-phenylpentanal + Formaldehyde
- D.
\textbf{P} = 1-(1-methylcyclobutyl)phenylmethanone ; \textbf{Q} + \textbf{R} = Cyclopentanone + Benzaldehyde
Check Your Answer
Correct Answer
Step-by-Step Solution
Explanation
How the Examiner Thinks
Exception_Exposure
Learn to identify edge cases and boundary exceptions that JEE examiners hide in math problems.
Concepts Behind This Question
Pinacol-Pinacolone Rearrangement|Glycol Periodic Acid Cleavage
Why This Question Is Tricky
Common Mistakes
The problem tests the bifurcation of pathway choice in vicinal diols.
Students must recognize that triggers a Pinacol rearrangement governed by carbocation stability, whereas triggers oxidative cleavage governed by cyclic periodate formation.
The 'Trap' is failing to identify the more stable benzylic carbocation in Reaction 1, leading to incorrect migration (Option B), or misapplying the cleavage regioselectivity in Reaction 2.
The ring expansion of the strained cyclobutane ring provides a strong thermodynamic driving force, ensuring P is the cyclopentanone derivative.
Quick Facts About This Question
Question Information
| Subject | Chemistry |
| Chapter | Alcohols, Phenols, and Ethers - Class 12 |
| Concept | Pinacol-Pinacolone Rearrangement |
| Difficulty | 8 |
| Cognitive Load | 7 |
| Target Solve Time | 160 sec |
| Access | Free |