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Question #44380
The Question
Consider the reaction of 2-hydroxy-5-methyl-1-phenylhex-5-en-1-one with mercuric acetate in aqueous THF, followed by reduction with sodium borohydride in aqueous sodium hydroxide at .
Identify the major product (P).
Options
- A.
(5,5-dimethyltetrahydrofuran-2-yl)(phenyl)methanone
- B.
2,5-dihydroxy-5-methyl-1-phenylhexan-1-one
- C.
(5,5-dimethyltetrahydrofuran-2-yl)(phenyl)methanol
- D.
(5-methyltetrahydro-2H-pyran-2-yl)(phenyl)methanone
Check Your Answer
Correct Answer
Step-by-Step Solution
Explanation
How the Examiner Thinks
Mechanism_Trap
Don't get tricked by the process! Learn the mechanical traps used in competitive exam questions.
Concepts Behind This Question
Oxymercuration-Demercuration Specificity|Reduction Selectivity (Hydrides)
Why This Question Is Tricky
Common Mistakes
This problem tests the 'Chemoselectivity Hierarchy' and 'Neighboring Group Participation'.
The primary trap is the assumption that NaBH4 acts as a universal carbonyl reducer.
In the specific context of Oxymercuration-Demercuration, the reduction of the organomercurial intermediate is a kinetically rapid radical process that outpaces the ionic reduction of the ketone.
Additionally, it tests the student's ability to recognize that an internal nucleophile (hydroxyl) will outcompete the solvent (water) to form a stable 5-membered ring via Markovnikov (5-exo-trig) closure, rather than yielding the acyclic diol or the anti-Markovnikov 6-membered ring.
Quick Facts About This Question
Question Information
| Subject | Chemistry |
| Chapter | Alcohols, Phenols, and Ethers - Class 12 |
| Concept | Oxymercuration-Demercuration Specificity |
| Difficulty | 8 |
| Cognitive Load | 7 |
| Target Solve Time | 160 sec |
| Access | Free |