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Question #44372
The Question
Consider the enantiomerically pure compound \textbf{X}, -5-bromo-4-methylpent-1-ene. Compound \textbf{X} is subjected to the following reaction sequence:
- , followed by
- turnings, dry ether
- , followed by acidic workup ()
Identify the major organic product \textbf{Y} and its stereochemical nature.
Options
- A.
6-hydroxy-3-methylhexanoic acid; Optically active
- B.
4-methylpentan-1-ol; Optically inactive
- C.
4-methylpentan-2-ol; Optically active
- D.
5-hydroxy-3-methylhexanoic acid; Optically active
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
Hydroboration-Oxidation Regiochemistry|Grignard Reaction Pathways|Grignard Reagent Sensitivity
Why This Question Is Tricky
Common Mistakes
This problem tests the 'Functional Group Incompatibility' exception in Grignard synthesis, combined with a hidden stereochemical trap.
Students often blindly execute the reaction sequence, assuming the Grignard reagent will react with the provided electrophile (CO2) to form a carboxylic acid (Option A).
However, they overlook the internal 'Lethal Collision': the extreme basicity of the Grignard carbon instantly quenches against the unprotected -OH group formed in the first step.
Furthermore, the problem tests spatial reasoning; the acid-base quench converts a -CH2MgBr group into a -CH3 group, which happens to be identical to the existing methyl branch, resulting in an unexpected loss of chirality.
Quick Facts About This Question
Question Information
| Subject | Chemistry |
| Chapter | Alcohols, Phenols, and Ethers - Class 12 |
| Concept | Hydroboration-Oxidation Regiochemistry |
| Difficulty | 8 |
| Cognitive Load | 7 |
| Target Solve Time | 160 sec |
| Access | Free |