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Question #45054
The Question
Consider the intramolecular Aldol condensation of 1,1,1-trifluoro-2,8-nonanedione. The reaction is carried out in an excess of aqueous at 298 K for an extended period, followed by heating to yield the major thermodynamic product . Identify the IUPAC name of .
Options
- A.
1-(2-methylcyclohex-1-en-1-yl)-2,2,2-trifluoroethan-1-one
- B.
1-(2-(trifluoromethyl)cyclohex-1-en-1-yl)ethan-1-one
- C.
1-(3-methylcyclohex-1-en-1-yl)-2,2,2-trifluoroethan-1-one
- D.
1-(3-(trifluoromethyl)cyclohex-1-en-1-yl)ethan-1-one
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
Resonance Energy and Stability|Aldol Condensation Directionality|Hydrate Stability vs. Carbonyl
Why This Question Is Tricky
Common Mistakes
This question tests the 'Hydrate Masking Exception' in Aldol condensations.
Students typically rely on rote electronic effects, identifying the trifluoromethyl ketone as the superior electrophile due to the -I effect of CF3.
The hidden variable is the solvent environment: in aqueous base, highly electrophilic carbonyls form stable hydrate anions (gem-diolates).
This masks the expected electrophilic center, forcing the molecule to utilize a kinetically less favored enolate to attack the unmasked, less electrophilic carbonyl, completely inverting the expected regioselectivity of the intramolecular ring closure.
Quick Facts About This Question
Question Information
| Subject | Chemistry |
| Chapter | Organic Chemistry – Some Basic Principles and Techniques - Class 11 Part 2 |
| Concept | Resonance Energy and Stability |
| Difficulty | 8 |
| Cognitive Load | 7 |
| Target Solve Time | 160 sec |
| Access | Free |