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Question #43965
The Question
Consider the intramolecular Aldol condensation of 7,7-dimethyl-6-oxooctanal in the presence of dilute aqueous at . Identify the major organic product formed.
Options
- A.
1-(cyclopent-1-en-1-yl)-2,2-dimethylpropan-1-one
- B.
2-(tert-butyl)cyclopent-1-ene-1-carbaldehyde
- C.
3-(tert-butyl)cyclopent-1-ene-1-carbaldehyde
- D.
1-(cyclopent-2-en-1-yl)-2,2-dimethylpropan-1-one
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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
Aldol Condensation Directionality|Nucleophilic Addition Sterics|Alpha-Hydrogen Acidity
Why This Question Is Tricky
Common Mistakes
This problem tests the Curtin-Hammett principle and the competition between thermodynamic acidity and kinetic nucleophilic attack in an intramolecular Aldol condensation.
Students typically fall into the trap of assuming the most acidic -hydrogen (at C2) dictates the reaction, leading them to predict 2-(tert-butyl)cyclopent-1-ene-1-carbaldehyde.
The 'Hidden Variable' is the extreme steric hindrance of the \textit{tert}-butyl group at the C6 electrophilic site, which drastically suppresses the rate of attack.
The reaction is instead funneled through the less stable C5 enolate because its attack on the unhindered C1 aldehyde has a much lower transition state energy.
Quick Facts About This Question
Question Information
| Subject | Chemistry |
| Chapter | Aldehydes, Ketones, and Carboxylic Acids - Class 12 |
| Concept | Aldol Condensation Directionality |
| Difficulty | 8 |
| Cognitive Load | 7 |
| Target Solve Time | 160 sec |
| Access | Free |