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Question #44641
The Question
Consider the reaction of 2-bromo-1,3-di-tert-butylbenzene with an equimolar amount of bromoethane in the presence of excess sodium metal in dry ether at 298 K. Which of the following represents the major organic products formed?
Options
- A.
2-ethyl-1,3-di-tert-butylbenzene
- B.
1,3-di-tert-butylbenzene, butane, ethane, and ethene
- C.
2,2',6,6'-tetra-tert-butylbiphenyl and butane
- D.
1-(2-bromoethyl)-2,4-di-tert-butylbenzene
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
Wurtz and Wurtz-Fittig Coupling|Steric Hindrance in SN2|Coupling Reactivity
Why This Question Is Tricky
Common Mistakes
Students often blindly apply the Wurtz-Fittig reaction to any aryl and alkyl halide combination, expecting a cross-coupled product.
The hidden variable here is the steric requirement of the transition state during the coupling step.
When bulky groups (like tert-butyl) occupy the ortho positions of the aryl halide, they create a 'steric shield' that completely blocks the approach of the alkyl halide.
Consequently, the kinetically favored cross-coupling fails, and the system defaults to radical disproportionation, homocoupling of the unhindered alkyl halide, and reduction of the aryl halide.
Quick Facts About This Question
Question Information
| Subject | Chemistry |
| Chapter | Haloalkanes and Haloarenes - Class 12 |
| Concept | Wurtz and Wurtz-Fittig Coupling |
| Difficulty | 8 |
| Cognitive Load | 7 |
| Target Solve Time | 160 sec |
| Access | Free |