Birch Reduction
Hardchemistry
Birch reduction of benzene yields:
Select the correct option:
Solution
Incorrect! Answer:
1,4-Cyclohexadiene
- Reactants: Sodium (Na) or Lithium metal in liquid Ammonia (NH3) with an alcohol (proton source).
- Mechanism: Electron transfer from the alkali metal to the benzene π-system followed by protonation.
- Result: Benzene is partially reduced to a non-conjugated diene.
- Regiochemistry: The hydrogens add at the 1 and 4 positions to minimize electron-electron repulsion during the intermediate radical-anion phase.
- Product: 1,4-Cyclohexadiene.
- Note: This is different from catalytic hydrogenation (H2/Ni), which would give the fully saturated Cyclohexane.
🔒 Solution Hidden from View
Submit your answer to unlock the detailed step-by-step solution.
About This Question
- Subject
- chemistry
- Chapter
- hydrocarbons
- Topic
- birch reduction
- Difficulty
- Hard
- Year
- 2025
Solution
Correct Answer:
1,4-Cyclohexadiene
- Reactants: Sodium (Na) or Lithium metal in liquid Ammonia (NH3) with an alcohol (proton source).
- Mechanism: Electron transfer from the alkali metal to the benzene π-system followed by protonation.
- Result: Benzene is partially reduced to a non-conjugated diene.
- Regiochemistry: The hydrogens add at the 1 and 4 positions to minimize electron-electron repulsion during the intermediate radical-anion phase.
- Product: 1,4-Cyclohexadiene.
- Note: This is different from catalytic hydrogenation (H2/Ni), which would give the fully saturated Cyclohexane.
This hard difficulty chemistry question is from the chapter hydrocarbons, covering the topic of birch reduction. It appeared in the 2025 exam.
Looking for more practice? Explore all chemistry questions or browse hydrocarbons questions on RankGuru.