Birch reduction: partial reduction of benzene ring (dissolving metal) (Benzene + Na (or Li) in liquid NH3 with alcohol → 1,4-cyclohexadiene (not fully saturated)
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Benzene + Na (or Li) in liquid NH3 with alcohol → 1,4-cyclohexadiene (not fully saturated cyclohexane).
What each symbol means
| Symbol | What it stands for |
|---|---|
| EtOH | Proton source to protonate radical anions / dianions |
| NH3(l) | Dissolving metal generates solvated electrons that reduce the ring |
When to use this
Dissolving-metal reduction. Substituted benzenes: electron-donating groups direct reduction to different positions than electron-withdrawing groups (JEE compares outcomes qualitatively).