The Birch reduction uses sodium or lithium in solution as reagents, its mechanism is radical and reduces benzene to 1,4-cyclohexadiene.
Birch with activating substituents
The double bonds of the final cyclohexadiene lie close to the substituents that activate the ring.
![birch reduction 02](/images/stories/organica-i/benceno/birch/reduccion-birch-02.png)
Birch with deactivating substituents
The double bonds of the final cyclohexadiene lie away from the substituents that deactivate the ring.
![birch reduction 03](/images/stories/organica-i/benceno/birch/reduccion-birch-03.png)
Birch mechanism
Birch is a reaction that occurs with the formation of an anion-radical.
![birch reduction 04](/images/stories/organica-i/benceno/birch/reduccion-birch-04.png)