[w.uzar]

The reaction of anisole gives a 1-methoxycyclohexa-1,4-diene as a product of the birch reduction.

Could someone help me with the following issues and outline the reaction mechanisms?

1) Why does a 1-methoxycyclohexa-1,4-diene reaction with an acid that does not contain a nucleophilic anion give a 1-methoxycyclohexa-1,3-diene? What is the mechanism?

2) Why does a 1-methoxycyclohexa-1,4-diene reaction with an diluted acid give a cyclohex-3-en-1-one? What is the mechanism?

3) Why does a 1-methoxycyclohexa-1,4-diene reaction with an concentrated acid give a cyclohex-2-en-1-one? What is the mechanism?

Thank you very much for your answer!

[rolnor]

I give you a hint: Vinyl ether