I came across this ques. in many books and i'm not satisfied with the answer given. Plz help.
Q. Maximum enolisation will take place in :
a) CH3COCH3
b) CH3COCH2CHO
c) CH3COCH2COCH3
d) Cyclohexa-2,4-dien-1-one
The answer i thought was c) as it has to keto groups and so will be able to maximise enol form. But the answer given is d) in which acc. to me enol will be highly unstable due to formation of cumulated diene.
Plz give the correct explanation.
Hai!
It is associated with aromatic stability.i.e.it has benzene nucleus.
Can you please explain your argument. I didn't got it completely.
It doesn't form cumulated diene because in that case the alpha hydrogen is already attached to unsaturated carbon.Instead it forms enol with the other alpha hydrogen which is attached to an sp3 carbon and hence it results in aromatic stability.This can be explained using quinone.Quinone doesnt have enol form as all the alpha hydrogen are attached to sp2 carbon.
Thnx a lot for the explanation.