# Tautomerism between cyclohex-2-en-1-one and cyclohex-3-en-1-one

I think cyclohex-2-en-1-one and cyclohex-3-en-1-one should undergo tautomerism as shown below:

I'm calling it tautomerism because of it's similarity with the tautomerism mechanism in basic medium. I can't draw reaction mechanism arrows using the software I'm using, but what I've shown is that the base abstracts the hydrogen at the alpha-position of the carbonyl group in the first step to form a carbanion, which has multiple resonance structures. The structure I have shown can abstract a proton from water to form cyclohex-2-en-1-one, which I believe should be the predominant form among the two (and among the enol forms as well).

Is this correct? I've never seen anything similar before so I'm a bit skeptical. A similar mechanism can be shown in acidic medium.

As an example, it would be expected that 4-chlorocyclohexanone on reaction with alc. $$\ce{KOH}$$ and heating would undergo E2 to give cyclohex-3-en-1-one. Assuming that alc. $$\ce{KOH}$$ is present in excess, if what I've shown above is correct then cyclohex-3-en-1-one will further undergo tautomerism to give cyclohex-2-en-1-one as the major product.

• Well, yes, you're right, but then again what answer you expect? "Am I right" questions are very troublesome when OP is right... Jul 28 '21 at 15:53
• @Mithoron ahh well.. if what I've shown is right, I don't think there is much scope to answer. I think I'll still leave the question because I couldn't find anything online or in the books I have similar to this. Nevertheless, thank you for the confirmation. Jul 28 '21 at 16:23
• Add some follow up question, or maybe someone is just gonna elaborate on that. BTW what you say say about not finding stuff, only says about your searching. This is pretty elementary thing and I'm pretty sure was asked already on this site. Jul 28 '21 at 16:53
• Jul 28 '21 at 16:59