[smghz]

I've been trying to know why, for example, the enol of cyclohexanone is not favored, when the enol of 1,3-cyclohexanedione is favored. Isn't the alpha hydrogen in both cases getting acidified? My professor said that for the latter, "positioning the second carbonyl in a 1,3 relationship with the other carbonyl greatly acidifies the proton on the central carbon". But I don't understand that statement very well, and don't see how it's unique only to 1,3-cyclohexanedione.

[Babcock_Hall]

It seems to me that you are asking two separate (although not entirely unrelated questions).  One, what governs the equilibrium in ketone-enol tautomerizations.  Two, why are 1,3-dicarbonyls more acidic than say 1,4 dicarbonyls.  The second question involves the potential loss of a proton and is governed by the pK_a, but the first question does not imply the loss of a proton.  Is that correct?

[smghz]

Exactly, I mean, I see an enol formed in both cases with the loss of one proton. Why does the flanking of the alpha hydrogen by two carbonyl groups make it that much more likely for an enol to form, relative to a molecule that has only a single carbonyl group?