Ring chain tautomerization of hydroxyacetone

My chemistry textbook says that hydroxypropane-2-one and 1,2-epoxy-2-hydroxypropane are ring chain tautomers, but it did not mention the steps for conversion of one into the other. I tried to figure them out but got stuck. 


My attempt:


[![tautomerisation](https://i.stack.imgur.com/DRpBg.jpg)](https://i.stack.imgur.com/DRpBg.jpg)




At first, even though this is not related to the question, I want to say that you're confused between double-headed arrow between the two resonance forms and double harpoon in reversible reactions. (The harpoons should be written as below.)


Your incomplete mechanism has two errors:


* The hydrogen atom bonded to carbon is far less reactive than the one bonded to oxygen.
* The positive carbon, which is bonded to oxygen, a very electronegative element, is very, very unstable, which is not likely to happen.


This is the right mechanism for the reaction:


[![enter image description here](https://i.stack.imgur.com/F6OH1.png)](https://i.stack.imgur.com/F6OH1.png)


Step 1: Oxygen is a good nucleophile, so it is most likely to take the most acidic hydrogen.  

Step 2: Then, the negative charged oxygen will attack the electrophile carbon atom, forming epoxy ring.


 7

Starting from the aldehyde, 


[![enter image description here](https://i.stack.imgur.com/qU9QX.png)](https://i.stack.imgur.com/qU9QX.png)


The double bond of the aldehyde breaks, allowing the oxygen to bond with the H in the alcohol. The alcohol subsequently breaks the O-H and forms a ketone. 


Note that this molecule is stabilised due to hydrogen bonding; therefore it may be prudent to add a base or acid to encourage tautomerization.


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