How do you know when to do a tautomeric shift?

[JMC117]

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For example, if I have this: CH3-COH=CH2

How do I know that it's supposed actually be this after tautomeric shift:

CH3-C=O-CH3

Sorry if it's hard to understand

 

[sleepinxlionhar]

THe first compound you have is an enol, and it is more stable in a keto form, which is the 2nd compound you wrote down. Generally, tautomerization occurs when you have an OH group next to a double bond(basically a enol). But remember, it only happens when there's a double bond next to it, tautomerization can never occur with a single or triple bond.

 

[JMC117]

Thanks so much! I understand now. Thanks for your time and help 🙂