Which carbon is most likely to form...

[sfoksn]

Carbanion?

Carbonyl carbon vs. alpha carbon?

I would think alpha carbon, but one of my problem's answer says it is the carbonyl carbon.

Thank you.

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[azar87]

the carbonyl can form an anion because the double bond can break an the oxygen can have a negative charge on it.

 

[sfoksn]

are you saying carbonyl carbon is more likely to form carbanion than the alpha carbon?

 

[Slack3r]

the carbonyl can form an anion because the double bond can break an the oxygen can have a negative charge on it.

So you're going to have a negative oxygen bound to a negative carbon?

 

[sfoksn]

i think azar misunderstood the question, b/c the carbonyl carbon, as far as my limited knowledge goes, is electrophillic and is often attacked by nucleophiles.

therefore i dont think it is a suitable candidate to form carbANION... its already lacking electrons due to oxygen right next to it...

so can anyone give us a definite answer?

 

[RSD2014]

Carbanion?

Carbonyl carbon vs. alpha carbon?

I would think alpha carbon, but one of my problem's answer says it is the carbonyl carbon.

Thank you.

Alpha Carbon would be better at forming Carbanion.
You can see it in reactions like Aldol condensation, Claisen Ester condensation and acetoacetic ester synthesis reactions. Alpha carbon is depronated to form carbanion and that attacks the Carbonyl of a second molecule to form the product. Carbonyl is usually being attacked so I assume it has a partial positive charge on the carbon. Oxygen is pulling e- away from the carbon of the carbonyl, causing it to become more positive.

That's my understanding, feel free to correct me.