[kapital]

If we have compund with keton and ester functional group(like for example ethyl acetoacetate) and nucleophil, does nucleophilic attack always hapend at keton place? Whic carbon in more electronegative?(ketone or ester)

[ajolly]

First of all, I would never say the word “always” when dealing with chemistry because that word assumes that there are no exceptions and in science generally there are always exceptions.  In addition, the carbon that would carry the higher affinity for electrons would be the ester as it carries the leaving group OCH2CH3.  This leaving group (OCH2CH3) it is able to leave under certain conditions, however relative to most other leaving groups it is not that great.  Also a nice rule of thumb acyl halides carry better leaving groups then anhydrides which carry better leaving groups then carboxylic acids which carry better leaving groups then esters.  So in general acyl-group reactivities with nucleophiles are as follows: acyl-halide>Anhydride>carboxilic acids>esters>amides>ketones>aldehydes.  Hope this helps!

[kapital]

Yes, that is probably part of the answer. 

So if this compund would react with ammonia

we get this

and not this:

??

[rrr]

Probably we get a mixture of both products.
In general, ketone group is more preferable than ester one, but ester can react with ammonia too.

[discodermolide]

The Imine could also produce the enamine.


Gives a nice conjugated system.

[kapital]

Well, that are probalby the same compund, just different resonance structures?