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Chemistry Forums for Students => Organic Chemistry Forum => Topic started by: Allendo on May 06, 2020, 01:13:20 AM

Title: Acetoacetic Ester Synthesis, base catalyzed
Post by: Allendo on May 06, 2020, 01:13:20 AM

Hi all
For Acetoacetic Ester Synthesis,

http://www.chem.ucalgary.ca/courses/351/Carey5th/Ch21/ch21-5-1.html

in the 3rd step (which is the 2nd step if you look at the btm pic), if I add base to transform the ester to a carboxylate, I understand the mechanism by itself (-OH add to the ester's carbonyl carbon and kick off the -OR group, which fast deprotonate the carboxylic acid to carboxylate.).

But my question is that why don't the -OH attack the ketone carbonyl carbon as well, which is more reactive than the ester carbonyl carbon. In my opinion, the ester side will be transformed into a carboxylate and the ketone side will be transformed into a diol after protonation.

Title: Re: Acetoacetic Ester Synthesis, base catalyzed
Post by: rolnor on May 06, 2020, 02:53:23 AM

Do you mean a diol with twoo hydroxylgroups on the same carbon? These are generally not stable.

Title: Re: Acetoacetic Ester Synthesis, base catalyzed
Post by: Allendo on May 06, 2020, 04:30:53 AM

You are absolutely correct! Thanks!