Discussion in 'MCAT Study Question Q&A' started by TawMus, 05.21.08.
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What is the order of stability??
Ketone, aldehyde, enol??
i'm no o chem expert...but i believe enol is the least stable (keto-enol tautomerism comes to mind) followed by aldehyde and then ketone.
I will assume ketones are most stable because it has two R groups which are EDGs and will supply the partially positive carbonyl carbon with electrons. Therefore I assume:
Ketone > Aldehyde > Enol
Also Aldehydes are more reactive in nucleophilic additions because of the less steric hindrance
The reason why aldehydes are more reactive for nucleophillic additions is because ketones have 2 alkyl groups while aldehydes only have. Sterics play a minor role, however. The reason why aldehydes are more reactive is because there is more positive charge on the carbonyl carbon. Ketones, with 2 electron donating groups, have less positive charge on the carbonyl carbon, and are thus less reactive to nucleophillic attack at the carbonyl carbon. Keep in mind that carbonyls are sp2 hybridized and thus planar making sterics less of an issue.
true. that's close to what i was trying to say with my first point.
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