Aldehydes and Ketones
4.0 Relative Reactivities of Carbonyl Compounds
4.1 Relative Reactivities towards Nucleophilic addition
4.2 Rate of Nucleophilic Substitution
4.3 Reactivitiy Considerations
4.0 Relative Reactivities of Carbonyl Compounds
4.2 Rate of Nucleophilic Substitution
4.3 Reactivitiy Considerations
As we know that the carbonyl group is polar, since oxygen being more electronegative than carbon, has a greater share of electrons of the double bond. Because of the partial positive charge of the carbonyl carbon, carbonyl compounds are attacked by nucleophiles.
Aldehydes are more reactive towards nucleophilic attack than are ketones. Because alkyl groups are electron donating compared to a hydrogen, an aldehyde has a greater partial positive charge on its carbonyl carbon, making it more susceptible to attack by a nucleophile.
Since steric factor also contribute to the greater reactivity of the aldehyde compared with a ketone. Because, the hydrogen attached to the acyl group of an aldehyde group is smaller than the alkyl group attached to the acyl group of a ketone, the carbonyl carbon of an aldehyde is more accessible to the nucleophile than is the carbonyl carbon of a ketone. For the same reason, ketones with small alkyl groups bonded to the carbonyl carbon are more reactive than ketone with large alkyl groups.
