Nucleophilic addition involves the addition of a nucleophile to an aldehyde or a ketone. The nucleophile adds to the electrophilic carbonyl carbon.
Charged nucleophiles undergo nucleophilic addition with an aldehyde or ketone to give a charged intermediate which has to be treated with acid to give the final product. Neutral nucleophiles require acid catalysis and fur- ther reactions can take place after nucleophilic addition.
As the name of the reaction suggests, nucleophilic addition involves the addition of a nucleophile to a molecule. This is a distinctive reaction for ketones and aldehydes and the nucleophile will add to the electrophilic carbon atom of the carbonyl group.
The nucleophile can be a negatively charged ion such as cyanide or hydride, or it can be a neutral molecule such as water or alcohol.
In general, addition of charged nucleophiles results in the formation of a charged intermediate (Fig. 1). The reaction stops at this stage and acid has to be added tocomplete the reaction.
Neutral nucleophiles where nitrogen or oxygen is the nucleophilic center are relatively weak nucleophiles, and an acid catalyst is usually required. After nucleophilic addition has occurred, further reactions may take place leading to structures such as imines, enamines, acetals, and ketals.