Reactions at the carbonyl group

• Nucleophilic attack
  • Nucleophilic attack leading to nucleophilic substitution is a two part process whereby (1) nucleophilic addition and (2) elimination occurs. This latter step causes the $C=O$ to re-form:
    

    Figure 50.9: Nucleophilic attack and elimination at the carboxylic acid carbonyl.

    

• Reduction
  • Reduction of carboxylic acids by a reducing agent, e.g. LAH, produces an aldehyde. Further reduction produces an alcohol:
    

    Figure 50.10: Reduction of carboxylic acids with LAH.

    

• Decarboxylation
  • Reaction in which a carboxylic acid loses CO$_{2}$. This is a slow reaction that requires a significant amount of heat.
    

• Fischer esterification
  • The synthesis of esters by the reaction of a carboxylic acid with an alcohol:
    

    Figure 50.11: Fischer esterification.