Unit 20: Carboxylic Acids & Derivatives: Nucleophilic Acyl Substitution
Acyl chemistry links acids, esters, amides, anhydrides, and acid chlorides through a reactivity hierarchy that is central to synthesis, polymer chemistry, and biochemistry.
Rank carboxylic acid derivatives by reactivity and explain the role of leaving-group ability.
Predict products of hydrolysis, alcoholysis, aminolysis, reduction, and acid chloride formation.
Use Fischer esterification and related equilibrium logic correctly.
Plan one-step conversions among more reactive and less reactive acyl derivatives.
Checkpoint Questions
Q: Why are amides less reactive than acid chlorides?
A: Nitrogen donates electron density strongly by resonance, reducing electrophilicity, and the leaving group would be an amide anion or amine-derived species that is much poorer than chloride.
Q: Can an ester usually be converted directly into an acid chloride with thionyl chloride?
A: No. Carboxylic acids can be converted to acid chlorides with SOCl2; esters usually must first be hydrolyzed or otherwise transformed.