Ester Hydrolysis and Saponification: Acid vs Base Mechanisms

Master ester hydrolysis under acidic and basic conditions. Learn saponification (irreversible), acid-catalyzed hydrolysis (reversible), and how to predict products and conditions on exams.

• Base hydrolysis: OH− attack → tetrahedral intermediate → RO− leaves → carboxylate (irreversible)
• Acid hydrolysis: Protonate carbonyl → H2O attack → ROH leaves → carboxylic acid (reversible)
• Key exam clue: Product under base is carboxylate unless acid workup is given
• Driving force (base): Carboxylate is stabilized and not electrophilic
• Exam type: Choose conditions
• Exam type: Predict the major product
• Exam type: Failure modes / distractors