1. Lecture 33 – Chapter 20 : Ester Hydrolysis
Ester hydrolysis – acid catalyzed
Ester hydrolysis – base catalyzed (saponification)
Lecture 33 – Chapter 21 : Ester Enolates
Ester enolate formation – a-deprotonation
Ester enolate reacting with ester – Claisen condensation

2. Carboxylic Acid Esters
Tetronolide derivative – beetle sex attractant
Fatty acid Ester (triglyceride)

3. Carboxylic Acid Esters – hydrolysis
Acid-catalyzed hydrolysis
Basic hydrolysis – saponification

5. Fatty acid biosynthesis
carbon chain extended by 2, can go up to C16, C18, C20 iteratively

6. Chapter 21: Deprotonation of a-H in Esters
Choice of base is important
Saponification competes with deprotonation when hydroxide used
Last step of saponification is irreversible, leads to carboxylate salt
Use the base that corresponds to the OR’ group on the ester

7. Claisen: Same setup as the simple aldol reaction
Both enolate and ester present in mixture:
Claisen condensation results:
b-keto ester

8. Examples 2 a-H required to send reaction to the Claisen product
Always need acid in second step to quench anion

9. Intramolecular Claisen Condensation – the Dieckmann
Both the nucleophile (enolate) and electrophile are now in same system
Intramolecular Claisen condensation results – cycle formed
Protonation still required to isolate b-keto ester product