Erin W. Dunn and Geoffrey W. Coates*

1. Carbonylative Polymerization of Propylene Oxide: A Multicatalytic Approachto the Synthesis of Poly(3-Hydroxybutyrate) Erin W. Dunn and Geoffrey W. Coates* Department of Chemistry and Chemical Biology, Baker Laboratory, Cornell University, Ithaca, New York J. AM. CHEM. SOC. 2010, 132, 11412–11413 Kittisak Choojun Chisholm’s group meeting

2. Introduction Poly(3-hydroxybutyrate) [P3HB] • Naturally occurring biodegradable and biocompatible polyester • - Properties similar to isotactic polypropylene There are three ways to synthesize P3HB.

3. Introduction 1. Bacterial fermentation • The process is energy-intensive and necessitates polymer separation from the bacterial culture.

4. Co2CO8 Introduction 2. The direct Copolymerization of CO and PO Cat. P3HB

6. Introduction 2. The direct Copolymerixation of CO and PO Co2CO8 P3HB Disadvantages; Low monomer conversion and low molecular weight

7. Introduction 3. The living ring opening polymerization(ROP) of β-butyrolactone(BBL) Cat. ROP of BBL yields a high MW polyester; however, it requires the rigorous purification of a toxic lactone.

8. No need to isolate and purify the toxic lactone monomer

9. Challenging • The two catalysts must be compatilbe not only with each other but also with solvent, substrate, and reaction side products in order to achieve high activity and selectivity.

19. Conclusion • A new atom-economical and highly efficient method for the synthesis of P3HB from the carbonylative polymerization of propylene oxide. • The use of compatible catalysts allows for a one-pot reaction that eliminates the need to isolate and purify toxic BBL intermediate.