Carbonylative Polymerization of Propylene Oxide: A Multicatalytic Approach to 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

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

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

P3HB Cat. Introduction Co 2 CO 8 2. The direct Copolymerization of CO and PO

P3HB Disadvantages; Low monomer conversion and low molecular weight Introduction Co 2 CO 8 2. The direct Copolymerixation of CO and PO

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

No need to isolate and purify the toxic lactone monomer

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.

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.