Metathesis-Sourced Epoxides in Ring-Opening Copolymerization: Selective Access to Degradable Polythioesters.

Area of Science:

• Polymer Chemistry
• Organic Synthesis
• Materials Science

Background:

• Controlled synthesis of degradable polymers is crucial for sustainable materials.
• Ring-opening copolymerization (ROCOP) offers a pathway to well-defined polymer architectures.
• Development of novel monomers is key to expanding ROCOP capabilities.

Purpose of the Study:

• To synthesize novel ester-substituted cyclopentene epoxides.
• To investigate their utility as monomers in controlled ring-opening copolymerization (ROCOP).
• To produce well-defined degradable polyesters and polythioesters.

Main Methods:

• Synthesis of cyclopentene epoxides via ring-closing metathesis and epoxidation.
• Ring-opening copolymerization (ROCOP) with phthalic thioanhydride (PTA) and phthalic anhydride (PA).
• Optimization of monomer purity, catalyst preparation, and reaction conditions.

Main Results:

• Selective access to monomers for controlled ROCOP achieved.
• Fully alternating PTA/epoxide ROCOP yielded well-defined poly(ester-alt-thioester)s (Mw up to ~38 kg/mol).
• Successful phthalic anhydride (PA) ROCOP and selective terpolymerizations demonstrated; substituent variation confirmed scaffold robustness.

Conclusions:

• Metathesis-derived cyclopentene epoxides are versatile and accessible monomers.
• These monomers enable controlled synthesis of degradable polyesters and polythioesters.
• The study establishes a new route to advanced degradable polymer materials.