Kinetic Resolution Polymerization Enabled Chemical Synthesis of Perfectly Isotactic Polythioesters

Area of Science:

• Polymer Chemistry
• Organic Synthesis
• Materials Science

Background:

• Isotactic polythioesters (PTEs) are analogs to natural polyhydroxyalkanoates (PHAs) with unique properties.
• Chemical synthesis of isotactic PTEs remains challenging.
• Developing efficient synthetic routes is crucial for accessing novel polymer materials.

Purpose of the Study:

• To report a successful stereocontrolled synthesis of perfectly isotactic PTEs.
• To explore the properties and applications of these novel polymers.
• To establish a versatile platform for producing sustainable plastics and pharmaceutical intermediates.

Main Methods:

• Stereocontrolled ring-opening polymerization using a binaphthalene-salen aluminium (SalBinam-Al) catalyst.
• Polymerization of rac-α-substituted-β-propiothiolactones (rac-BTL and rac-PTL) with high kinetic resolution.
• Characterization of polymer properties, including molecular weight and thermal properties.

Main Results:

• Achieved synthesis of perfectly isotactic P(BTL) and P(PTL) with high molecular weights (up to 276 kDa).
• Demonstrated formation of a supramolecular stereocomplex of isotactic P(BTL) with enhanced thermal stability (Tm = 204°C).
• Facilitated isolation of enantiopure (S)-BTL for pharmaceutical applications and PTL as a robust material.

Conclusions:

• The developed catalytic system provides efficient access to isotactic PTEs.
• Isotactic PTEs exhibit promising properties for advanced materials and sustainable plastics.
• This work opens avenues for the synthesis of valuable chiral building blocks.