Dynamic Kinetic Resolution Polymerization: Synthesis of Chiral Polythioesters from Racemic Monomers.

Area of Science:

• Polymer Chemistry
• Organic Synthesis
• Materials Science

Background:

• Chiral polymers are crucial in nature and scientific research.
• Traditional kinetic resolution polymerization (KRP) of racemic monomers yields only 50% chiral polymer with 50% unreacted monomer.
• A need exists for more efficient methods to synthesize chiral polymers from racemic precursors.

Purpose of the Study:

• To develop a dynamic kinetic resolution polymerization (DKRP) strategy for chiral polymer synthesis.
• To achieve complete monomer conversion and enhanced isoselectivity from racemic monomers.
• To explore the synthesis of chiral polythioesters using a novel catalytic system.

Main Methods:

• Development of a "Lewis acid/base-SalBinamAl" catalytic system.
• Application of the catalytic system to perform dynamic kinetic resolution ring-opening polymerization (DKRP) of thiolactones.
• Characterization of chiral polythioesters using circular dichroism spectroscopy and optical rotation testing.
• Detailed kinetic investigation to elucidate the DKRP mechanism.

Main Results:

• Successful implementation of DKRP for chiral polymer synthesis with full monomer conversion.
• Access to chiral polythioesters with high isotacticities (P_m up to 0.99).
• Confirmation of chiral polythioester formation through spectroscopic and optical methods.
• Kinetic studies supporting the proposed DKRP mechanism.

Conclusions:

• The developed DKRP strategy enables efficient synthesis of chiral polymers from racemic monomers.
• This work represents the first instance of dynamic kinetic resolution in ring-opening polymerization.
• The findings offer a new conceptual approach for synthesizing chiral polymers, inspiring future research.