Acidity Reversal Enables Site-Specific Ring-Opening Polymerization of Epoxides from Biprotonic Compounds

Area of Science:

• Polymer Chemistry
• Organic Synthesis
• Materials Science

Background:

• Polyethers are widely used but incorporating amine functionality is challenging.
• Anionic ring-opening polymerization (ROP) of epoxides requires protecting amine groups due to their nucleophilicity.
• Existing methods often involve harsh conditions or complex protecting group strategies.

Purpose of the Study:

• To develop a streamlined synthesis of amino-functionalized polyethers.
• To utilize N-carbamate-protected aminoalcohols as initiators for epoxide ROP.
• To achieve controlled polymerization while preserving amine functionality.

Main Methods:

• Anionic ring-opening polymerization (ROP) of epoxides.
• Use of N-carbamate-protected aminoalcohols as initiators.
• Employing a Lewis acid-excess two-component organocatalytic system.

Main Results:

• Efficient ROP of epoxides was achieved using the organocatalytic system.
• The carbamate protecting group remained intact throughout the polymerization.
• The synthesized poly(propylene oxide) and poly(ethylene oxide) had controlled molar mass and low dispersity.
• Amino functionalities were preserved and used to create hybrid block copolymers.

Conclusions:

• A robust and efficient method for synthesizing amino-functionalized polyethers was established.
• The organocatalytic system enables site-specific polymerization via an acidity-reversing effect.
• This approach facilitates the creation of advanced polymer architectures, such as polypeptoid-based hybrid block copolymers.