Synthesis of Stereocontrolled Degradable Polymer by Living Cascade Enyne Metathesis Polymerization

Abstract

A stereocontrolled degradable polymer was synthesized via living cascade enyne metathesis polymerization. Highly stereodefined N,O‐acetal‐containing enyne monomers were prepared using the Pd‐catalyzed hydroamination of alkoxyallenes and ring‐closing metathesis. The resulting chiral polymer exhibited a narrow dispersity window. Block copolymers were prepared not only by sequentially adding nondegradable and degradable monomers but also by using enantiomerically different monomers to produce stereocontrolled blocks. Owing to the hydrolyzable N,O‐acetal moiety in the backbone structure, the resulting polymer could degrade under acidic conditions generated using various acid concentrations to control the degradation. Additionally, the aza‐Diels–Alder reaction modified the polymer without losing the stereochemistry.

Recent Advances in Environmentally Friendly Dual‐crosslinking Polymer Networks

“…[35,38] In this context, there has been significant investment in developing main chain degradable and recyclable polymers. Over recent years, several innovative polymers have been introduced, including thioestercontaining polymers, [92] N,O-acetal-containing polymers, [93] enyne self-immolative polymers, [94] silyl ether-containing polymers, [95] and copolymers consisting of cleavable segments. [48c,96] Most of them are not only degradable or recyclable, but also mechanically comparable to conventional vinyl polymers.…”