Controlled Ring-Opening Polymerization of O-Carboxyanhydrides to Synthesize Functionalized Poly(α-Hydroxy Acids)

Abstract

Poly(α-hydroxy acids), as a family of biodegradable polyesters, are valuable materials due to their broad applications in packaging, agriculture, and biomedical engineering. Herein we highlight and explore recent advances of catalysts in controlled ring-opening polymerization of O-carboxyanhydrides towards functionalized poly(α-hydroxy acids), especially metal catalyst-mediated controlled polymerization. Limitations of current polymerization strategies of O-carboxyanhydrides are discussed.

Recent advances in enantioselective ring-opening polymerization and copolymerization

“…Enantioselective polymerization of epoxide/anhydride Aliphatic polyesters are commonly made through ROP of lactones 26,28,40,160 . The resulting polyesters have a limited range of properties owing to the lack of functional diversity of available lactones [161][162][163] . An alternative chain-growth route to both aliphatic and semi-aromatic polyesters is the alternating copolymerization of epoxides and cyclic anhydrides, which has emerged in recent 10 years and has been reviewed elsewhere 12,31,129,132 .…”

Recent Advances in Sequence‐Controlled Ring‐Opening Copolymerizations of Monomer Mixtures

“…In many cases, the obtained MWs of copolymers may not be adequate to prepare materials with decent thermo-mechanical properties comparable to commodity polyolefins. In Table 3, we highlight thermomechanical properties of the sequence-controlled copolymers produced using the above one-pot copolymerization strategies (note that we did not include copolymers synthesized by the same type of monomers with different pendant groups [2,7,50,186,238,243,273,274] ). In the context of chemical sustainability, it is anticipated that such powerful polymerization strategies will therefore find utility and contribute to the industrial adoption of polymers from renewable monomer resources.…”

“…O-carboxyanhydride (OCA) has gained significant attention over the last decade because it allows easy access to functionalized poly(α-hydroxy acids). [34,[182][183][184][185][186] OCA can bear various functional groups, and thereby offers the manipulation of physicochemical, thermal, and mechanical characteristics to the polyesters. [2,186,187] The ROP of OCA can proceed at mild conditions as the liberation of CO 2 from OCA relieves the ring strain, which enables OCA to become more reactive compared to LA.…”

“…[34,[182][183][184][185][186] OCA can bear various functional groups, and thereby offers the manipulation of physicochemical, thermal, and mechanical characteristics to the polyesters. [2,186,187] The ROP of OCA can proceed at mild conditions as the liberation of CO 2 from OCA relieves the ring strain, which enables OCA to become more reactive compared to LA. [188] Recently, Chen and coworkers reported the copolymerization of OCA/LA using a (salen)Mn III Cl complex in neat CHO at 40 °C (Scheme 12a).…”

“…O ‐carboxyanhydride (OCA) has gained significant attention over the last decade because it allows easy access to functionalized poly(α‐hydroxy acids) [34,182–186] . OCA can bear various functional groups, and thereby offers the manipulation of physicochemical, thermal, and mechanical characteristics to the polyesters [2,186,187] .…”