Preparation of Stereoregular Isotactic Poly(mandelic acid) through Organocatalytic Ring‐Opening Polymerization of a Cyclic O‐Carboxyanhydride

Abstract

Poly(mandelic acid) (PMA) is an aryl analogue of poly(lactic acid) (PLA) and a biodegradable analogue of polystyrene. The preparation of stereoregular PMA was realized using a pyridine/mandelic acid adduct (Py⋅MA) as an organocatalyst for the ring-opening polymerization (ROP) of the cyclic O-carboxyanhydride (manOCA). Polymers with a narrow polydispersity index and excellent molecular-weight control were prepared at ambient temperature. These highly isotactic chiral polymers exhibit an enhancement of the glass-transition temperature (T(g)) of 15 °C compared to the racemic polymer, suggesting potential future application as high-performance commodity and biomedical materials.

Enzymatic Resolution by a d‐Lactate Oxidase Catalyzed Reaction for (S)‐2‐Hydroxycarboxylic Acids

“…Accordingly, numerous optically pure ( R )‐2‐HAs have been produced using these l ‐2‐hydroxy acid oxidases that catalyze the oxidation of ( S )‐2‐HAs in racemic 2‐HAs . ( S )‐2‐HAs are as important chiral precursors for the synthesis of diverse functional compounds as ( R )‐2‐HAs . Skopan et al.…”

“…[14] (S)-2-HAs are as important chiral precursors for the synthesis of diversef unctional compounds as (R)-2-HAs. [15] Skopan et al andY amada et al did pioneering work on the production of several(S)-2-HAs through an isopropylmalate dehydrogenase (which required NAD as ac ofactor) [16] and a Mo-containing 2-oxocarboxylate reductase( whichr equired carbamoylmethylviologen as an artificial acceptor). [17] As in the situation of (R)-2-HA production,i ti sd esirable to explore the d-2-hydroxy acid oxidasest hat do not requiree xpensive cofactors (or artificial electron acceptors) and exhibit broad substrate spectra for the production of various valuable (S)-2-HAs.…”

Controlled Ring‐Opening Polymerization of O‐Carboxyanhydrides Using a β‐Diiminate Zinc Catalyst

“…Poly(1)a nd poly(2)p olymerized by DMAP showed good stereoregularity judged by NMR (Figure S17, 19). [8,13] On the other hand, all PA HAs mediated by (BDI)Zn-1 showed perfect stereoregularity.N arrow singlets for backbone amethine hydrogens were observed in the homonuclear decoupled 1 HNMR spectra, revealing > 95 %i sotacticity [16a] for all PA HAs (Figure 1, Figures S4, S7, and S15). [8,13] On the other hand, all PA HAs mediated by (BDI)Zn-1 showed perfect stereoregularity.N arrow singlets for backbone amethine hydrogens were observed in the homonuclear decoupled 1 HNMR spectra, revealing > 95 %i sotacticity [16a] for all PA HAs (Figure 1, Figures S4, S7, and S15).…”

“…[8] OCAs are mostly polymerized using pyridine-based organocatalysts,s uch as dimethylaminopyridine (DMAP), into the corresponding PA HAs through anon-covalent basic/ alcohol activation mechanism. [8,13] This results in epimerization of the a-carbon atom, and loss of stereoregularity in the PA HA backbone,which leads to changes in the properties of the final polymers. [8,13] This results in epimerization of the a-carbon atom, and loss of stereoregularity in the PA HA backbone,which leads to changes in the properties of the final polymers.…”

Ring‐Opening Polymerization of a New Diester Cyclic Dimer of Mandelic and Glycolic Acid: An Efficient Synthesis Method for Derivatives of Amorphous Polyglycolide with High Tg

“…Due to its high T g , PMA is considered as one of the most promising candidates to replace petroleum‐derived polystyrene. To add to this, there is also a reported case of a crystallizable PMA of isotactic tacticity . It is prepared by ROP of O‐ carboxyanhydride (OCA), exhibiting an outstanding T m of 316 °C.…”