Lactide Cyclopolymerization by an Alumatrane-Inspired Catalyst

Abstract

Scheme 1. Ligand and Catalyst Synthesis a a Key: (a) C 7 H 8 , reflux. (b) 0.01 M 2, AlMe 3 , THF, reflux, N 2 , 5 days. Note pubs.acs.org/Macromolecules

Cyclic Polyester Formation with an [OSSO]‐Type Iron(III) Catalyst

“…[4] Indeed, av ery high degree of control over the polymerization process has been achieved, which offerst he possibility to obtain polymers with predictable molecular weights, compositions,a nd microstructures. Actually, the number of reports in which the production of cAPEs by means of aw ell-defined metal complex is described is limited, [24] and mosti nvolve the use of Al- [25][26][27] and Zn-based catalysts. [6] Different approaches have been proposed for the production of cyclic polymers, [7] andnotable examples have been reported in literature.…”

“…[8] However,t he formation of cyclic polyesters remains a challenge. Actually, the number of reports in which the production of cAPEs by means of aw ell-defined metal complex is described is limited, [24] and mosti nvolve the use of Al- [25][26][27] and Zn-based catalysts. Indeed,t he biodistribution of cyclic aliphatic polyesters (cAPEs)i sd ifferent from that of linear APEs, [10] which offers an opportunity to develop new drug deliverys ystems.…”

Zinc complexes supported by (benzimidazolyl)pyridine alcohol ligands as highly efficient initiators for ring-opening polymerization of ε-caprolactone

“…The repeated coordination and insertion of ε-CL successively occurred and the final intramolecular transesterification led to the formation of cyclic polymers. Cyclic polyesters have been achieved with the NHCmediated zwitterionic ROP of lactones [57], or metal catalyzed ringexpansion polymerization of cyclic esters, such as lithium complexes [56], aluminum complexes [32,58], tin(II) complexes [59], and Zn(C 6 F 5 ) 2 -based Lewis pairs [60]. The addition of BnOH resulted in the transformation of active species from LZnÀCH 3 to LZnÀOBn.…”

Interactions between cyclic oligo(l-lactic acid) and alkali metal ions in organic solvent

“…Many studies related to linear PLA [1][2][3][4][5] are available in the literature, while there are fewer studies on cyclic poly or oligo(lactic acid). For example, c-PLLA with molecular weight ranging from approximately 4000 to 39,000 (60-540 repeat units) was synthesized using an alumatrane-inspired catalyst [6]. Shin et al prepared c-PLLA by zwitterionic polymerization of lactide using N-heterocyclic carbene 1,3-dimesitylimidazol-2-ylidene as the catalyst in order to investigate the crystallinity of the polymer [7].…”