Cationic Ring-Opening Co- and Terpolymerizations of Lactic Acid-Derived 1,3-Dioxolan-4-ones with Oxiranes and Vinyl Ethers: Nonhomopolymerizable Monomer for Degradable Co- and Terpolymers

Abstract

Lactic acid-derived 1,3-dioxolan-4-ones (DOLOs), which do not undergo cationic homopolymerization, were demonstrated to yield copolymers with oxiranes through a cationic copolymerization via frequent crossover reactions. Acetal and ester moieties were generated in the main chain of the copolymers via crossover reactions from DOLO to oxirane and from oxirane to DOLO, respectively, which is in contrast to the unsuccessful generation of hemiacetal ester moieties in the homopropagation of DOLO. In addition, the terpolymerization of DOLO, oxirane, and vinyl ether (VE) proceeded via crossover reactions, while copolymers could not be generated from VE and DOLO in the absence of oxirane. The obtained co- and terpolymers could be degraded under acidic conditions due to the acetal moieties in the main chain. The strategy devised in this study shows a promising avenue for employing plant-derived “nonhomopolymerizable” compounds as building blocks for the synthesis of degradable co- and terpolymers with general-purpose monomers.

Living Cationic Ring-Opening Homo- and Copolymerization of Cyclohexene Oxide by “Dormant” Species Generation Using Cyclic Ethers as Lewis Basic Additives

“…2,2-Dimethyl-1,3-dioxepane (DMDOP) was synthesized and purified as reported in our previous study . 2-Methyl-5-phenyl-1,3-dioxolan-4-one (MePhDOLO) was synthesized by condensation of d -(−)-mandelic acid (TCI, >99.0%) with paraldehyde (TCI, >98.0%) using p -toluenesulfonic acid (monohydrate; TCI, >98.0%) and purified in a manner similar to the purification of the 1,3-dioxolan-4-one derivatives. , Triphenylmethylium tetrakis­(pentafluorophenyl)­borate (Ph 3 CB­(C 6 F 5 ) 4 ; TCI, >98.0%), triphenylmethylium hexafluorophosphate (Ph 3 CPF 6 ; Sigma-Aldrich), triphenylmethylium tetrafluoroborate (Ph 3 CBF 4 ; Sigma-Aldrich), and triethyloxonium hexafluorophosphate (Et 3 OPF 6 ; Sigma-Aldrich, containing diethyl ether (10–20%) as a stabilizer) were used as received. Commercially available TfOH (Aldrich, ≥99.0%) and Tf 2 NH (Wako, 98.0+%) were used without further purification after preparing their stock solutions in dichloromethane.…”

Ring opening copolymerization of δ-valerolactone with 2-methyl-1,3-dioxane-4-one towards poly(3-hydroxypropionate-co-5-hydroxyvalerate) copolyesters

“…Recently, multiple measures have been taken to develop poly(acetal-ester)s and polyacetals. [24][25][26][27][28][29][30][31] 2-Methyl-1,3-dioxane-4one (MDO) as a kind of cycloacetal ester has both an ester group and an acetal bond, [32][33][34][35][36] and showed an unprecedented result during its Et 2 Zn catalyzed ROP, where poly(hemiacetal ester) (PMDO) was obtained at a low ratio of catalyst/initiator (low [Zn]) and the polyester (P3HP) was obtained at a high ratio of catalyst/initiator (high [Zn]). MDO as an alternative β-PL is accessible for the synthesis of P3HP.…”

Cationic Polymerizability of Vinyl Acetate: Alternating Copolymerization with 1,3-Dioxolan-4-ones and Branched Copolymer Formation with Cyclic Acetals

“…Homopolymerization of DOLO-1 did not proceed (entry 9) as in the case of our previous study. 12 1 H NMR analysis of the copolymerization product revealed that the polymer chains consisted mostly of alternating sequences of VAc and DOLO-1 (Figure 2A). A peak at 6.9 ppm (peak e) was assignable to the VAc-derived methine group adjacent to the acetoxy group and the DOLO-derived oxygen atom.…”

“…Unlike their six-membered counterparts, 11 DOLOs do not exhibit cationic homopolymerizability, but copolymers are produced by cationic copolymerization when DOLOs are combined with oxiranes, as reported in our previous study. 12 Cyclic acetals with low ring strain are not homopolymerizable due to their low ceiling temperature (for high equilibrium concentration), 13−22 whereas copolymerizations proceed when suitable comonomers are added, as in the cases of 1,3-dioxane (DOX) copolymerizations with cyclic acetals or cyclic ethers. 23−25 These nonhomopolymerizable monomers potentially react with VAc to generate copolymers via the cationic pathway.…”