Specific formation of a polymer containing five-membered oxalactone rings in the main chain in the cationic ring-opening polymerization of 6,8-dioxabicyclo[3.2.1]octan-7-one

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

“…In addition, peaks assigned to the methylene protons of the DOLO-adjacent IBO units were observed at 3.3−3.7 ppm (peaks 1, 7, and 9) due to the effects of the adjacent ester and acetal moieties, and peaks were not observed at these positions in the spectrum of the homopolymer of IBO (Figure 2C). These assignments were confirmed by analyses of the 13 C and 2D NMR spectra (Figures S1−S4). The average numbers of units of IBO and 2 per block were estimated to be 2.7 and 1.0, respectively, from the 1 H NMR spectrum (Figure 2A), which indicates that crossover reactions occurred very frequently and that homopropagation of DOLO did not occur.…”

“…On the basis of these previous works, we focused on 1,3-dioxolan-4-ones (DOLOs; Scheme A) as candidate monomers for cationic copolymerizations via crossover reactions. DOLOs have been synthesized via the condensation of α-hydroxy acids, such as lactic acid, glycolic acid, and mandelic acid, with aldehydes or ketones since the late 1800s. − However, to the best of our knowledge, cationic polymerizations of DOLOs have not been reported. We thought that a DOLO monomer could potentially react with a cationic species through an attack by a carbonyl group in a manner similar to that seen with ketones and subsequently undergo a ring-opening reaction to generate an oxygen-adjacent carbocation, which would be structurally similar to a VE-derived carbocation, as shown in Scheme B.…”

Cationic Ring-Opening Oligomerization of the Two Stereoisomers of 4-Bromo-6,8-dioxabicyclo[3.2.1]octan-7-one

“…In this connection, a linear polymer containing fivemembered oxalactone ( 1,3-dioxolan-4-one) rings (7) in the backbone chain was obtained in the cationic polymerization of the parent monomer 1 at 0°C. 21 This polymer is not formed directly by the ring-opening polymerization of 1 but by the isomerization of the once-formed polyester or oligoester chains. Therefore, it appears that also in the present oligomerization, a similar side reaction takes place, although not so rapidly as in the polymerization of 1, to yield linear oligomeric products.…”

Hemiacetal Ester Exchanges, Study of Reaction Conditions and Mechanistic Pathway

“…Hemiacetal esters, also called acylated hemiacetals, (see Scheme 1), possess a very interesting functional group, which has yet to be fully studied. It can be synthesized by a number of methods, such as through the addition of a carboxylic acid onto a vinyl ether [1], through Baeyer-Villiger oxidation of a cyclic ketone bearing a vicinal methoxy group [2], or through reaction of a ketone or acetaldehyde with β-hydroxy acids [3]. This function has mostly been used for its ability to dissociate under specific conditions.…”

“…Butoxyethyl nonanoate (BEN) 1 H NMR (400 MHz, CDCl 3 , δ = ppm), FigureS1: δ = 0.86 (t, 3H, CH 3 -CH 2 ,3 J HH = 7.1 Hz), δ = 0.90 (t, 3H, CH 3 -CH 2 , 3 J HH = 7.4 Hz), δ = 1 25. 1.45 (m, 2H, CH 2 -CH 2 -CH 3 ; 10H, CH 2 -CH 2 -CH 2 ), δ = 1.37 (d, 3H, OOC-CHCH 3 -O, 3 J HH = 5.2 Hz), δ = 1.5-1.6 (m, 2H, CH 2 -CH 2 -CH 2 -O-CHCH 3 -O), δ = 1.61 (q i , 2H, CH 2 -CH 2 -CH 2 -COO), δ = 2.3 (dt, 2H,CH 2 -CH 2 -COO, 2 J HH = 1.3 Hz, 3 J HH = 7.5 Hz), δ = 3.45 (dt, 1H, CH 2 -CH A H B -O-CHCH 3 -O, 2 J HH = 9.5 Hz, 3 J HH = 6.7 Hz), δ = 3.62 (dt, 1H, CH 2 -CH A H B -O-CHCH 3 -O, 2 J HH = 9.5 Hz, 3 J HH = 6.6 Hz), δ = 5.91 (q a , 1H, OOC-CHCH 3 -O, 3 J HH = 5.2 Hz).…”