Ring-opening polymerization of a 2,3-disubstituted oxirane leading to a polyether having a carbonyl–aromatic π-stacked structure

Abstract

Ring-opening polymerization of a 2,3-disubstituted oxirane afforded a polyether exhibiting intramolecular charge-transfer (ICT) interactions due to a carbonyl–aromatic π-stacked conformation.

Stopped‐Flow Enantioselective HPLC‐CD Analysis and TD‐DFT Stereochemical Characterization of Methyl Trans‐3‐(3,4‐Dimethoxyphenyl)Glycidate

“…Racemic methyl trans‐ 3‐(3,4‐dimethoxyphenyl)glycidate ( rac‐trans ‐ 3 ) was synthesized by Darzens reaction, according to a reported procedure; veratraldehyde and methyl chloroacetate were purchased from TCI (Tokyo, Japan). The enantiomers of trans ‐ 3 were then obtained by preparative HPLC collection performed on an Agilent (Waldbronn, Germany) 1200 HPLC system equipped with a G1367C HiP ALS‐SL autosampler, a G1316B TCC‐SL temperature controller, a G1311A quaternary pump, a G1314D VWD variable wavelength detector (detection wavelength: 220 nm), and the Chemstation software package (v. B.03.02‐SR2) for instrument control and data processing.…”

“…1). 9 The structure of polymer 4 was found to be linear, despite the low reactivity of bulky 2,3-disubstituted oxiranes and the possible formation of branched polymers by Friedel-Crafts alkylation of the aromatic substituent. However, the stereoselectivity of the mechanism of ring opening and the stereochemistry of the resulting backbone are not fully characterized; the first step needed for the elucidation of these aspects is the assessment of the absolute configuration of the building block.…”

“…), a fully methylated analog of the natural polyethers 1 and 2 (Fig. ) . The structure of polymer 4 was found to be linear, despite the low reactivity of bulky 2,3‐disubstituted oxiranes and the possible formation of branched polymers by Friedel‐Crafts alkylation of the aromatic substituent.…”

Polymerization of Bulky of Oxirane Monomers Leading to Polyethers Exhibiting Intramolecular Charge Transfer Interactions

“…In spite of the bulky structure, MDMPO was found to yield a polyether, and the resulting polymer had a rather stiff conformation leading to intramolecular charge transfer (ICT) interactions. It has been also reported that 2‐ethoxycarbonyl‐3‐phenyloxirane (EPO) does not yield a polymer as the major product but only small molecules including diethyl 3,6‐diphenyl‐1,4‐dioxane‐2,5‐dicarboxylate and ethyl 2‐benzyl‐4‐hydroxy‐5‐oxo‐3‐phenyl‐2,5‐dihydrofuran‐2‐carboxylate having cyclic structures 3. This aspect implies that the two methoxy groups on the benzene ring of MDMPO have important role in preventing cyclization and promoting polymerization.…”

“…We have recently reported the synthesis and cationic polymerization of 2-methoxycarbonyl-3-(3,4dimethoxyphenyl)oxirane (MDMPO) as an unsymmetrically 2,3-disubstituted oxirane monomer. [3] Poly(MDMPO) was designed on the basis of poly [2-hydroxycarbonyl-3-(3,4-dimethoxyphenyl)oxirane] [4,5] (poly [3-(3,4-dihydroxyphenyl)glyceric acid]) which is proposed to be an important ingredient contained in folk medicines widely used in southern European countries. In spite of the bulky structure, MDMPO was found to yield a polyether, and the resulting polymer had a rather stiff conformation leading to intramolecular charge transfer (ICT) interactions.…”