Cationic polymerization of cyclic ketene acetals via zwitterion formation with cyanoallene

Abstract

This article deals with the polymerization of the cyclic ketene acetals (CKAs) 2‐methylene‐4‐phenyl‐1,3‐dioxolane (2), 2‐methylene‐4‐phenyl‐1,3‐dioxane (3), 4,7‐dimethyl‐2‐methylene‐1,3‐dioxepane (4), 2‐ethylidene‐4‐phenyl‐1,3‐dioxolane (5), 2‐phenylmethylene‐1,3‐dioxolane (6), and 2‐isopropylidene‐4‐phenyl‐1,3‐dioxolane (7) in the presence of cyanoallene (1). For 2 and 3, the homopolymerization of the CKAs proceeded without ring opening, and the number‐average molecular weights of the obtained polymers depended on the feed ratio of 1. However, the reactions of 1 with 4–7 afforded no polymers but did afford spirocyclic 1 : 1 adducts possessing cyclobutane rings. © 2000 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 38: 2075–2081, 2000

Radical Ring-Opening Polymerization: Scope, Limitations, and Application to (Bio)Degradable Materials

“…228 A similar interaction was already described by Cho and co-workers between CKA11 and AN also leading to limited ring-opening (7−10%). 246 In the eighties, Endo and co-workers investigated the spontaneous copolymerization of CKA (MDP/MDO CKA27 and MPDO/MPDL CKA11) with various electrophilic compounds (heterocumulenes such as CS 2 , 251 cyanoallene, 252 βpropiolactone, 253 and vinyl monomers, for example, methyl αcyanoacrylate, 254,255 MMA, 255 AN, 255 etc.). They reported the preparation of copolymers via a pure zwitterionic mechanism.…”

“…In the eighties, Endo and co-workers investigated the spontaneous copolymerization of CKA (MDP/MDO CKA27 and MPDO/MPDL CKA11 ) with various electrophilic compounds (heterocumulenes such as CS 2 , cyanoallene, β-propiolactone, and vinyl monomers, for example, methyl α-cyanoacrylate, , MMA, AN, etc.). They reported the preparation of copolymers via a pure zwitterionic mechanism.…”

A paradigm for the mechanisms and products of spontaneous polymerizations

“…Endo and coworkers proposed the use of a cyclic ketene acetal, 2‐methylene‐4‐phenyl‐1,3‐dioxolane (CKA) as a diagnostic donor olefin: with a less electrophilic olefin, the phenyl group would skew the polymerization toward ring opening in free radical polymerization, in accordance with Bailey's early work,57 whereas with a highly electrophilic olefin, cationic polymerization would proceed only through the double bond 58–60. In this fashion, this electron‐rich olefin could give a quantitative measure of radical or ionic character of the P intermediates.…”

Radical Ring-Opening Copolymerization of Cyclic Ketene Acetals and Maleimides Affords Homogeneous Incorporation of Degradable Units

“…We hypothesized that the vastly different reaction of MPDL with MAnh and NEtMI may be due to the increased electrophilicity of MAnh as compared to MIs, especially given the electron-rich nature of CKA methylene bonds . Indeed, several reports have demonstrated that spontaneous polymerizations and cyclization reactions can occur between CKAs and electrophilic compounds, including cyanoallene, β-propiolactone, tulipalin A, cyanoacrylate, and methyl methacrylate . The generally accepted mechanism of these reactions is believed to follow the “bond-forming initiation theory” established by Hall in the 1980s, in which charge transfer complexes initiate ionic or radical reactions via a tetramethylene intermediate (Figure A) .…”