Trisubstituted Ethylenes Containing Halo, Cyano and Carbomethoxy Substituents. Comonomers.

A paradigm for the mechanisms and products of spontaneous polymerizations

“…In our research, we have emphasized the use of highly reactive donor and acceptor monomers to bring about reactions at room temperature or below, which amplifies the behavior of the weakly electrophilic character of commercial monomers, such as methyl acrylate and acrylonitrile; this avoids heating which might cause adventitious side reactions 21, 22. Starting from our “standard” monomer combination, p ‐methoxystyrene and dimethyl cyanofumarate, several closely related monomer combinations were investigated: p ‐methoxystyrene with trimethyl ethylenetricarboxylate at 28 °C also led to alternating copolymers via P4 biradicals; dimethyl 2,2‐dicyanoethylene‐1,1‐dicarboxylate with styrene or p ‐methylstyrene gave alternating copolymers and cyclobutane, via P4 biradicals, whereas p ‐methoxystyrene as comonomer led to formation of homopolymer and cyclobutane, indicating that the character of the P4 intermediate could be switched to P4 zwitterionic character23, 24; methyl tricyanoethylenecarboxylate did not lead to spontaneous polymerization with electron‐rich olefins, giving cyclobutane instead, mimicking the behavior of TCNE (tetracyanoethylene) 25…”

Organic and polymer chemistry of electrophilic tri‐ and tetrasubstituted ethylenes

“…This unexpected result drew our attention to electrophilic trisubstituted ethylenes, and starting with the work of Bob Daly, we eventually synthesized all possible ethylenes trisubstituted with ester and cyano groups 2–4. Ester substituents are moderately electron‐attracting, whereas cyano substituents are strongly so.…”

“…Trisubstituted ethylenes do not homopolymerize because of a ceiling temperature effect. To establish the structural generality of this new class of comonomers, we examined their copolymerizations with electron‐rich vinyl monomers and encountered remarkably diverse behavior 2–4. With somewhat electron‐rich and electron‐poor groups, initiated alternating free‐radical copolymerization can be accomplished.…”

“…Olefins with halogens as electron‐attracting groups at the β position present a new facet because the halogen can act as a leaving group 3, 66–68. Even when diradical character is expected, the tetramethylene intermediate expels halide ions and initiates the cationic homopolymerization of donor monomers.…”

Synthesis and vinyl benzene copolymerization of novel trisubstituted ethylenes: 15. Halogen and methoxy ring-substituted isopropyl 2-cyano-3-phenyl-2-propenoates

“…Most CPP compounds do not undergo homopolymerization because of steric difficulties but copolymerize readily with monosubstituted alkenes [10]. Trisubstituted alkenes substituted with carbonyl, cyano, and halo groups when copolymerized with monomers like vinyl benzene, N-vinylcarbazole, and vinyl acetate [11][12][13] form alternating copolymers with isolated CPP monomer units. When copolymerized with such commercial monomers, (i.e., vinyl benzene, vinyl, acetate, and vinyl ethers), CPP monomers introduce into polymer chain a variety of functional groups, like cyanoacrylate, substituted phenyl ring, etc.…”