Chemoselective RAFT Polymerization of a Trivinyl Monomer Derived from Carbon Dioxide and 1,3-Butadiene: From Linear to Hyperbranched

Abstract

3-Ethylidene-6-vinyltetrahydro-2H-pyran-2-one (EVL), a substituent δ-lactone synthesized through telomerization of CO2 with 1,3-butadiene, is highly functionalized containing a six-membered ring and two vinyl groups. It can hardly be polymerized directly through common methods due to its poor polymerizability. In this paper, we report the controlled polymerization of a highly reactive trivinyl monomer derived from EVL, i.e. methyl-2-ethylidene-5-hydroxyhept-6-enoate methacrylate (MEDMA), which is synthesized through ring cleavage of EVL and subsequent esterification with methacryloyl chloride. Chemoselective RAFT polymerizations of MEDMA mediated by 2-cyanoprop-2-yl-dithiobenzoate (CPDB) are achieved and well-defined polymers with linear and hyperbranched topologies are obtained under optimized polymerization conditions. RAFT polymerizations show good control in producing linear PMEDMAs with predetermined molecular weights (4000 g/mol) and moderate polydispersity indices (below 1.22). The resultant hyperbranched PMEDMAs are fully characterized by 1H NMR, 13C NMR, 1H–13C HMQC, DEPT, DLS, and TEM. The incorporations of vinyl group in allylic ester into polymer chains lead to the hyperbranched topology. Both PMEDMAs are ready for the introduction of amino and carboxy groups through thiol–ene click chemistry, and the products self-assemble to the micelles with different morphologies. This protocol develops the utilization of EVL in synthetic polymers and is significant to the carbon dioxide transformation.

The Ultrasmall Palladium Nanoparticles Catalyzed Telomerization of CO2 with 1,3‐Butadiene at Room Temperature: Selective Synthesis of δ‐Lactone

“…3‐Ethylidene‐6‐vinyltetrahydro‐2 H ‐pyran‐2‐one ( δ ‐lactone) generated via the palladium‐catalyzed telomerization of 1,3‐butadiene with CO 2 presents a series of synthetic applications in organic synthesis. For example, the hydrogenation, hydroamination, and polymerization of δ ‐lactone result in the generation of useful compounds. As the first successful example of the catalytic formation of a new C−C bond between CO 2 and an organic compound, the selective synthesis of δ ‐lactone from the telomerization of CO 2 and 1,3‐butadiene have received considerable attention.…”

Synthesis and Properties of Networks Based on Thiol‐ene Chemistry Using a CO2‐Based δ‐Lactone

“…For example, hydrogenation, alcoholysis and hydration with H 2 O were investigated to yield carboxylic acids, saturated lactones, diols, and hydroxy‐carboxylic acids, respectively. As for the polymerization of EVL, only a few reports are found with direct or indirect approaches, because it exhibits rather poor polymerizability toward conventional methods . The first successful polymerization of EVL was carried out through optimized radical polymerization with additives by Nozaki and coworkers .…”

“…The resultant polymers had high molecular weights up to 8.5 × 10 4 g mol −1 and high T g resulting from rigid backbone structure, which made them promising engineer plastics. Very recently, our group reported the synthesis of a trivinyl monomer from EVL, and topology‐controllable RAFT polymerization of the monomer was achieved . Dinjus reported the coupling reaction of EVL with dithiols to yield polymers, but only very preliminary results were obtained .…”

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found with direct or indirect approaches, because it exhibits rather poor polymerizability toward conventional methods. [17][18][19] The first successful polymerization of EVL was carried out through optimized radical polymerization with additives by Nozaki and coworkers. [17] The resultant polymers had high molecular weights up to 8.5 × 10 4 g mol −1 and high T g resulting from rigid backbone structure, which made them promising engineer plastics.

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“…Very recently, our group reported the synthesis of a trivinyl monomer from EVL, and topology-controllable RAFT poly merization of the monomer was achieved. [18] Dinjus reported the coupling reaction of EVL with dithiols to yield polymers, but only very preliminary results were obtained. [19] Still, there are very limited reports concerning the synthesis of polymers from EVL.Thiol-ene click chemistry has developed into a mature and diverse field of study in the past two decades.…”