Organocatalytic, Stereoselective, Cationic Reversible Addition–Fragmentation Chain-Transfer Polymerization of Vinyl Ethers

Abstract

Tacticity is a crucial factor affecting the properties of synthetic polymer materials. Here, we introduce a type of chiral organic Brønsted acid catalyst, 1,1′-bi-2-naphthol-derived N,N′-bis(triflyl)phosphoramidimidates (PADIs), for the cationic polymerization of vinyl ethers, which enables the development of the first organocatalytic, highly stereoselective, cationic reversible addition−fragmentation chain-transfer (RAFT) polymerization of vinyl ethers with a trithiocarbonate chain-transfer agent. This metal-free RAFT process could afford isotactic poly(vinyl ethers) with high stereoselectivity, controllable molecular mass, and narrow dispersity at low catalyst loadings (as low as 200 ppm). Moreover, the trithiocarbonate chain-end allows for chain extension to synthesize diblock copolymers comprising an isotactic poly(vinyl ether) block, by a mechanistic switching from stereoselective cationic RAFT polymerization to visible-light-regulated cationic and radical RAFT polymerization.

A continuous flow-through strategy to produce highly isotactic poly(isobutyl vinyl ether)viacationic polymerization

“…It should be noted that the current system utilizes the easily available TiCl 2 (OAr) 2 catalyst. It is expected that the utilization of chiral titanium catalysts 26 or chiral organic Brønsted acid catalysts [27][28][29] could lead to better control of the polymerization process.…”

“…26 Subsequently, this chemistry was expanded to the utilization of chiral organic Brønsted acid catalysts. [27][28][29] One limitation of these systems is the reverse correlation between the stereo-selectivity and monomer loading/concentration, which prevents their potential large-scale applications. Recently, a microreactor-based continuous flow technique has received a lot of attention for polymer synthesis due to its many superior characteristics.…”

“…26 Subsequently, this chemistry was expanded to the utilization of chiral organic Brønsted acid catalysts. 27–29…”

Hercynite silica sulfuric acid: a novel inorganic sulfurous solid acid catalyst for one-pot cascade organic transformations

“…In recent years, Brønsted acids have played a key role as catalysts or reagents in organic synthesis. 1–3 One of the famous classes of Brønsted acid catalysts is sulfurous acids. Besides, the sulfuric acid catalyst is the most important catalyst for organic reactions i.e.…”

Controllable synthesis and structural design of novel all-organic polymers toward high energy storage dielectrics

“…Polymers with various topologies, such as block, graft, gradient, star, brush, dendrimer and hyperbranched polymers could be synthesized by CRP technology. In addition, CRP is also a commonly used method to modify materials in order to adjust their chemical and physical properties (Figure 2) (Bagheri et al, 2021;Corrigan et al, 2021;Gong et al, 2021;Zhou et al, 2021;Antonopoulou et al, 2022;Zhang et al, 2022b;Li et al, 2022b;Zhou et al, 2022c;Corbin and Miyake, 2022;Dworakowska et al, 2022). ROMP is a relatively new research field in the preparation of polymer materials, which has all the characteristics of olefin metathesis reactions.…”