New stage in living cationic polymerization: An array of effective Lewis acid catalysts and fast living polymerization in seconds

Abstract

Our recent extensive research on Lewis acid catalysts with a weak base for the cationic polymerization of vinyl ethers led to unprecedented living reaction systems: fast living polymerization within 1-3 s; a wide choice of metal halides containing Al, Sn, Fe, Ti, Zr, Hf, Zn, Ga, In, Si, Ge, and Bi; and heterogeneously catalyzed living polymerization with Fe 2 O 3 . The use of added bases for the stabilization of the propagating carbocation and the appropriate selection of Lewis acid catalysts were crucial to the success of such new types of living polymerizations. In addition, the base-stabilized living polymerization allowed the quantitative synthesis of star-shaped polymers with a narrow molecular weight distribution via polymerlinking reactions and the precision synthesis and self-assembly of stimuli-responsive block copolymers.

Poly(mono/diethylene glycol n-tetradecyl ether vinyl ether)s with Various Molecular Weights as Phase Change Materials

“…As the number average molar mass increased, the crystallinity of the polymers and the number of crystallizable carbon atoms in the side chains of PC 14 E 1 VE and PC 14 E 2 VE were all reduced. The results were consistent with the previously reported literature [26,28]. For PC 14 E n VE, when n changed from 1 to 2, the number of crystallizable CH 2 groups N c were increased but the crystallinity of the polymers X c was decreased simultaneously.…”

“…These polymers PC 14 E n VEs (n = 1, 2) were measured using gel permeation chromatography (GPC) in THF at room temperature. The results are listed in In order to further analyze the impact of different molecular weights on the crystallization properties of polymers, the crystallinity of polymers and the number of crystallizable carbon atoms per side chain were calculated by Equations (1)- (3) [26,27]:…”

Controlled cationic copolymerization of benzaldehyde with isobutyl vinyl ether using base‐assisting system

“…[15][16][17] One of the methods that allows living cationic polymerization is the base-assisting reaction with a Lewis acid. [18][19][20] Recently, we have reported a series of greatly-improved living cationic polymerization systems of VE and St derivatives in the presence of an added Lewis base. [19][20][21] For example, it was demonstrated that various Lewis acids, including nonconventional ones, could act as living cationic polymerization catalysts in conjunction with an appropriate added Lewis base.…”

“…[18][19][20] Recently, we have reported a series of greatly-improved living cationic polymerization systems of VE and St derivatives in the presence of an added Lewis base. [19][20][21] For example, it was demonstrated that various Lewis acids, including nonconventional ones, could act as living cationic polymerization catalysts in conjunction with an appropriate added Lewis base. 22 Furthermore, this procedure permitted successful living polymerization of some monomers [23][24][25] that were previously considered to be challenging.…”

The first report of Lewis acid reagents in the intramolecular Rauhut–Currier reaction

“…Attempted cycloheptene formation also failed with both enolizable (dimethyl) and non-enolizable (diphenyl) substrates (Table 2, entries 5 and 6). Finally, an intermolecular Rauhut-Currier reaction with methyl vinyl ketone and tin tetrachloride lead only to products of polymerization (not shown); not surprising given the prevalence of cationic polymerization practices 10 . In pursuit of complex natural product-like intermediates for the generation of potentially bioactive compounds, we also explored the use of Lewis acids for Rauhut-Currier formation on a more complex substrate, 5 (see Supporting Information for synthesis of 5).…”