Asymmetric Radical Polymerization of N-Phenylmethacrylamides

Stereospecific Living Radical Polymerization: Dual Control of Chain Length and Tacticity for Precision Polymer Synthesis

“…However, the polymers of its derivatives, such as N-(2,6-diethylphenyl)methacrylamide (BM-34), prepared in chiral menthols were less soluble and showed optical activities, suggesting the higher stereospecificity though the details are not clear. 245 In sharp contrast to the above-mentioned vinylidene monomers with an R-methyl group, radical polymerization of the monosubstituted vinyl derivatives has a greater tendency to afford almost atactic polymers regardless of the monomer structure and polymerization temperature (Table 3). 218,[246][247][248][249][250] As the substituents in the acrylate become bulkier, the syndiotacticity of the obtained polymers slightly increases contrary to the polymerization of the methacrylates, probably due to the steric repulsion in the antistaggered gauche conformations of the planar polymer chain ( Figure 15).…”

“…N -Phenylmethacrylamide (BM- 33 ) was polymerized into rather syndiotactic polymers regardless of the polymerization condition ( mm / mr / rr = 8/39/53). However, the polymers of its derivatives, such as N -(2,6-diethylphenyl)methacrylamide (BM- 34 ), prepared in chiral menthols were less soluble and showed optical activities, suggesting the higher stereospecificity though the details are not clear …”

Helical Polymers: Synthesis, Structures, and Functions

“…The radical polymerization of bulky N -triphenylmethyl methacrylamides ( 15  18 , Chart ) in the presence of (+)- and (−)-menthol also produces highly isotactic, optically active helical polymers, although the helix-sense excess of the polymers seems lower than that of PTrMA . In the case of the radical polymerization of N -phenyl methacrylamides in l - or d -menthol, only the 2,6-disubstituted derivatives, such as 19 , produce optically active polymers . On the other hand, the anionic polymerization of N -triphenylmethyl methacrylamides with n -butyllithium does not proceed due to the presence of its acidic NH proton.…”

“…54 In the case of the radical polymerization of N-phenyl methacrylamides in L-or D-menthol, only the 2,6-disubstituted derivatives, such as 19, produce optically active polymers. 55 On the other hand, the anionic polymerization of N-triphenylmethyl methacrylamides with n-butyllithium does not proceed due to the presence of its acidic NH proton. However, the chiral anionic initiator system consisting of the organozincates with chiral additives, such as n-Bu 4 ZnLi 2 /2,3,4,6-tetra-O-acetyl-R-Dgalactopyranosyl bromide, allows the helix-sense-selective anionic polymerization of the bulky methacrylamide 16 to afford the highly isotactic, optically active helical polymer.…”

Asymmetric Polymerization

“…Optically active, single -handed helical poly -149 and poly -158h and their copolymers with methacrylate blocks were obtained in almost quantitative yield by using 164 as a catalyst. Radical polymerization of methacrylamides 159 [218] , 160 [219] , and 161 [220] was carried out in ( − ) -menthol as a solvent to afford optically active, highly isotactic helical polymers in good yield.…”