Optically active poly(triphenylmethyl methacrylate) with one-handed helical conformation

Synthesis and structure determination of helical polymers

“…[1][2][3][4][5][6][7][8][9][10][11][12] The history of synthetic helical polymers with optical activity extends back to the 1960s when Pino and Lorenzi 13 investigated the structural and chiroptical properties of isotactic vinyl polymers prepared by the polymerization of a-olefins bearing optically active substituents. Although helical polyolefins are totally dynamic in nature and consist of short helical segments separated by frequently occurring helical reversals among disordered, random coil conformations, 14 this study was significant in the field of synthetic helical polymers, from which a number of helical polymers have been synthesized.On the basis of the pioneering studies by Nolte et al, 15 Okamoto et al 16 and Green et al, 17 the existing synthetic helical polymers that exhibit an optical activity solely because of their macromolecular helicity can be classified into two categories with respect to their helix inversion barriers, that is, static and dynamic helical polymers (Figure 1). 9,12 Optically active helical polymers, such as poly(triphenylmethyl methacrylate) (1), 16 poly(t-butyl isocyanide) (2) 15 and polychloral (3), 18 have a sufficiently high helix inversion barrier and belong to the family of static helical polymers.…”

“…On the basis of the pioneering studies by Nolte et al, 15 Okamoto et al 16 and Green et al, 17 the existing synthetic helical polymers that exhibit an optical activity solely because of their macromolecular helicity can be classified into two categories with respect to their helix inversion barriers, that is, static and dynamic helical polymers ( Figure 1). 9,12 Optically active helical polymers, such as poly(triphenylmethyl methacrylate) (1), 16 poly(t-butyl isocyanide) (2) 15 and polychloral (3), 18 have a sufficiently high helix inversion barrier and belong to the family of static helical polymers.…”

“…9,12 Optically active helical polymers, such as poly(triphenylmethyl methacrylate) (1), 16 poly(t-butyl isocyanide) (2) 15 and polychloral (3), 18 have a sufficiently high helix inversion barrier and belong to the family of static helical polymers. Therefore, these helical polymers with either a right-or left-handed helix can be prepared by the helix-sense-selective polymerization of the corresponding achiral monomers using chiral catalysts or initiators under kinetic control.…”

Transformation from preformed racemic helical poly(phenylacetylene)s to the enantioenriched helical polymers by chiral solvation, followed by removal of the chiral solvents

“…calcd. for C 17 Benzyl 2,6-dihydroxy-4-ethynylbenzoate (6). Triflation 45 of benzyl 2,4,6-trihydroxybenzoate and protection, 46 of hydroxyl groups were performed using modification of the respective literature methods.…”

“…[1][2][3][4] In particular, homochiral or enantioenriched helical polymers, the chirality of which is caused only by their helical conformation, will be useful for the design of optically active functional polymers and for the study of the relationship between chirality of helical structures and their performance. Effective approaches for obtaining these helical polymers include helix-sense-selective polymerization (HSSP) of achiral monomers in the presence of chiral catalysts [5][6][7][8][9][10][11] or in a chiral field [12][13][14] and the removal of a chiral side group from an optically active helical polymer bearing the chiral moiety. We have already succeeded in using the above methods to obtain poly(phenylacetylene)s with an induced kinetically stabilized helical bias.…”