Asymmetric‐induction polymerization of β‐vinylacrylates

Abstract

Optically active polymers of methyl, ethyl, n-butyl, and tert-butyl P-vinylacrylates were synthesized b y using optically active catalyst systems such as n-Bulilsodium I-menthoxide and n-Bulilsodium d-bornoxide. The optically active alkoxides were found to be even more efficient cocatalysts for the asymmetric-induced polymerization than were the corresponding ethers.The polymers obtained were characterized from their optical rotatory dispersion curves and infrared absorption spectra. ZUSAMMENFASSUNG:Mit Hilfe von optisch aktiven Katalysatorsystemen wie z. B. mit n-Butyllithiumll-Mentholnatrium und n-Butyllithiumld-Borneolnatrium wurden die optisch aktiven polymeren Methyl-, Athyl-, n-Butyl-und tert-Butyl-P-vinylacrylsaureester hergestellt. Es wurde gefunden, da13 die optisch aktiven Alkoxide fiir die asymmetrisch induzierte Polymerisation wirksamere Cokatalysatoren sind als die entsprechenden Ather.Die dargestellten Polymeren wurden durch die optischen Rotationsdispersionskurven und die Infrarotabsorptionsspektra charakterisiert.

Asymmetric Polymerization

“…They demonstrated that the polymer's optical activity is based on main-chain chirality by ozonolyzing the polymers to give an optically active diacid, 11; optical purity of the resulting acid obtained from the polymers of 7 and 8 is reported to be 0.4-6% (Scheme 2).6 Afterward, the relationship between the structure of the catalyst consisting of titanium and aluminum used for 1,3-pentadiene polymerization and asymmetric inductivity was reexamined by This type of polymerization of achiral 1,3-diene monomers has also been done by other researchers. [49][50][51] Asymmetric induction to main-chain chiral centers has also been observed in the radical polymerization of sorbates having an optically active ester group52'53 and 1,3-butadiene-l-carboxylic acid complexed with optically active amines. [54][55][56] Asymmetric synthesis polymerization of 1,3-dienes with solid matrices has been reported.57 '58 This was first attained by Farina and co-workers: they obtained an optically active polymer with isotactic trans-10 by 7-ray irradiation polymerization of trans-1,3-pentadiene included in an optically active (R)-(-)-trans-antitrans-anti-trans-perhydrotriphenylene (12) matrix.59 '60 Deoxyapocholic61'62 and apocholic63'64 acids (13 and 14) are also effective as an optically active matrix.…”

Optically Active Polycarbonates: Asymmetric Alternating Copolymerization of Cyclohexene Oxide and Carbon Dioxide

“…Chiral catalysts create new chiral centers in the main chain of the resulting polymers with control of the absolute configuration. Precedents for such a methodology are ring-opening polymerization of epoxide or episulfide, cyclopolymerization of α,ω-dienes, polymerization of unsymmetrical dienes or cyclic olefins, and alternating copolymerization of α-olefins with carbon monoxide. , Here, we report the first example of asymmetric synthesis copolymerization of meso epoxide 1 with CO 2 , initiated by a chiral Zn catalyst . Since the ring-opening of epoxides involves configurational inversion at one of the two chiral carbons, meso epoxides 1 , achiral by nature, produce copolymers 2 , including chiral diol units −O−CHR−CHR−O−.…”

Anionic copolymerization of isocyanates with ketenes

“…This was followed by aromatic peaks at 1600, 1500, and 1450 em-', a strong absorption from 1320-1100 cm-l, and peaks a t 770 and 700 em-', characteristic of monosubstituted aromatic compounds. The NMR spectrum showed a single, very broad peak from 7.6 to 6.0 ppm (6); the maximum was a t 7.2 ppm.…”

“…No peak was observed a t 1680 or a t 1710 cm-', characteristic of polyketone or polyacetal, respectively. ** The NMR spectrum showed a very broad singlet with the maximum a t 7.2 ppm (6) and an extremely broad ethyl envelope beginning at 2.7 ppm and extending well past the peak of the TMS standard a t 0 ppm.…”

“…Phenylmethylketene has been copolymerized similarly with benzaldehyde. 6 Although dimethylketene can homopolymerize to form polyacctal, polyketone, or polyester,'^* all ketene copolymers were of the polyester structure, as illustrated for poly(phenylmethy1ketene-co-benzaldehyde (I) :6 I By means of anionic systems isocyanates also have been copolymerized with a number of aldehydes, including c h l~r a l ,~* l~ formaldehyde, lo n-butyr-aldehyde, lo and B-cyanopropionaldehyde. Polymeric methylidene carbanilates (substituted polyurethanes) were formed, as illustrated for poly-(phenyl isocyanate-co-chloral) (11) :9…”