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Chirality induction in cyclopolymerization, 5 . Template effect of chiral acyclic 1,2‐glycols on the cyclo‐copolymerizations of ( S )‐1,2‐propanediyl and (2 S ,3 S )‐2,3‐butanediyl bis(4‐vinylbenzoate)s with styrene
Author(s) -
Kakuchi Toyoji,
Haba Osamu,
Uesaka Takahiro,
Yamauchi Yukio,
Obata Makoto,
Morimoto Yasushi,
Yokota Kazuaki
Publication year - 1996
Publication title -
macromolecular chemistry and physics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.57
H-Index - 112
eISSN - 1521-3935
pISSN - 1022-1352
DOI - 10.1002/macp.1996.021970926
Subject(s) - chirality (physics) , chemistry , styrene , vicinal , toluene , reactivity (psychology) , monomer , stereochemistry , asymmetric induction , copolymer , polymer chemistry , enantioselective synthesis , polymer , organic chemistry , catalysis , physics , medicine , chiral symmetry breaking , alternative medicine , pathology , quantum mechanics , nambu–jona lasinio model , quark
The copolymerizations of ( S )‐1,2‐propanediyl and (2 S ,3 S )‐2,3‐butanediyl bis(4‐vinyl‐benzoate)s ( 2a and 2b ) (M 1 ) with styrene (M 2 ) were carried out using 2,2′‐azoisobutyronitrile in toluene at 60 °C. For the cyclocopolymer 3 , the extent of cyclization of 3b is higher than that of 3a . The monomer reactivity ratios are r 1 = 8.34 and r 2 = 0.27 for 2a and r 1 = 6.82 and r 2 = 0.19 for 2b . The specific rotation ([α] 435 23in deg · dm −1 · g −1 · cm 3 c = 1.0 g · dL −1 ; CHCl 3 ) changes from +230 to +176 for 3a and from +319 to +150 for 3b . After removing the chiral templates, the resulting poly[(methyl 4‐vinylbenzoate)‐ co ‐styrene]s showed a specific rotation ([α] 435 23in deg · dm −1 · g −1 · cm 3 c = 1.0 g · dL −1 ; CHCl 3 ) of −2 for 4a and of −8 for 4b , indicating that the (2 S ,3 S )‐2,3‐butanediyl template shows a higher ability to cause asymmetric induction by comparison with the ( S )‐1,2‐propanediyl one. A split Cotton effect due to the positive chirality was observed in the CD spectrum of 2 and the reversed one for 4 . According to the CD exciton chirality method, the clockwise‐twist of two 4‐vinylbenzoate for 2 transmitted its chirality to 4 in which two 4‐vinylbenzoyl groups are twisted counterclockwise, i. e., an ( R , R )‐configuration of vicinal (methyl 4‐vinylbenzoate) units in the main chain.