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

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.