CHIRALITY INDUCTION IN CYCLOPOLYMERIZATION .7. ASYMMETRIC CYCLO-COPOLYMERIZATION OF 1,2 ISOPROPYLIDENE-3,4-BIS-O-(4-VINYLBENZOYL)-D-IDITOL WITH STYRENE/

isopropylidene-3,4-bis-O-(4-vinylbenzoyl)-D-iditol (2a) was cyclocopol ymerized with styrene to yield copolymer 3a, essentially consisting of cyclic repeating and styrene units. In order to confirm the asymmetri c induction in 3a, removal of the template from 3a was carried out, an d then the resulting hydrolyzed copolymer was treated with diazomethan e leading to poly[(methyl 4-vinylbenzoate)co-styrene] (4a). Copolymer 3a showed a positive specific relation, whereas a negative rotation wa s observed for 4a. The CD spectrum of 2a exhibited a positive Cotton e ffect at 287.6 nm and a negative effect at 263.4 nm. According to the exciton chirality method, 2a had a positive chirality and its benzoate chromophores, the two 4-vinylbenzoyl groups, were twisted clockwise. In contrast, the CD spectrum of 4a (2a/St = 0.24/0.76) showed a split Cotton effect with a negative effect at 255.0 nm and a positive effect at 235.0 nm. These results indicated that 4a had a negative chirality in which two 4-vinylbenzoyl groups were twisted counterclockwise, i.e ., the vicinal (methyl 4-vinylbenzoate) groups in the main chain had a n R,R-configuration. The ability of 2a for chirality induction as comp ared with that of other monomers, opropylidene-3,4-bis-O-(4-vinylbenzo yl)-D-mannitol (2b) and opropylidene-3,4-bis-O-(4-vinylbenzoyl)-D-gluc itol (2c).