Chirality induction in cyclocopolymerization of bis(p-vinylbenzoate)s of carbohydrates with styrene: Chiroptical study of resulting polymer by exciton chirality method

Three bis(p-vinylbenzoate) monomers, 2,3-O-isopropylidene-1,4-bis-O-(p-vinylbenzoyl)-L-threitol (BIT), methyl 4,6-O-isopropylidene-2,3-bis-O-(p-vinylbenzoyl)-α,D -glucopyranoside (BIG), and 1,2:5,6-di-O-isopropylidene-3,4-bis-O(p-vinylbenzoyl)-D-mannitol (BIM), were prepared and cyclocopolymerized with styrene. The resulting copolymers were hydrolyzed with KOH to remove the chiral template, and treated with diazomethane to give poly[(methyl p-vinylbenzoate)-co-styrene] [poly(MVB-co-St)]. All the poly(MVB-co-St) had a specific rotation and their CD spectra exhibit a split Cotton effect. Poly(MVB-co-St) derived from poly(BIT-co-St) showed a positive Cotton effect at 255 nm and a negative one at 235 nm. According to the exciton chirality method, poly(MVB-co-St) possessed negative chirality, and the stereochemistry of the carbon atom attached to the 4-benzoyl group had the S configuration. The absolute configuration of poly(MVB-co-St) was determined as R for the BIG/St system and S for the BIM/St system. © 1995 Wiley-Liss, Inc.