The cyclocopolymerization of (2S,3S)-2,3-butanediyl bis(4-vinylbenzoate) (1) with styrene was carried out in dry toluene at 40 degreesC in the presence of triethylaluminum (Et3Al), diethylaluminum chloride (Et2AlCl), and ethylaluminum dichloride (EtAlCl2), which played the role of Lewis acid capable of coordinating on carboxyl groups. After removal of the (2S,3S)-2,3-butanediyl units, the template-free polymer 3 exhibited an optical activity due to its main chain chirality. The specific rotations ([alpha](435), c 1.0, CHCl3) of polymers 3 prepared with alkylaluminum compound varied from -11.2 to -21.7 degrees, which was higher than those prepared without: alkylaluminum compound (-9.0 degrees). The specific rotation of polymer 3 increased with an increase in the acidity of the alkylaluminum compounds (i.e. Et3Al < Et2AlCl < EtAlCl2) and/or with an increase in the molar ratio of alkylaluminum compound to monomer 1. (C) 2001 Elsevier Science Ltd. All rights reserved.