Optically active polymers: Some new results and remarks on the asymmetric polymerization of benzofuran

Abstract

AbstractThe conditions for obtaining polybenzofuran with high optical activity using the system AlCl3/β‐phenylalanine as catalyst are described. The behaviour of the asymmetric synthesis is examined during the course of the reaction, and the relationship between the rotatory power and the degree of polymerization of the polymer is discussed.A polymerization mechanism is proposed, which comprises a process of asymmetric growth (in which a counterion containign phenylalanine conditions the configuration of each monomeric unit) and a racemizing termination process. This hypothesis explains the experimental facts, particularly the constancy of [α] with varying [η] and the progressive deterioration of the asymmetric synthesis during the polymerization.