Stereochemistry of the copolymerization of carbon dioxide with optically active phenylepoxyethane

The stereochemistry of the copolymerization of optically active phenylepoxyethane (5) with carbon dioxide using a diethylzinc/water system as catalyst was investigated. The optically active copolymer, poly(oxycarbonyloxy‐2‐phenylethylene) (1), was hydrolyzed and the oxy‐2‐phenylethylene unit was isolated in the form of 1,2‐bis(trimethylsilyloxy)‐1‐phenylethane (3). The determination of the optical activity of this ether led to the conclusion that the ring opening of 5 takes place predominantly at the methineoxygen linkage accompanying an inversion in the copolymerization. This fact is in sharp contrast with the stereochemistry of the copolymerization of carbon dioxide with 1,2‐epoxypropane in which the ring opening takes place at the methylene‐oxygen linkage.