Polymerization of 4-Methylene-1,3-dioxolane Derivatives

摘要

The 4-methylene-1,3-dioxolane derivatives, 2-[(2-methoxyethoxy)methyl]-4-methylene-1,3-diox olane (4a), 4-methylene-2-phenyl-1,3-dioxolane (4b), 4-methylene-2-(p-methoxyphenyl)-1,3-dioxolane (4c), 4-methylene-2-[p-(2-methoxyethoxy)phenyl]-1,3-di oxolane (4d) were prepared by acetalization, followed by dehydrochlorination with potassium tert-butoxide (t-BuOK). They were readily polymerized with boron trifluoride and tungsten hexachloride. Monomer 4a underwent 70% ring-opening polymerization with WCl6, whereas monomers 4b and 4c polymerized with quantitative ring-opening to form poly(keto ether)s. Especially 4d underwent Claisen-type isomerization to afford 2-[4-(2-methoxyethoxy)phenyl]-3(2H)-dihydrofuran one in the presence of WCl6. Acid catalyzed mechanisms were suggested for the behaviors of polymerization and isomerization of 4-methylene-1,3-dioxolane derivatives with BF3 and WCl6 catalyst.