Stereoregular polymerization of cyclic vinyl ethers by transition metal catalysts

Abstract

2,3-Dihydrofuran(DHF) and 5-methyl-2,3-dihydrofuran(MDHF) were polymerized by various transition metal catalyst systems in toluene at $-78\,^\circ\!C$. The catalyst systems were consist of a basic tungsten catalyst, a stoichiometric tungsten catalyst, and a pretreated stoichiometric tungsten catalyst, i.e., $WCl_6,\;WCl_6: Et_2AlCl(1:4)$, and $WCl_6:Et_2AlCl$:Base(1:4:0.2), respectively. The higher polymerization yields of DHF and MDHF were obtained in the SW and the PSW catalyst system than in the basic catalyst system And the high molecular weight polymers were obtained by these catalyst systems. The stereochemical structures of the resulting.