Polymerization of Isoprene by Amidinate-Ligated Yttrium Catalysts.Unprecedented Switching of the Regio-and Stereoselectivity with an Alkyl Aluminum Compound

1 Results Search for catalysts which can control the regio- and stereoselectivity for olefin polymerization is a very important research subject.For the polymerization of isoprene,we have recently achieved,for the first time,the isospecific 3,4 polymerization by using a cationic rare earth metal alkyl catalyst bearing a silylene-linked cyclopentadieny-phosphido ligand1], and the cis-1,4 living polymerization by a bis(phosphinophenyl)amido-ligated rare earth metal catalyst2]. In addition to these ligan...