ANSA-METALLOCENE DERIVATIVES .19. STEREOSELECTIVITY AND REGIOSELECTIVITY OF CHIRAL, ALKYL-SUBSTITUTED ANSA-ZIRCONOCENE CATALYSTS IN METHYLALUMOXANE-ACTIVATED PROPENE POLYMERIZATION

Up to 94% yields of isotactic pentads are achieved in the polymerization of propene with the ansa‐zirconocene catalysts 1. It emerges that bulky substituents are decisive for the stereoselectivity, while α‐substituents are decisive for the regioselectivity. Moreover, α‐substituents favor the synthesis of long chains (Mw up to 9190). R1  tBu, iPr; R2  H. Me; μ‐X  Me2CCMe2, Me2Si. (Figure Presented.) Copyright © 1990 by VCH Verlagsgesellschaft mbH, Germany