Patent ID: 7098354

Claim:
A process for the diastereoselective synthesis of rac-diorganosilylbis(2-methylbenzo[e]indenyl)zirconium compounds of the formula I, which comprises the following steps: a) reaction of a compound of the formula II with a zirconium bisphenoxide complex of the formula III to form the ansa-zirconocene bisphenoxide complex of the formula IV, b) replacement of the phenoxide groups of IV by X using suitable replacement reagents to give the compound of the formula I; where the substituents X can be identical or different and are each F, Cl, Br, I, or linear, cyclic or branched C 1-10 -alkyl; and the substituents R can be identical or different and are each linear, cyclic or branched C 1-10 -alkyl or C 6-10 -aryl; and LB is a suitable Lewis base, and M 1 and M 2 are monovalent positive alkali metal ions or M 1 and M 2 together represent a divalent positive alkaline earth metal ion.