Process for the racemoselective synthesis of ansa-metallocenes

A process for the racemoselective preparation of ansa-metallocene complexes of the formula (I),

• which comprises reacting a ligand starting compound of the formula (II)
• with a transition metal compound of the formula (III)
• where
• R1, R1′ are identical or different and are each hydrogen or an organic radical having from 1 to 40 carbon atoms,
• R2, R2′ are identical or different and are each hydrogen or an organic radical having from 1 to 40 carbon atoms,
• R3, R3′ are identical or different and are each an organic radical having from 1 to 40 carbon atoms,
• T, T′ are identical or different and are each a divalent organic group which has from 1 to 40 carbon atoms and together with the cyclopentadienyl ring forms at least one further saturated or unsaturated, substituted or unsubstituted ring system which has a ring size of from 5 to 12 atoms, where T and T′ may contain the heteroatoms Si, Ge, N, P, As, Sb, O, S, Se or Te within the ring system fused to the cyclopentadienyl ring,
• A is a bridge consisting of a divalent atom or a divalent group,
• Z is a bridge consisting of a divalent atom or a divalent group,
• E is P, As or Sb,
• M1 is an element of group 4 of the Periodic Table of the Elements,
• M2 is an alkali metal, an alkaline earth metal or a magnesium monohalide fragment,
• p is 1 in the case of doubly positively charged metal ions or is 2 in the case of singly positively charged metal ions or metal ion fragments,
• the radicals X are identical or different and are each an organic or inorganic radical which can be substituted by a cyclopentadienyl anion,
• and
• LB is an uncharged Lewis-base ligand.