Novel Effective Racemoselective Method for the Synthesis of ansa-Zirconocenes and Its Use for the Preparation of C₂-Symmetric Complexes Based on 2-Methyl-4-aryltetrahydro(s)indacene as Catalysts for Isotactic Propylene Polymerization and Ethylene–Propylene Copolymerization

A general and effective method for the racemoselective synthesis of bis-indenyl-type ansa-zirconocenes was proposed and successfully applied for the synthesis of several C₂-symmetric ansa-zirconocenes based on 2-methyl-4-aryltetrahydro-s-indacene. This new racemoselective method relies on ZrCl₃NH-tert-Bu as a key reagent. The formation of racemic products was confirmed by NMR studies and single-crystal X-ray diffraction. The novel complexes are potent catalysts for isotactic propylene polymerization and ethylene–propylene copolymerization.