Diastereo- and enantioselective syntheses of ansa-metallocenes from metal halide complexes with tropos biphenol and atropos binaphthol ethers

A diastereo- and enantioselective route to synthesize ethylene-bis(4,5,6,7-tetrahydro-1-indenyl)-titanium and -zirconium dichlorides is described using titanium trichloride or zirconium tetrachloride complexes with tropos (chirally flexible) biphenol and atropos (chirally rigid) binaphthol ethers.