PREPARATION OF 1,1'-BINAPHTHYL-2,2'-DIYL BRIDGED ANSA-BIS(ANNULATED-CYCLOPENTADIENYL)TITANIUM AND ANSA-BIS(ANNULATED-CYCLOPENTADIENYL)ZIRCONIUM DICHLORIDE COMPLEXES

The coupling of enantiomerically enriched 2,2'-dilithio-1,1'-binaphthy l with various annulated cyclopentenones or 2-indanone proves to be a facile route for the preparation of a series of annulated bis(cyclopen tadienes) or bis(indenes) bridged at a symmetrical cyclopentadienyl po sition. The six- or seven-membered annulated bis(tetrahydroindene) 6 o r bis(hexahydroazulene) 7 ligands could readily be converted to titani um or zirconium dichloride complexes. Owing to the symmetry of the lig ands, only a single C-2-symmetrical isomer of the metallocene dichlori de could form. Although the faces of the cyclopentadienyl moieties are homotopic, the chiral bridge enforces a chiral conformation of the me tallocene complexes. The bis(indenyl) 5 or five-membered annulated bis (tetrahydropentalene) 8 ligands could not be metalated. Unbridged 2-me thyl and 2-phenyl substituted tetrahydropentalenes 27 and 28 were prep ared and could readily be converted to titanium dichloride complexes.