New syntheses of ansa-metallocenes or unbridged substituted metallocenes by the respective reductive dimerization of fulvenes with Group 4 metal divalent halides …

JJ Eisch, FA Owuor, X Shi

Index: Eisch, John J.; Owuor, Fredrick A.; Shi, Xian Polyhedron, 2005 , vol. 24, # 11 p. 1325 - 1339

Full Text: HTML

Citation Number: 20

Abstract

Two unprecedented syntheses of Group 4 metallocenes from 6-substituted fulvenes have been discovered and developed into high-yielding processes. In the first route the di-n- butylmetal dichlorides of Ti, Zr and Hf are generated in toluene suspensions of LiCl at− 78° C from the metal tetrachlorides and 2 equiv. of n-butyllithium. Bringing the Bun2MCl2 to 25° C and then heating at reflux for several hours gave complete conversion to slurries of ...