Syntheses and reactions of fulvene-derived substituted aminoalkyl-Cp and phosphinoalkyl-Cp-Group 4 metal complexes

Abstract

6-Dialkylaminofulvenes add a variety of RLi reagents to form (dialkylaminoalkyl)cyclopentadienides [ C 5 H 4 C R 1 R N R ′ 2 ] Li , which exhibit oligomeric chain structures in the solid state. Transmetallation yields the corresponding titanocene or zirconocene derivatives that often show interesting intramolecular CH activation reactions. Phosphide anion addition to 6-alkyl-fulvenes yields the analogous phosphinoalkyl-Cp reagents and subsequently their Group 4 metallocene complexes. Deprotonation of 6-dialkylamino-6-alkylfulvenes generates enamino-substituted Cp-ligands. Their metal complexes undergo intramolecular Mannich reactions to yield C 3-bridged ansa-metallocene products. Treatment of 6-dimethylaminofulvene with LiNHAr reagents leads to amine exchange and opens a synthetic route to “CpCN”MX 2 “constrained geometry” catalysts. LiNHR addition to some 6-alkylfulvenes represents an alternative entry to this important class of compounds. The corresponding “CpCP”MX 2 systems are derived from the analogous LiPHR addition reaction. Many typical reactions of the new fulvene-derived metal complexes are presented and discussed.