Synthesis, Structure, and Catalytic Reactions of 1,2-Bis(indenyl)ethane-Derived Lanthanocenes

The synthesis and structure of meso-[ethylenebis(η5-indenyl)]ytterbium(III) bis(trimethylsilyl)amide (6) and the syntheses of rac- and meso-[[ethylenebis(η5-indenyl)]ytterbium(III) chloride][LiCl(Et2O)2] (4, 5) and rac- and meso-[ethylenebis(η5-indenyl)lutetium(III) chloride][LiCl(Et2O)2] (7, 8) are reported. The complexes are synthesized by the metathesis of dilithiated 1,2-bis(indenyl)ethane with either YbCl3 or LuCl3 in THF followed by solvent exchange with diethyl ether to give [[ethylenebis(η5-indenyl)]LnIII chloride][LiCl(Et2O)2] (Ln = Yb, Lu) in yields of 43% and 30%, respectively. In the Yb case, the major diastereomer formed is meso, while in the lutetium reaction, the rac diastereomer predominated. Complex 6 is synthesized by reaction of meso-[[ethylenebis(η5-indenyl)]ytterbium(III) chloride][LiCl(Et2O)2] with NaN(TMS)2; this material was characterized by X-ray diffraction. Complex 6 catalyzes the cyclic hydroamination of primary amino olefins in excellent yields.