| Metallocene-based Group 3 metal complexes; lanthanocenes, have intrinsic problems for use as a universal catalysis. For example, preparations of most complexes are complicated, and most lanthanocenes are extremely sensitive to air and water and have structural limitation on variation.; The first application of non-metallocene-based Group 3 metal catalysts to intramolecular aminoalkene cyclizations has been achieved. Simple amido lanthanide complexes of the type Ln[N(TMS)2]3 (Ln = Y, Nd) have been found to be competent catalysts for this reaction, which have similar or superior activity in cyclization including diastereoselectivity to the lanthanocenes. Modification of the metal center in Ln[N(TMS)2 ]3 (Ln = Y, Nd, La) has been readily achieved by amine elimination in the presence of hindered chelating diamines, bis(thiophosphinic) amines, or bis(thioenamides) in situ, to provide new Group 3 amido chelates. These complexes have shown remarkably improved catalytic activities and stereoselectivities [e.g., 33:1 (trans/cis)] in the cyclization of 2-aminohex-5-ene. An X-ray crystallographic structure of one of the bis(thiophosphinic amide)-based Group 3 metal complexes has been defined. Chiral lanthanide complexes have been implemented for enantioselective hydroamination reactions. The C2 symmetric catalysts exhibit good enantioselectivity in the cyclization of 1-amino-2,2-dimethylpent-5-ene, as high as 66% enantiomeric excess at 10°C.; These non-metallocene-based Group 3 metal complexes have shown superiority in terms of preparation, thermal stability, and catalytic activity over lanthanocenes in the hydroamination of aminoalkenes. In addition, the amido complexes should allow for a variety of ligand derivatives. |
