Synthesis, structure, and catalytic activity of binuclear lanthanide complexes with chiral NOBIN-based NNO ligands

Two new amido binuclear complexes {(1)YN(SiMe3)2}2 · C7H8 (3 · C7H8) and {(2)SmN(SiMe3)2}2 · C6H14 (4 · C6H14) have been readily prepared in good yields by amine elimination reaction between Ln[N(SiMe3)2]3 (Ln = Sm, Y) and chiral NNO ligands, (S)-2-(pyridin-2-ylmethylamino)-2′-hydroxy-1,1′-binaphthyl (1H2) and (S)-5,5′,6,6′,7,7′,8,8′-octahydro-2-(pyrrol-2-ylmethyleneamino)-2′-hydroxy-1,1′-binaphthyl (2H2), respectively. They both have been characterized by various spectroscopic techniques, elemental analyses, and X-ray diffraction analyses. They are active catalysts for asymmetric hydroamination/cyclization of aminoalkenes and ring-opening polymerization of rac-lactide, affording cyclic amines in excellent conversions with moderate ee values and isotactic-rich polylactides, respectively.

Graphical abstractTwo new binuclear lanthanide amides with chiral NNO ligands have been prepared. They are active catalysts for the asymmetric hydroamination/cyclization of aminoalkenes and the ring-opening polymerization of rac-lactide, affording cyclic amines in excellent conversions with moderate ee values and isotactic-rich polylactides, respectively.Figure optionsDownload full-size imageDownload as PowerPoint slide