Lanthanide and group 4 metal complexes with new chiral biaryl-based NNO-donor ligands

A new series of lanthanide and group 4 metal complexes have been prepared from the reactions between Ln[N(SiMe3)(2)](3) or M(NMe2)(4) and chiral ligands, (R)-2-(pyrrol-2-ylmethyleneamino)2'-methoxy-1,1'-binaphthyl (1H), (S)-5,5',6,6',7,7',8,8'-octahydro-2-(pyrrol-2-ylmethyleneamino)2'-methoxy-1,1'-binaphthyl (2H) and (R)-2-(pyrrol-2-ylmethyleneamino)-2'-methoxy-6,6'-dimethyl-1,1'-biphenyl (3H). The steric effect of the ligand coupled with the size effect of the ions plays an important role in the formation of the lanthanide complexes. For example, treatment of 1H with 1 equiv of Ln[N(SiMe3)(2)](3) (Ln = Y, Yb) in toluene gives the tris-ligated complexes, (1)(3)Y center dot C7H8 (5 center dot C7H8) and (1)(3)Yb center dot 2C(7)H(8) (6 center dot 2C(7)H(8)) in good yields; reaction of 2H with 1 equiv of Sm[N(SiMe3)(2)](3) also gives the tris-ligated product (2)(3)Sm (7), while treatment of 2H with 1 equiv of Ln[N(SiMe3)(2)](3) (Ln = Y, Yb) leads to the isolation of the bis-ligated organolanthanide amides (2)(2)LnN(SiMe3)(2)center dot 2C(6)H(6) (Ln = Y (8 center dot 2C(6)H(6)), Yb (9 center dot 2C(6)H(6))) in good yields. Reaction of 1H, 2H or 3H with 1 equiv of M( NMe2) 4 gives, after recrystallization from a toluene or benzene solution, the chiral bis-ligated titanium amides (1)(2)Ti(NMe2)(2)center dot 0.75C(7)H(8) (10 center dot 0.75C(7)H(8)), (2)(2)Ti(NMe2)(2) (12), (3)(2)Ti(NMe2)(2)center dot C6H6 (14 center dot C6H6), and zirconium amides (1)(2)Zr(NMe2)(2)center dot C7H8 (11 center dot C7H8), (2)(2)Zr(NMe2)(2) (13), (3)(2)Zr(NMe2)(2)center dot C6H6 (15 center dot C6H6), in good yields, respectively. Treatment of Zr( NMe2) 4 with 1 equiv of (R)-2-(pyrrol-2-ylmethylamino)2'-methoxy-1,1'-binaphthyl(4H(2)), which was prepared from the reduction of 1H with an excess of NaBH4 in a solvent mixture of MeOH and toluene (1 : 1) at 50 degrees C, gives the trinuclear complex [(R)-2-O-C20H12-2'-(NCH2C4H3)](2)Zr-3(NMe2)(6)center dot 2C(7)H(8) (16 center dot 2C(7)H(8)) in 65% yield. Organolanthanide amides and zirconium amides are active catalysts for asymmetric hydroamination/cyclization of aminoalkenes, affording cyclic amines in moderate to good yields with moderate ee values, while the titanium amides are not. During the course of the catalytic reaction, 8 is decomposed leading to the isolation of (2)(3)Y center dot C7H8 (17 center dot C7H8) in 35% yield from a toluene solution. The organolanthanide amides are also active catalysts for ring-opening polymerization of rac-lactide, giving isotactic-rich polylactides. All compounds have been characterized by various spectroscopic techniques, and elemental analyses. The solid-state structures of compounds 2H, 3H, 5 - 11, and 13 - 17 have further been confirmed by X-ray diffraction analyses.