Synthesis, Structure, and Catalytic Activity of TiIV and ZrIV Complexes Derived from (R)‐2,2′‐Diamino‐1,1′‐binaphthyl‐Based N4‐Donor Ligands

Reaction of (R)-bis(pyrrol-2-ylmethyleneamino)-1,1′-binaphthyl (1H2) or (R)-N,N′-bis(pyridin-2-ylmethyl)-1,1′-binaphthyl-2,2′-diamine (2H2) with Zr(NMe2)4 (1 equiv.) gives chiral zirconium amides 1-Zr(NMe2)2·C7H8 (4·C7H8) or 2-Zr(NMe2)2 (6) in good yields, respectively. Under similar conditions, 1H2 reacts with Ti(NMe2)4 (1 equiv.) to give chiral titanium amide 1-Ti(NMe2)2·C6H6 (3·C6H6), whereas treatment of 2H2 with Ti(NMe2)4 (1 equiv.) leads to the isolation of bis(ligated) product (2)2-Ti·C7H8 (5·C7H8) in 74 % yield. All complexes were characterized by various spectroscopic techniques, elemental analysis, and X-ray diffraction analysis. Zirconium amides 4 and 6 are active catalysts for the asymmetric hydroamination/cyclization of aminoalkenes, and cyclic amines were obtained in good-to-excellent yields with moderate ee values (up to 59 %); titanium amides 2 and 5 were not active under the reaction conditions. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008)