Synthesis, Structure, and Catalytic Activity of Ti IV and Zr IV Complexes Derived from ( R )‐2,2′‐Diamino‐1,1′‐binaphthyl‐Based N 4 ‐Donor Ligands

Reaction of ( R )‐bis(pyrrol‐2‐ylmethyleneamino)‐1,1′‐binaphthyl ( 1 H 2 ) or ( R )‐ N , N′ ‐bis(pyridin‐2‐ylmethyl)‐1,1′‐binaphthyl‐2,2′‐diamine ( 2 H 2 ) with Zr(NMe 2 ) 4 (1 equiv.) gives chiral zirconium amides 1 ‐Zr(NMe 2 ) 2 · C 7 H 8 ( 4· C 7 H 8 ) or 2 ‐Zr(NMe 2 ) 2 ( 6 ) in good yields, respectively. Under similar conditions, 1 H 2 reacts with Ti(NMe 2 ) 4 (1 equiv.) to give chiral titanium amide 1 ‐Ti(NMe 2 ) 2 · C 6 H 6 ( 3· C 6 H 6 ), whereas treatment of 2 H 2 with Ti(NMe 2 ) 4 (1 equiv.) leads to the isolation of bis(ligated) product ( 2 ) 2 ‐Ti · C 7 H 8 ( 5· C 7 H 8 ) 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)