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

✍ Scribed by Li Xiang; Haibin Song; Guofu Zi

• Publisher: John Wiley and Sons
• Year: 2008
• Tongue: English
• Weight: 211 KB
• Volume: 2008
• Category: Article
• ISSN: 1434-1948
• DOI: 10.1002/ejic.200701105

✦ Synopsis

Abstract

Reaction of (R)‐bis(pyrrol‐2‐ylmethyleneamino)‐1,1′‐binaphthyl (1H~2~) or (R)‐N,N′‐bis(pyridin‐2‐ylmethyl)‐1,1′‐binaphthyl‐2,2′‐diamine (2H~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, 1H~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 2H~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)