Menthyl-functionalized chiral nonracemic bis(indenyl) complexes of zirconium, iron, nickel, and ruthenium

Optically active complexes of Zr, Fe, Ni, and nu containing the chiral, men thyl-substituted indenyl ligands (-)-3-menthyl-4,7-dimethylindene and (-)-2 -menthylindene are described. Metathetic reaction of the chiral main-group- metal salts of these indenyl systems with the appropriate starting material s of Zr, Fe, and Ni yielded the complexes (pR)(pR)-/(pR)(pS)(1-menthyl-4,7- dimethylindenyl)(2)ZrCl2 (4a/4b), (pR)-/(pS)-(cyclopentadienyl)(1-menthyl-4 ,7dimethylindenyl)ZrCl2 (5a/5b), (pR)(pR)-/(pR)(pS)-/(pS)(pS)-(1-menthyl(6a /6b/6c), (pR)(pR)-/(pR)(pS)-/(pS)(pS)-(1-menthyl-(7a/7b/7c), (+)-(2-menthyl indenyl)(2)Fe (8), and (-)-(2-menthylindenyl)(2)Ni (9). Ru(acac)(3) reacts with (-)-(2-menthylindenyl)lithium (3), yielding (-)-(2-menthylindenyl)(2)R u (10). Depending on the reaction conditions, compounds 4-7 were formed as mixtures of diastereomers with respect to the planar chirality of the inden yl ring system. The apparent diasteromeric excess varied between 13 and 50% de. The Fe, Ni, and Ru complexes were purified by chromatography via dried alumina under nitrogen. The structures of 4b and 8 were determined by sing le-crystal X-ray diffractometry.