Synthesis, conformation analysis and catalytic properties of chiral zirconium complexes containing etherfunctionalized Cp ligands

A novel series of chiral ligands was synthesized having a cyclopentadienyl (Cp) ring attached to an ether moiety. Four chiral monoCp zirconium derivat ives contain these ligands in a bidentate Cp/O coordination mode. Complexes 4d, 6d, and 7d bear an aryl group at the end of the ether chain. The racem ic complexes 3d and 4d show moderate activity for the polymerisation of eth ylene. Complexes 6d and 7d are enantiopure and were used as asymmetric Lewi s acid catalysts for the hydrocyanation of benzaldehyde. The negligible ena ntiomeric excess thereby is due to decomplexation of the weakly coordinated aryl ether side-chains during catalysis. (C) 1999 Elsevier Science S.A. Al l rights reserved.