Preparation and application of polymer-supported pi-allylpalladium complexas a chiral catalyst in the asymmetric allylic alkylation

Chiral ferrocenylphosphine-imines A-D were synthesized and grafted to polys tyrene to afford polymeric ligands PA-PD. Ligands A-D and PA-PD were used a s ligands in the palladium-catalyzed asymmetric allylic alkylation. In the homogeneous reactions, the best result was obtained when the ligand A was u sed (99% yield and 82% ce). In the heterogeneous reactions, the highest ce value (73%) in the first run was obtained when PA was used as a ligand. Con sidering the enantioselectivity and reusability, the best result was obtain ed in the case of PC. The recycling of the polymer-supported pi -allylpalla dium catalyst gave unsatisfactory results: it can be reused three times wit h moderate enantioselectivities (60-70% ee). (C) 2001 Elsevier Science B.V. All rights reserved.