Bis(diazaphospholidine) ligands for asymmetric hydroformylation: use of ESPHOS and derivatives based on ferrocene and diarylether backbones

A series of investigations have been completed on the use of the bis(diazaphospholidine) ligand ESPHOS in asymmetric hydroformylation. This study serves to confirm the optimum conditions for the use of this ligand. Two further ligands, based on ferrocene and biphenylether backbones, are also reported, but both give inferior results in hydroformylation in comparison with ESPHOS itself. The results from the hydroformylation reactions, and other studies, suggest that the ferrocene and biarylether systems are acting as monodonor ligands, rather than bidentate. (C) 2004 Elsevier Ltd. All rights reserved.