Journal of Molecular Catalysis A-Chemical, Vol.284, No.1-2, 77-84, 2008
Synthesis and evaluation of phosphine-N ligands in transition metal-catalysed C-C bond forming reactions
A series of phosphino-imine and the corresponding phosphino-amine P,NR ligands (R = alkyl, aryl) was synthesised from the commercially available starting material 2-(diphenylphosphino)benzaldehyde, including P,N bi-, tri- and tetradentate imine ligands, their secondary amine analogues, and also the methylated tertiary amine equivalents. As an extension, some P,NPPh2 and P,NPCy2 derivatives were also prepared from the same starting material. All of these ligands were successfully applied in catalytic reactions (Heck, cross-coupling and hydroformylation), and benchmarked against traditional ligands with satisfying results. While providing catalyst systems that were stable and generally acceptably active in comparison with the benchmarks, the Pd-ligand catalyst systems of this study were found to be especially active in Stille reactions. (C) 2008 Elsevier B.V. All rights reserved.