Cationic palladium(II)-diphosphine complexes as catalysts for the carbonylation of alkenes to ketones

Cation palladium complexes of the type [(dppp)Pd(solvent) 2][X]2 2 [X=non or weakly coordinating anion; dppp=1,3-bis(diphenylphosphino)propane] are active catalysts for the carbonylaion to ketones, e.g., for the seletive formation of E-1,5-diphenylpent-l-en-3-one from styrene; in the presence of water and depending on the acidity conditions dimerisation to the much less catalytically active [(dppp)Pd(μ-OH)2 Pd(dppp)]X2 3 takes place, the structure of which was determined by X-ray crystallography.