Carbonylation of Ethene in Methanol Catalysed by Cationic Phosphine Complexes of Pd(II): from Polyketones to Monocarbonylated Products

This review article describes the advances on the carbonylation of ethene in methanol since the discovery of highly active cationic cis-chelating diphosphine-Pd(II) catalysts for the production of perfectly alternating high molecular weight polyketones, which led to the recent development of efficient catalysts for the synthesis of monocarbonylated products. After dealing with the activation of the catalyst precursor and with mechanistic aspects of the catalytic cycles, the influence of the operating conditions, the nature of the counter anion, the acidity of the reaction medium and the nature of the ligand on both the rate and the selectivity is delineated. In particular, it is shown that the catalytic activity can be finely tuned by varying the electronic, bite angle and steric bulk properties of the ligand and that, within a series of related ligands, the selectivity mainly depends on the steric bulk.