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DFT Computational Study of the Mechanism of Allyl Chloride Carbonylation Catalyzed by Palladium Complexes

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journal contribution
posted on 25.04.2005, 00:00 by M. Angels Carvajal, Gian Pietro Miscione, Juan J. Novoa, Andrea Bottoni
A theoretical DFT (B3LYP) investigation on the carbonylation reaction of allyl chloride catalyzed by Cl2Pd(PH3)2 is discussed. The computational results show the following. (i) The favored reaction channel leading to the β,γ-unsaturated acyl chloride product is a direct attack of the chlorine atom on the metal (σ pathway). (ii) The carbonylation pathway involving the formation of π-allyl complexes is highly disfavored. (iii) In the π complexes the ligand is not η3-coordinated to the metal, as usually assumed, but η2-coordinated. (iv) The presence of a favored σ pathway seems to be a common feature of this class of reactions (i.e. metal-catalyzed carbonylation of allyl halides). (v) The Cl2Pd(CO)2 complex, which forms from Cl2Pd(PH3)2, can behave as an “active” catalytic species. In the presence of high CO pressures, it initiates an alternative pathway that can be competitive with the main σ pathway.