Nature of the interaction between beta-substituents and the allyl moiety in (eta(3)-allyl)palladium complexes

beta -Substituted (eta (3)-allyl)palladium complexes are key-intermediates in synthetically important highly selective palladium-catalyzed transformat ions. Recently, several studies have appeared on the investigation of the e lectronic interactions occurring between beta -substituents and the allyl m oiety in these complexes. The nature of these electronic interactions was e xplored by MP2 and DFT calculations, and it has been studied by X-ray cryst allography, kinetic experiments and stoichiometric nucleophilic substitutio n of the beta -substituted (eta (3)-allyl)palladium complexes. These studie s revealed a new type of sigma-pi electronic interaction between the beta - substituents (Cl, OR, OAc and SiR3) and the allyl-metal moiety. It was foun d that these electronic interactions influence: (i) the structure of (eta ( 3)-allyl)palladium complexes; (ii) the kinetic and thermodynamic stability of these species; and (iii) the regiochemistry of the nucleophilic attack o n the allyl moiety.