Palladium-catalyzed carbon-carbon bond formation from (η⁶-chloroarene)Cr(CO)₃ complexes an example of bimetallic activation in homogeneous catalysis

The effect of the coordination of a tricarbonylchromium moiety to the aromatic ring of aryl chlorides in the activation toward oxidative addition of the CCl bond to zerovalent palladium complexes is described. It presents an overview of catalytic reactions and fundamental investigations with the aim to rationalizing the role of the Cr(CO)₃ moiety on some of the elementary steps of these reactions. This topic is divided according to the nature of the catalytic reactions involving the tricarbonyl (chloroarene) chromium complexes. Firstly, the results obtained during the cross-coupling reaction with nucleophilic reagents (copper acetylides, organostannanes) and the catalytic Heck olefination reaction are presented. Then, several carbonylation processes, such as hydrocarbonylation into aldehydes, mono- and double carbonylation into amides and α-oxo-amides, and finally alkoxycarbonylation into esters, are discussed. Particular attention is given to the catalytic and stoichiometric aspects of this last reaction.