Understanding palladium-mediated transformationsaerobic c-h alkenylation of arenes via metal-ligand cooperation and reactions with carbene precursors

Resumo

One of the main goals of research in Chemistry nowadays is to achieve more efficient chemical syntheses. The work in this thesis is intended to contribute to this goal by improving the efficiency of palladium-catalyzed processes. With this aim, the research is focused on the use of novel catalysts in combination with mechanistic studies of the steps that constitute the catalytic cycles. Two different types of catalytic processes were chosen: cross-coupling reactions of arenes that involve C-H activation, and cross-coupling processes that use carbene precursors. Both are attractive reactions to achieve molecular complexity in a reduced number of synthetic steps: The first one because no prefunctionalization of the arenes, the available raw materials, is needed; the second one because the formation of more than one C-C or C-X bonds occurs in just one synthetic step. The analysis of catalytic and stoichiometric reactions along with kinetic and computational studies, led us to gain insight into the mechanistic aspects of these reactions that could help to a rational design of better catalytic systems.