Beyond any doubt, the selective functionalization of inert C–H bonds of petroleum-based derivatives is one of the holy grails in synthetic chemistry. In the past decades, noble transition metals have played an essential role in this kind of transformations. However, in the past few years, more cost-effective first-row transition metals, such as cobalt, have emerged as an attractive alternative to precious metals.
More recently, the employment Cp*CoIII complexes, has represented a tremendous advance in cobalt catalysis. Despite this significant progress, these cobalt systems are still at their infancy when compared to well-known Rh- and Pd-based catalysts. This is because fundamental questions, specially concerning the underlying reaction mechanisms, remain unsolved.
The main goal of this PhD thesis is to try to shine some light into the unexplored mechanistic landscape of the Cp*Co-catalyzed C–H functionalization reactions. In this context, the first objective has been to develop reliable synthetic routes for the synthesis, isolation and characterization of direct analogues of long-sought cyclometallated Cp*CoIII intermediates. We applied this knowledge to start understanding one of the fundamental steps in these transformations: the migratory insertion. Finally, we tackled the challenges associated to the reversible nature of the C–H metalation step in Cp*CoIII systems. In addition, it was revealed the beneficial effect of fluorinated alcohols not only in this cyclometalation reaction but also in different benchmark catalytic transformations.