PhDThe development of new procedures for the production of biologically and industrially relevant compounds still remains a big challenge in chemistry. The biaryl motif is ubiquitous among a wide range of compounds of industrial importance. For example, the biaryl skeleton is found in molecular switches and motors, agrochemicals or medicines such as antifungal, anticancer, antibiotics, anti-inflammatory treatments. These properties make the biaryl functionality a highly desirable synthetic target, for both commercial and research purposes. In this context, C–H arylation has been acknowledged as a useful alternative to traditional cross-couplings, replacing the organometallic coupling partner by a non-prefunctionalised substrate in the reaction with a haloarene. Approaches for the development of Ru-catalysed C–H arylation methodologies are presented herein. The introduction provides a general overview about different strategies employed in metalcatalysed direct C–H arylation methods. The rational behind selectivity and reactivity are also thoroughly discussed. The second chapter describes studies on the C–H activation of perfluorinated arenes by Ru(II)-species. The synthesis of unprecedented aryl rutyhenium complexes and mechanistic considerations on the metalation of the arene are presented. In the last part of the second chapter the development of a bis-cationic rutehium(II) complex able to catalyse direct C–H arylation of electron-poor arenes with bromoarenes in the absence of any directing group is described. A complete mechanistic analysis, along with the scope of the methodology, is therefore given
