Transition metal catalyzed cyclizations and C-H couplings of heterocyclic scaffolds

This thesis work is consecrated to the study of transition metal-catalyzed C-H activation processes for the synthesis or the functionalization of heterocycles. First, a new example of divergent catalysis was developed, which involves the employment of palladium tetrakis complex for the hydroamination or Pt(II) salts for the C-H hydroarylation reaction of O-propargyloxy anilines. The resulting benzopyranes are lately employed through a three steps efficient synthesis for the preparation of pyrano[3,2-h]quinolins. A new efficient version of Ru(0)-catalyzed carbonylative Murai reaction for the C3-H acylation was investigated using bidentate or aromatic imines as directing group. The coupling with vinylsilanes or styrenes was extended to a series of pentatomic heterocycles with moderate or excellent yields and the reaxtion mechanism was clarified by DFT calculation. Lastly, a totally new oxidant-free version of Ru(0)-catalyzed Fujiwara-Moritani reaction was studied. The trimeric complex of Ru3(CO)12 was employed for the C3-alkenylation with acrylates or electronpoor olefins with moderate or excellent yields. The reaction mechanism seems to proceed, after the activation step and the olefin insertion, through a -elimination step followed by a reductive elimination of the metal species formed.