Two main topics were addressed in this manuscript: (1) New methods for indoles and [3,4]-fused oxindoles syntheses; (2) Copper-catalyzed/mediated difunctionalization of alkenes with alkylnitriles. Given the omnipresent character of the indole and oxindole ring systems, their synthesis and functionalization are a research area of main interest. Two different strategies have been developed for the indole motif synthesis. The first method implies a Cucatalyzed heteroannulation of ortho-aminophenylboronic ester and β-ketoester under mild, base free conditions. The second strategy consists in the synthesis of N-arylindoles via a benzannulation reaction with α-N-aryl aminoketone and 2-(trimethylsilyl)phenyl trifluoromethanesulfonate as benzyne precursor. The benzannulation reaction was applied to the synthesis of 5,6-dihydroindolo[1,2-a]quinolone by using cyclic α-N-aryl aminoketone, obtained in one step from commercial compounds via the three-component Povarov reaction. Afterwards, we developed a novel Pd(0)-catalyzed domino reaction, involving carbopalladation/1,4-Pd shift via double C-H bond activation/C-C bond formation for the synthesis of [3,4]-fused oxindoles. In the second part of the manuscript, we addressed the copper-catalyzed difunctionalization of alkenes. The difunctionalization of olefin represents a domain of main interest in organic synthesis due to the availability of the starting material and the possibility to reach high complexity and diversity of products in one single step. We developed a methodology that allows the introduction of a "C(R')(R)CN" group by coppercatalyzed difunctionalization of alkene, using the alkyl nitriles as reaction partner. By applying this methodology, different functionalized classes of compounds were synthesized: phthalides, γ-lactone and isochromanones, epoxides and ketones.