The aim of this Ph.D. work is to establish different approaches for the synthesis of oxindoles and aza-oxindoles. Oxindoles and aza-oxindoles are common and important structural motif in natural products and biologically active molecules. In this thesis, we report a robust, cheap, efficient, and high atom economic protocol for the synthesis of oxindoles and aza-oxindoles, which relied on the direct oxidative coupling of an aromatic Csp2−H and a Csp3−H center. The reaction was mediated by inexpensive CuCl2 and did not require the presence of specifically functionalized precursors. The key step of this transformation is an intramolecular radical cyclization reaction. In the course of these studies we have discovered yet another novel route for the base promoted synthesis of 3,3-disubsituted aza-oxindoles. Mechanistic study and DFT calculation suggest that the reaction proceeds via a Truce-Smiles rearrangement/nucleophilic substitution pathway.