New methodologies for the stereoselective synthesis and modification of nitrogen containing molecules

The chemistry of nitrogen-containing compounds is highly significant due to their numerous applications in various aspects of life. These compounds are fundamental to essential biomolecules that enable biological functions, such as amino acids (and consequently all proteins) and nucleic acids (DNA and RNA). Many biologically active natural and synthetic products contain nitrogen, with alkaloids and heterocycles such as piperidine, pyridine, piperazine, β-lactam, and pyrrolidine being some of the most prominent examples. Additionally, nitrogen-containing compounds serve as ligands and catalysts, further demonstrating their broad utility. For this reason, this PhD thesis focuses on the synthesis and functionalization of nitrogen-containing compounds, while also addressing sustainability issues whenever possible. The thesis is structured into distinct chapters, each dedicated to a specific project with a defined objective. Chapters 3 and 4 focus on the diastereoselective synthesis of substituted pyrrolidine scaffolds via the addition of organometallic species to chiral sulfinyl imines. Specifically, Chapter 3 describes the development of a new stereoselective synthesis of α-disubstituted β-amino acids. Chapter 4 details the design of a stereoselective synthesis for a key intermediate intended for the preparation of new Hayashi-type catalysts, in which the silyl ether moiety is replaced with a more stable alkyl ether moiety. Chapter 5 presents a new methodology based on EDA photochemistry for the enantioselective preparation of γ-amino aldehydes. Continuing the focus on photochemistry, Chapter 6 explores the possibility of improving the sustainability of a known photocatalytic α-arylation of amines by conducting the reaction in green media and recycling the metal-based photocatalyst. Finally, Chapter 7 investigates the hydrofunctionalization of allenamides to generate γ-heterosubstituted enamides, with sustainability and broad applicability as central objectives.