Access To N-Based Heterocycles Via Sustainable Approaches

The main driving force in the development of new procedures for the construction of nitrogen heterocycles is represented by their ubiquity. Indeed, this class of organic scaffolds is frequently encountered in natural and synthetic bioactive products, agrochemicals and materials. The formation of new C–N bonds is one of the most fertile fields of research in organic chemistry, and a plethora of approaches are pursued for this goal. However, traditional strategies often suffer from having a negative impact on the environment. The use of hazardous solvents, noble metals, high temperatures and waste-producing methods is very common, although none of those features is aligned with the principles of green chemistry. Considering the ever-rising concerns regarding the conditions of the environment we live in, the urge to develop eco-friendly techniques is undeniable. During this PhD course, the goal of developing sustainable methods for the synthesis of various N-heterocycles has been achieved. This thesis reports the results of four methodology works (three of which have been published, and one will be submitted soon), in which the accessed scaffolds are: • azacarbolines, via an intramolecular oxidative cyclization of α-indolyl-hydrazones promoted by PhIO2, an iodine (V) reagent; • pyrrolo[2,3-b]indoles, obtained by the intramolecular oxidative amination of α-indolyl-hydrazones catalyzed by a combination of Cu (II) and Fe(III) salts in water as the sole solvent; • 1-aminoindoles, prepared by treating α-anilinyl-hydrazones with PIFA, an iodine (III) reagent; • and 1-aminopyrroles, via a formal FeIII-catalyzed [3 + 2] cyclodimerization of 1,2-diaza-1,3-dienes.