Old strategies and New Tools: an Amazing Cocktail for an Organic Frontier Chemistry

MOCCI, RITA

2019-02-12

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Abstract

In the last three decades, the general sensitivity of public opinion toward environmental problems has certainly evolved. Indeed, a higher grade of awareness about the effect on the environment caused by industrial non-regulated production has been registered in the last century. At the same way, several chemicals were not known to be toxic and dangerous for human health. Despite the remarkable achievement carried out in this field, the mandatory goal of designing more eco-friendly procedures is not trivial and is part of the ongoing actual research. Within the aim of developing efficient organic synthetic strategies, our research group focuses on the goal of solvent elimination and maximization of energy efficiency, by means of ball milling technology. It has already been demonstrated that such method can be helpful in order to perform a process in absence of solvents, avoiding the drawback to them related. Mechanochemistry can be usefully applied to extend the scope of existing methodologies to non-soluble reactants, and to explore alternative paths not observable in solution. More specifically this thesis describes the study of mechanochemical methodologies for the synthesis of compounds of remarkable relevance. A solvent-less procedure is described for Hydroxamic acid derivatives, important synthetic target seen their important biological activity. Furthermore, object of this work has been the setting up of a methodology for the synthesis of isocyanide. Due to its extraordinary reactivity, isocyanide moiety plays a crucial role in organic synthesis and more specifically in multicomponent reactions. As a part of this study, we explored further transformation on the mechanochemical obtained isocyanide, exploiting its reactivity in a modified Bargellini reaction for the synthesis of 3-Carboxamido-Isobutyric Acids. Catalytic methods play a crucial role in green synthesis. Their use allows to avoid stoichiometric reagents, can minimize energy waste lowering energy activation barrier, open route to reactivities otherwise not achievable. In the present work, a catalytic reaction has been investigated with the aim of combining the catalytic approach to the mechanochemical one, starting from a solution based method. The reaction of borrowing hydrogen is characterized by a high atom economy, but common procedures implies high operational temperatures. The present work describes the investigation of the synthesis of secondary amines in presence of Ru and Os catalysts at room temperature.