Synthetic and mechanistic investigation of new radical processes: reaction of organic azides with group-XIII Lewis acids

Dichloroindium hydride revealed to be a valid alternative to tributyltin hydride for radical reduction of organic (alkyl, aryl, acyl, solfonyl) azides. The new approach entails mild reaction conditions and provides high yields of the corresponding amines and amides, also showing high degrees of selectivity. The system dichloroindium hydride / azides can be utilised in fivemembered ring closures of g-azidonitriles, as a new source of aminyl radicals for the attractive synthesis of interesting amidine compounds in the absence of both toxic reagents and tedious purification procedures. Allylindium dichloride seems a good substitute for dichloroindium hydride for generation of indium centred radicals under photolytic conditions, since it allows allylation of electrophilic azides (e.g. phenylsulfonyl azide) and halogen or ester δ-substituted azides, the latter through a 1,5-H transfer rearrangement mechanism. Evidences of the radical nature of the reactions mechanism were provided by ESR spectroscopy, furthermore the same technique, allowed to discover that the reaction of azides with indium trichloride and other group XIII Lewis acids, in particular gallium trichloride, gives rise to strongly coloured, persistent paramagnetic species, whose structure is consistent with the radical cation of the head-to-tail dimer of the aniline corresponding to the starting azide.

Una danza di parti interagenti. Gregory Bateson pensiero ecologico e educazione

The thesis focuses on the ecological thought of Gregory Bateson and the contributions that such epistemology can offer nowadays to the educational scene, connecting in particular to the problematicistic perspective of Giovanni Maria Bertin with the aim of rethinking and updating it. The writing explicates the meaning of education to an ecological knowledge, that privileges connections, creativity and solidarity with the living world. The work analyzes, moreover, the cultural and epistemological value of relations focusing on ethic commitment as an instrument of promotion of the right to difference. A final part of the work is dedicated to some ecological aspects such as environmental safeguard and development, fundamental topics especially for the educational context.