Aplicaciones derivadas de la fotoquímica de O-aciloximas stars

Resumo

This Thesis deals with the applications of acyloximes. The irradiation of these compounds generates iminyl radicals which can lead to nitrogen containing heterocycles by ring closure. Aims are described (Chapter 3) after an introduction (Chapter 1) and a background (Chapter 2). In this chapter, the photochemical reactivity of acyloximes and the reaction mechanism studies throughout experimental and computational techniques are summarized. In Chapter 4, it is explained how the acyloximes are irradiated in the presence of alkynyl Fischer carbene complexes, which constitutes the first example of a photochemically driven reaction of this kind. When the radical participates in a 1,4- addition to alkynylcarbene complexes 5-aza-1-metalla-1,3,5-hexatriene where obtained, while the 1,2 addition led to azepines. In Chapter 5, the synthesis of more complex acyloximes to give new nitrogen containing heterocyclic compounds by the photochemically generated iminyl radicals is described. This strategy also has been used to obtain natural products, such as trisphaeridine and the precursor of some alkaloids, such as vasconine, assoanine, oxoassoanine and pratrosine. In Chapter 6, the first trisphaeridine derivatives substituted on both the 7- and 10- positions of phenanthridine skeleton are described. Moreover, the effect of the substituents has been elucidated by studying the electrochemical and photophysical properties of the new compounds. These studies have been supported by DFT and TDDFT calculations. Finally, it was found that these new trisphaeridine derivatives are fluorescent. Therefore, they are capable of detecting protons and metal ions depending on the substituent because of the fact that changes in their fluorescence spectra are observed. In conclusion, we have obtained new compounds that can be used as fluorescence sensors.