Estudios Sintéticos y Mecanísticos de Reacciones Orgánicas Radicalarias Iniciadas Mediante Procesos Fotorredox
In the present document, a thorough study of synthetic and mechanistic aspects of radical perfluoroalkylation reactions of three families of organic compounds, i.e.: electron-rich (hetero)aromatic compounds, sulfides and olefins, is illustrated. The electrophilic perfluoroalkyl radical species are g...
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| Formato: | Tesis doctoral acceptedVersion |
| Lenguaje: | Español |
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Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica
2019
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| Acceso en línea: | http://repositoriouba.sisbi.uba.ar/gsdl/cgi-bin/library.cgi?a=d&c=posgraafa&cl=CL1&d=HWA_6384 https://repositoriouba.sisbi.uba.ar/gsdl/collect/posgraafa/index/assoc/HWA_6384.dir/6384.PDF |
| Aporte de: |
| Sumario: | In the present document, a thorough study of synthetic and mechanistic aspects of radical perfluoroalkylation reactions of three families of organic compounds, i.e.: electron-rich (hetero)aromatic compounds, sulfides and olefins, is illustrated. The electrophilic perfluoroalkyl radical species are generated through visible-light photoredox catalysis. The thesis will highlight the following aspects: (i) a synthetic methodology using Rose Bengal as organic photocatalyst for homolytic aromatic substitution reactions of aniline derivatives with perfluoroalkyl moieties which will include the perfluoroalkylation of compounds with pharmacological activity; (ii) being the role of additives in the optimization of photocatalytic reactions a subject of great relevance, a chapter will be devoted to studying the use of additives and sacrificial donors in the radical substitution reactions of anilines, pyridines and pyrimidines with perfluoroalkyl groups. Emphasis will be made on the development of photoactive radical initiators based on Electron Donor Acceptor complexes between nitrogen-organic bases and perfluoroalkyl iodides; (iii) the perfluoroalkylation reactions of organic sulfides by means of photoinitiated radical nucleophilic substitutions (SRN) will be discussed in Chapter IV. Examples of sulfides of biological and biotechnological relevance will be studied. (iv) A novel photocatalytic methodology will be presented for the perfluoroalkylation reactions of organic sulfides and (hetero)aromatic compounds utilizing the low power irradiation source from red LEDs. (v) As final Chapter, a comprehensive, comparative and integrative study of three photocatalytic systems absorbing at three different wavelengths (violet, green, and red regions of the electromagnetic spectrum) will be investigated for three families of organic substrates (arenes, olefins, and sulfides) in terms of quantum yields, chain lengths, and quenching fractions, in order to irrevocably establish the reaction pathways and mechanistic details underlying in the substitutions with perfluoroalkyl groups. This latter study, will cast light on the presence of open and/or closed photocatalytic cycles |
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