Synthesis and Study of Functionalized Porphyrins as Organophotoredox Catalysts
[eng] Visible-light photocatalysis is currently one of the hottest research areas in organic chemistry, due to the possibility that offers to form C-C and C-Het bonds in a green, non-toxic and efficient way. Although visible-light photocatalysis has been the object of unabated interest in the last f...
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| Format: | doctoral thesis |
| Status: | Published version |
| Publication Date: | 2022 |
| Country: | España |
| Institution: | Universidad de Barcelona |
| Repository: | Dipòsit Digital de la UB |
| OAI Identifier: | oai:diposit.ub.edu:2445/192125 |
| Online Access: | https://hdl.handle.net/2445/192125 http://hdl.handle.net/10803/687402 |
| Access Level: | Open access |
| Keyword: | Química orgànica Catàlisi asimètrica Porfirines Organic chemistry Enantioselective catalysis Porphyrins |
| Summary: | [eng] Visible-light photocatalysis is currently one of the hottest research areas in organic chemistry, due to the possibility that offers to form C-C and C-Het bonds in a green, non-toxic and efficient way. Although visible-light photocatalysis has been the object of unabated interest in the last few years, the development of catalytic enantioselective light-driven processes is still an extremely challenging task. That is why a large number of research groups have dedicated their efforts to trying to make photocatalysis coexist with asymmetric catalysis. In this sense, asymmetric photocatalytic transformations have been successfully achieved by using two different methodologies; the so-called dual catalysis, where photocatalysts are combined with chiral co- catalysts that work in a tandem fashion for a single chemical reaction, and the so-called, bifunctional catalysis, where a single catalyst perform both photo- and organo-catalysis, being the latter the less explored methodology due to the complexity of finding and synthesizing a suitable bifunctional catalyst. In the last years, porphyrins, such as meso-tetraphenylporphyrin (TPP), have showed up as a suitable organic photocatalyst for the development of new methodologies for the construction of new C-C and C-Het bonds, thus avoiding the use of metal-based photocatalysts. In this field, some recent works show their capacity for acting as photoredox catalysts in the racemic organophotocatalytic alpha-alkylation reaction of aldehydes with diazoacetates, being unexplored their asymmetric version. In the light of our interest of new catalytic applications of porphyrins, we were particularly attracted by these reports. This present work is focused on the study of the asymmetric Diels-Alder cycloaddition in both thermal and photochemical conditions and development of a practical enantioselective version of the organophotocatalytic alpha-alkylation of aldehydes with diazoacetates. Moreover, we present different porphyrin-based bifunctional photoaminocatalysts based on the combination of both an organocatalyst (chiral secondary amines) and a photocatalyst (porphyrin). |
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