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Structural modifications of pyrazine-2,3-dicarbonitrile: Towards a series of efficient photoredox catalysts

Authors: Hloušková Zuzana | Bureš Filip

Year: 2018

Type of publication: ostatní - přednáška nebo poster

Page from-to: nestránkováno

Titles:

Language	Name	Abstract	Keywords
eng	Structural modifications of pyrazine-2,3-dicarbonitrile: Towards a series of efficient photoredox catalysts	The original idea to use visible light as a stimulant agent for promoting organic transformation is more than hundred years old. Nowadays, transformation of solar to chemical energy represent very burgeoning area of organic and material chemistry. This process can be in a chemical laboratory accomplished by using a photoredox catalyst. In general, an (organic) compound that absorbs light in a visible region of the spectrum being capable to undergo photoinduced electron transfer with subsequent easy regeneration are currently sought. Several years ago, an efficient photocatalyst based on 4,5-disubstituted pyrazine-2,3-dicarbonitrile has been developed in our group. This organic push-pull molecule proved to be highly efficient catalyst in various visible light promoted reactions such as cross-dehydrogenative coupling, oxidation, oxidative hydroxylation, and reductive dehalogenation. These astonishing results lead to further investigation of catalytic activity and substrate scope of pyrazine derivative in further photoredox reactions such as unprecedented chemodivergent radical cascade reactions between N tetrahydroisoquinolines and N itaconimides. In 2016, pH-controlled photooxygenation of indoles and enantioselective oxidative C(sp3)-H olefinations have also been developed. Further structural modifications and property tuning of this successful photocatalyst have recently been carried out aiming on elucidation of thorough structure-property relationship.4 The structural tuning includes variation of: i) the acceptor moiety such as pyrazine- vs. imidazole-dicarbonitrile,5 ii) the electron releasing moieties, iii) the X- and Y shaped arrangement, and iv) the length and composition of the pi-linker. Fundamental properties of the newly synthesized catalysts were investigated by X ray analysis, electrochemistry and electronic absorption/emission spectra. In this contribution, aforementioned systematic variations, synthesis of all catalysts, and their application in selecte	pyrazine-2,3-dicarbonitrile; push-pull molecules; photocatalysis