New Applications of Flavin Photocatalysis

Svobodová, Eva; Cibulka, Radek

doi:10.1002/9783527830138.ch11

Cited by 9 publications

(3 citation statements)

References 81 publications

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“…[13] Blue-light activation of flavins generates a flavosemiquinone radical state, which is central to the chemical reactivity of enzymes such as DNA photolyases and cryptochromes, [14] and in photocatalysis manifolds, where it can be channeled into productive chemical transformations. [15][16][17][18] Flavosemiquinone radicals are located on the N,O site of flavin (C4a position), yet studies on simpler models have established the central role of the aromatic and 1,4-diazine rings in the stabilization of electronic density. [19] Flavosemiquinones react with triplet oxygen at the N,O site to generate a highly reactive hydroperoxo species, which performs a wide range of reactions, such as oxidation and halogenation.…”

Section: Introductionmentioning

confidence: 99%

Site‐Selective Radical Aromatic C−H Functionalization of Alloxazine and Flavin through Ground‐State Single Electron Transfer

Das,

Charpentier,

Hessin

et al. 2024

Angewandte Chemie

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Flavins and their alloxazine isomers are key chemical scaffolds for bioinspired electron transfer strategies. Their properties can be fine‐tuned by functional groups, which must be introduced at an early stage of the synthesis as their aromatic ring is inert towards post‐functionalization. We show that the introduction of a remote metal‐binding redox site on alloxazine and flavin activates their aromatic ring towards direct C–H functionalization. Mechanistic studies are consistent with a synthetic sequence involving ground state single electron transfer (SET) with an electrophilic source followed by radical‐radical coupling. This unprecedented reactivity opens new opportunities in molecular editing of flavins by direct aromatic post‐functionalization and the utility of the method is demonstrated with the site‐selective C6 functionalization of alloxazine and flavin with a CF3 group, Br or Cl, that can be further elaborated into OH and aryl for chemical diversification.

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Section: Introductionmentioning

confidence: 99%

Site‐Selective Radical Aromatic C−H Functionalization of Alloxazine and Flavin through Ground‐State Single Electron Transfer

Das,

Charpentier,

Hessin

et al. 2024

Angewandte Chemie

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“…The flavin catalyst Fl is excited by visible light irradiation to the triplet state 3 Fl* via the singlet state 1 Fl* , resulting in a positive redox potential shift 8 f and catalysis of various reactions. 10 a ,21 Electron transfer and the subsequent proton transfer to 3 Fl* converts benzylamine ( 1 ) into benzylamine radical ( 9˙ ). 8 e The electron transfer from 1 is supported by the Stern–Volmer plot for 1a that showed a linear decrease in the emission intensity of 4 as the amount of 1a increases (Fig.…”

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confidence: 99%

Aerobic oxidative synthesis of benzimidazoles by flavin photocatalysis

Shiogai,

Oka,

Miyake

et al. 2024

Org. Biomol. Chem.

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“…Upon photo-irradiation, the flavin catalyst Fl is known to generate excited 3 Fl* via the intermediary 1 Fl* , which possesses a positively shifted redox potential, 15 b resulting in diverse catalysis. 12 a ,19 By generating ArCH 2 ˙ through electron transfer to 3 Fl* , the benzylic C–H bonds of 1 are oxidatively activated to form the corresponding aldehyde 9 , 13 c ,15 which then undergoes nucleophilic attack by 2 , forming 10 through dehydrative condensation. As suggested by the control experiments in Scheme 4Db, the flavin catalyst enhanced the dehydrogenative aromatisation of 10 to 3 .…”

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confidence: 99%