Visible light flavin photo-oxidation of methylbenzenes, styrenes and phenylacetic acids

Abstract

We report the photocatalytic oxidation of benzylic carbon atoms under mild conditions using riboflavin tetraacetate as photocatalyst and blue-emitting LEDs (440 nm) as light source. Oxygen is the terminal oxidant and hydrogen peroxide appears as the only byproduct in most cases. The process oxidizes toluene derivatives, stilbenes, styrenes and phenylacetic acids to their corresponding benzaldehydes. A benzyl methyl ether and acylated benzyl amines are oxidized directly to the corresponding methyl ester or benzylimides. The mechanism of the reactions has been investigated and the results indicate that oxygen addition to benzyl radicals is a key step of the oxidation process in the case of phenylacetic acids.

Blue Light-induced Dimerization of Monomeric Aureochrome-1 Enhances Its Affinity for the Target Sequence

“…probably because of the photocatalytic activity of FMN (25,26). When excluding the data of the samples containing aggregated protein with H 2 O 2 ( Fig.…”

Solvent-free, visible-light photocatalytic alcohol oxidations applying an organic photocatalyst

“…RFTA and flavin derivatives in general are well-known blue-light absorbing photocatalysts, which can oxidize a variety of substrates under aerobic conditions with oxygen as terminal oxidant. Flavins were studied extensively for the oxidation of alcohols, amines, methylbenzenes, styrenes, and phenylacetic acids [9–12]. Some derivatives were also immobilized on silica gel and applied in the oxidation of benzyl alcohols [13].…”

The concept of photochemical enzyme models – State of the art

“…4) have already been identified [43,95]. A key-process required for triggering an efficient visible-light mediated activation of molecular oxygen with high turnover numbers is the photosensitization of metal-centered triplet excited states of redox-active main group element compounds (Fig.…”