Visible-light-mediated arylation of ortho-hydroxyarylenaminones: direct access to isoflavones

Abstract

The first visible-light-promoted direct synthesis of isoflavones following the arylation of ortho-hydroxyarylenaminones by aryl onium salts was developed.

Aryldiazonium Salts in Photoredox Catalysis – Recent Trends

“…The other method involves diaryliodonium triflate as an arylating agent and Ru(bpy) 3 Cl 2 as photocatalyst under blue light irradiation (Scheme 12). [30] Diazonium salts containing different functional groups were well tolerated and the same was the case with substituted ortho ‐hydroxy enaminenone. The aryl radicals generated via oxidative quenching of excited photocatalyst react with ortho ‐hydroxyaryl enaminenone to give α‐amino radical intermediate ( A ).…”

Recent Progress in Radical Arylation Reaction with Diaryliodonium Salts under Photocatalysis

“…Control experiments implied that the phenyl In 2020, the consecutive domino arylation of orthohydroxyaryl enaminones with in situ photogenerated aryl radicals from diaryliodonium salts for the synthesis of isoflavones was described by Mkrtchyan group (Scheme 9). [26] The desired products were obtained with good to excellent yields. Additionally, diazonium salts was also suitable for this reaction instead of diaryliodonium salts.…”

Eosin: a versatile organic dye whose synthetic uses keep expanding

“…In 2017 and 2020, the groups of Jin/Cheng 38 and Mkrtchyan/Iaroshenko, 39 respectively, published new methods that used aryldiazonium tetrafluoroborates 95 as a source of aryl radicals (Scheme 23). In both cases, it is proposed that excited state eosin donates an electron (*EY → EY •+ ) to the aryldiazonium tetrafluoroborate 95 which subsequently fragments to generate the aryl radical ( • Ar).…”

“…Finally, elimination of Me 2 NH yields the product 98. 39 In both cases, the products were targeted due to their ubiquity; firstly, it is well-known that indoles are extremely common in bioactive natural products and synthetic compounds. Chromones are also privileged heterocycles abundant not only in nature, but in synthetic compounds with a range of applications (from use in the life sciences to uses in the food industry).…”