Metal-free photoredox-catalyzed direct α-oxygenation of N,N-dibenzylanilines to imides under visible light

Abstract

A visible-light-mediated direct α-oxygenation of N,N-dibenzylanilines to imides in the presence of [Acr+-Mes]BF4 as a metal-free photocatalyst and O2 as a green oxidant.

Green and sustainable visible light-mediated formation of amide bonds: an emerging niche in organic chemistry

“…In this context, Anandhan and his colleague reported an efficient synthesis of imides 64 via direct α-oxygenation of N , N -disubstituted anilines 60 using molecular oxygenation as a green oxidant under visible light illumination (Scheme 27). 89 A variety of N , N -disubstituted anilines were employed under the reaction conditions, and the corresponding imides were obtained in good yields. Unfortunately, aliphatic amines and heteroaryl amines were unable to produce the required products.…”

A facile synthesis of phthalimides from o-phthalaldehyde and amines via tandem cyclocondensation and α-C–H oxidation by an electrochemical oxygen reduction reaction

“…Thereby, the direct use of O 2 as an oxidant in the α-oxygenation of amines has been well documented through conventional 20 and photochemical methods. [21][22][23][24] The electrochemical reaction with molecular oxygen has provided new avenues in synthetic transformations because molecular oxygen undergoes the oxygen reduction reaction (ORR) at the cathode to give reactive intermediates such as the superoxide radical anion O 2…”

“…Thereby, the direct use of O 2 as an oxidant in the α-oxygenation of amines has been well documented through conventional 20 and photochemical methods. 21–24…”

Visible-Light Promoted Regioselective Oxygenation of Quinoxalin-2(1H)-ones Using O2 as an Oxidant

“…Oxygenation reaction is one of the essential and powerful tools to synthesize oxygen-containing molecular scaffolds, which are prevalent in bioactive and natural products. − Oxygen-containing organic compounds have a wide array of industrial and pharmaceutical applications such as cosmetics, anticoagulants, antibiotics, nutrients, and so forth. , Oxygenation utilizing molecular oxygen as an eco-friendly and green oxidant under visible-light photocatalysis is the most convenient and sustainable strategy among variously reported protocols. ,,− For instance, in 2018, Das and co-workers demonstrated α-oxygenation of tertiary amines under visible light irradiation using Rose Bengal as a photocatalyst and O 2 as the oxidant (Figure b) . In 2020, the same group reported dearomatization of indoles in the presence of oxygen using Rose Bengal as a visible-light photocatalyst (Figure c) …”