Recent Advances in Photocatalytic Functionalization of Quinoxalin‐2‐ones

Abstract

Visible-light-mediated chemical reactions have become highly popular in the last ten years. This review covers the recent developments in visible-light photofunctionalization of quinoxalin-2-one derivatives. Reaction types have been categorized depending on the kind of bond formed: CC , CO , [a

Direct Photoexcitation of Benzothiazolines: Acyl Radical Generation and Application to Access Heterocycles

“…These photophysical study results encouraged us to further evaluate the photochemical application of the excited C(2)-benzoyl-substituted benzothiazoline (1a*). Considering the importance of C(3)-substituted quinoxalin-2-ones [44,45], we selected photo-promoted structural modification of quinoxalin-2-one as a model reaction. It was found that the mixture of 1a with quinoxalin-2-one 2a under the sole irradiation of blue LED in CHCl3 after These photophysical study results encouraged us to further evaluate the photochemical application of the excited C(2)-benzoyl-substituted benzothiazoline (1a*).…”

“…It was found that the mixture of 1a with quinoxalin-2-one 2a under the sole irradiation of blue LED in CHCl3 after These photophysical study results encouraged us to further evaluate the photochemical application of the excited C(2)-benzoyl-substituted benzothiazoline (1a*). Considering the importance of C(3)-substituted quinoxalin-2-ones [44,45], we selected photo-promoted structural modification of quinoxalin-2-one as a model reaction. It was found that the mixture of 1a with quinoxalin-2-one 2a under the sole irradiation of blue LED in CHCl 3 after 4 h led to the desired C3-acylated product 3aa in 38% isolated yield (Figure 1d).…”

Visible Light-Promoted Radical Relay Cyclization/C–C Bond Formation of N-Allylbromodifluoroacetamides with Quinoxalin-2(1H)-ones

“…Quinoxalin-2­(1 H )-ones are widely present in numerous bioactive natural products and pharmaceuticals because of their significant biological activities and outstanding chemical properties (Scheme a). , Direct functionalization of quinoxalin-2­(1 H )-ones, especially at the C3 position, is a convenient method to expand their structural diversity. In recent years, impressive advances have been made to access 3-substituted quinoxalin-2­(1 H )-ones through transition-metal-catalyzed or visible light-induced functionalization, including arylation, acylation, phosphonation, amination, or trifluoromethylation (Scheme a) . Despite that a range of functionalized quinoxalin-2­(1 H )-ones have been prepared, the structural complexity and chemical space for this class of hetereocycles are still highly expected to be expanded by exploiting new synthetic pathways.…”

O-Perhalopyridin-4-yl Hydroxylamines: Amidyl-Radical Generation Scaffolds in Photoinduced Direct Amination of Heterocycles

“…Gratifyingly, the target product tert -butyl (4-methyl-3- oxo -3,4-dihydroquinoxalin-2-yl)­carbamate ( 3a ) was obtained in 66% yield under irradiation of 30 W blue LEDs without adding any photocatalyst. Notably, such nitrogen-containing heterocycles are widely encountered in natural products and pharmaceuticals with a range of biological activities . To shed more light on the nature of the present reaction, further control experiments were launched.…”