Visible‐Light‐Induced Trifluoromethylation of Quinoxalin‐2(1H)‐Ones under Photocatalyst‐Free Conditions

Abstract

CÀ H trifluoromethylation of quinoxalin-2(1H)-ones with commercially available sodium trifluoromethanesulfinate (CF 3 SO 2 Na) under visible light irradiation without any external photocatalyst has been developed, providing a variety of 3-trifluoromethylquinoxalin-2(1H)-ones in moderate to excellent yield. Mechanistic studies have shown that 1 O 2 coexists with O 2 * À through the energy transfer and single-electron transfer processes during the photoredox reaction.

Metal‐Free Cyclocarboamination of ortho‐Formyl Phenylacetylenes with Secondary Amines: Access to 1,3‐Diamino‐1H‐Indenes and 3‐Amino‐1‐Indanones

“…Ortho ‐Formyl phenylacetylenes are versatile building blocks for many organic transformations through transition metal catalysis and organocatalysis . The carbon‐carbon triple bonds of ortho ‐formyl phenylacetylenes are generally activated by transition metals leading to highly reactive ylide intermediates, which are amendable to subsequent nucleophilic addition, [3+2]‐annulation, and [4+2]‐cycloaddition, to afford structurally diverse heterocyclic compounds ,. For example, we have reported a chemoselectively gold(III)‐catalyzed cyclization of ortho ‐formyl phenylacetylenes with trialkyl orthoformate .…”

“…For example, we have reported a chemoselectively gold(III)‐catalyzed cyclization of ortho ‐formyl phenylacetylenes with trialkyl orthoformate . Notably, ortho ‐formyl phenylacetylenes readily react with primary amines to give imines in which the nucleophilic nitrogen atom intramolecularly reacts with ortho ‐alkynyl (hydroamination) to yield diverse amines . Nevertheless, studies on reactions of ortho ‐formyl phenylacetylenes with secondary amines remain sparse ,,.…”

Recent Advances in Photocatalytic Functionalization of Quinoxalin‐2‐ones

“…The first example was the methodology reported by Jin et al, in which several differently substituted quinoxalin-2-ones were trifluoromethylated using CF 3 SO 2 Na under the irradiation of Blue LEDs, without the use of a photocatalyst. [49] The corresponding 3-trifluoromethyl-quinoxalin-2(1H)-one derivatives bearing a variety of substitution patterns were obtained in moderate to good yields (Scheme 28). Additionally, they performed enough experiences to ensure that both starting quinoxalin-2-one and 3-trifluoromethylquinoxalin-2-one might act as photosensitisers to generate singlet oxygen upon the irradiation of Blue LEDs through an Energy Transfer (ET) process.…”

“…These precursors have been employed by four research teams to generate trifluoromethyl or difluoromethyl radicals in order to fluoroalkylate quinoxalin‐2‐ones using visible‐light photocatalysis. The first example was the methodology reported by Jin et al, in which several differently substituted quinoxalin‐2‐ones were trifluoromethylated using CF 3 SO 2 Na under the irradiation of Blue LEDs, without the use of a photocatalyst . The corresponding 3‐trifluoromethyl‐quinoxalin‐2(1 H )‐one derivatives bearing a variety of substitution patterns were obtained in moderate to good yields (Scheme ).…”

Application of Photochemical/Electrochemical Synthesis in C—H Functionalization of Quinoxalin-2(1H)-one

“…该反应在 N 2 氛围下, 以 Ir(ppy 2019 年, 胡雨来等 [17] 在白色 LEDs 的照射下, 以喹 [18] 亦以 Ru(bpy 3 )Cl 2 [20] 12). 接着, 金灿等 [22] 与三氟烷基基团相比, 二氟烷基基团作为亲脂性氢 键供体, 对生物活性化合物具有重要作用, 在新型支架 的药物开发中具有潜在的价值, 引起了学者研究的兴 趣. 2019 年, 金灿等 [23] 15 Visible-light photoredox and organoamine catalysis for the C-3 difluoroalkylation of quinoxalin-2(1H)-ones 2020 年, 宣俊等 [24] 在蓝色 LEDs 光的照射下, 以 4-…”