Rose Bengal catalysed photo-induced selenylation of indoles, imidazoles and arenes: a metal free approach

Abstract

In this report, the highly efficient Rose Bengal-catalysed C(sp)-H selenylation of indoles, imidazoles and arenes was achieved using a half molar equiv. of diorganoyl diselenides. This metal-free, photo-induced protocol resulted in selenylated products in good to excellent yields. The reaction features are high yields, an atom-economic, gram-scalable and metal-free approach, and applicability to different biologically relevant (hetero)arenes.

Photoinduced, Direct C(sp2)−H Bond Azo Coupling of Imidazoheteroarenes and Imidazoanilines with Aryl Diazonium Salts Catalyzed by Eosin Y

“…Based on the control experiments reported in Scheme , the fluorescence experiments reported in the Supporting Information (p. S21 and S22), and Table (entry 18), as well as previous reports in the literature, two possible mechanisms, by means of ionic and radical pathways, could be simultaneously operating in this transformation, as proposed in Scheme .…”

“…In recent years, there has been a surge of interest in the development of new organic transformations through photoredox catalysis by the synthetic community, resulting in several interesting publications . In this regard, organic dyes such as eosin Y‐Na 2 , fluorescein, and rose bengal have emerged as versatile photocatalysts in the cross‐coupling reaction for C−C and C−X bond formation …”

An environmentally benign and efficient synthesis of 4‐Selanylpyrazoles catalyzed by haloid salts in water

“…of 1a with 1.0 equiv. for H 2 O 2 proved to be the best choices (entries 5, [16][17][18][20][21][22]. of oxidant H 2 O 2 and 15 mol% of NaCl in H 2 O for 6 hr at room temperature, the desired product, 3,5-dimethyl-1-phenyl-4--(phenylselanyl)-1H-pyrazole 3a was obtained in a good yield of 86% (Table 1, entry 1).…”

NIS/TBHP Induced Regioselective Selenation of (Hetero)Arenes via Direct C−H Functionalization

“…So far, only several protocols have been established on the basis of this strategy, which are promoted by bases, iodide reagents oxidants or visible‐light; some of methods were completed under metal‐free conditions using only a half molar equiv. of diaryl diselenides (Scheme d) –. Considering atom economy and environment protection, establishment of novel methods for the selenation of (hetero)arenes via direct C−H functionalization using 0.5 equiv.…”