Chemoselective synthesis of diaryl disulfides via a visible light-mediated coupling of arenediazonium tetrafluoroborates and CS₂

• Jing Leng,
• Shi-Meng Wang and
• Hua-Li Qin

Beilstein J. Org. Chem. 2017, 13, 903–909, doi:10.3762/bjoc.13.91

• and to minimize the formation of the byproducts was conducted. As recently surveyed, photoredox catalysts are widely employed for the generation of radicals for diverse radical reactions [19]. Further, the application of aryl radicals generated from aryldiazonium salts under visible light irradiation

• radical I was initially generated under visible light irradiation [14][15]. Subsequently, the radical I attacked the sulfur atom of carbon disulfide to provide the intermediate II which can be converted to radical intermediate III through the cleavage of the carbon–sulfur bond accompanied with the release

Copper-catalyzed asymmetric sp³ C–H arylation of tetrahydroisoquinoline mediated by a visible light photoredox catalyst

• Pierre Querard,
• Inna Perepichka,
• Eli Zysman-Colman and
• Chao-Jun Li

Beilstein J. Org. Chem. 2016, 12, 2636–2643, doi:10.3762/bjoc.12.260

• , entries 7 and 8). A tentative reaction mechanism has been proposed in Scheme 3, in order to rationalize this arylation reaction. Upon visible light irradiation, [Ir(ppy)2(dtbbpy)]PF6 I was converted into an excited state II, Ir(III)* [11][33][34][35][36][37]. The THIQ undergoes a single electron transfer

Solvent-free, visible-light photocatalytic alcohol oxidations applying an organic photocatalyst

• Martin Obst and
• Burkhard König

Beilstein J. Org. Chem. 2016, 12, 2358–2363, doi:10.3762/bjoc.12.229

• substrates would be grinded under visible light irradiation. In contrast to mechanochemistry, the process would be driven by light energy and not by mechanical energy, but profit from the absence of toxic solvents, high concentrations of the substrate, and easy work-up. Furthermore, undesired effects of the

Synthesis of photoresponsive cholesterol-based azobenzene organogels: dependence on different spacer lengths

• Yuchun Ren,
• Bin Wang and
• Xiuqing Zhang

Beilstein J. Org. Chem. 2015, 11, 1089–1095, doi:10.3762/bjoc.11.122

• organogelators and soft matter. Changes in the absorption over time in the UV–vis spectra of dilute THF solution of M0: (a) upon UV-light irradiation (λ = 365 nm) and (b) upon visible-light irradiation (λ = 450 nm) of the solution obtained after irradiation of 365 nm. DSC thermogram of the compounds M0-n

• obtained on (a) heating and (b) cooling. Photographic images of the M6 sol-gel transition behavior after UV or visible light irradiation in different solution (a) ethanol, (b) isopropanol and (c) 1-butanol. SEM images of xerogels formed with M6 from solution: (a) ethanol, (b) isopropanol and (c) 1-butanol

Come-back of phenanthridine and phenanthridinium derivatives in the 21st century

• Lidija-Marija Tumir,
• Marijana Radić Stojković and
• Ivo Piantanida

Beilstein J. Org. Chem. 2014, 10, 2930–2954, doi:10.3762/bjoc.10.312

An integrated photocatalytic/enzymatic system for the reduction of CO₂ to methanol in bioglycerol–water

• Michele Aresta,
• Angela Dibenedetto,
• Tomasz Baran,
• Antonella Angelini,
• Przemysław Łabuz and
• Wojciech Macyk

Beilstein J. Org. Chem. 2014, 10, 2556–2565, doi:10.3762/bjoc.10.267

• , and the in situ photocatalytic reduction of NAD+ to NADH under visible-light irradiation, using semiconductors in water/bioglycerol mixtures. Bioglycerol is being produced in increasing volumes for bio-diesel production from oleaginous seeds. New applications for this product are being investigated [7

• active isomers upon visible-light irradiation in order to make the enzymatic reduction of CO2 to CH3OH viable. Results and Discussion In previous work [7] we demonstrated that encapsulated FateDH, FaldDH, and ADH enzymes are able to rapidly (<1 min) reduce CO2 in proton–donor solvents under pH-controlled

• . Therefore, we have synthesized a number of semiconducting materials showing photocatalytic activity under visible-light irradiation. The most active material was selected and fully characterized regarding its photoelectrical- and chemical-properties. Optimal conditions for use with visible light for the

Direct C–H trifluoromethylation of di- and trisubstituted alkenes by photoredox catalysis

• Ren Tomita,
• Yusuke Yasu,
• Takashi Koike and
• Munetaka Akita

Beilstein J. Org. Chem. 2014, 10, 1099–1106, doi:10.3762/bjoc.10.108

• –CF3 bonds is highly demanded. Results: The photoredox reaction of alkenes with 5-(trifluoromethyl)dibenzo[b,d]thiophenium tetrafluoroborate, Umemoto’s reagent, as a CF3 source in the presence of [Ru(bpy)3]2+ catalyst (bpy = 2,2’-bipyridine) under visible light irradiation without any additive afforded

• examination of photocatalytic trifluoromethylation of 1,1-diphenylethene 2a with 1 equivalent of Umemoto’s reagent 1a in the presence of 5 mol % fac-Ir(ppy)3, a photoredox catalyst, and 2 equivalents of K2HPO4, a base, in [D6]-DMSO under visible light irradiation (blue LEDs: λmax = 425 nm) for 2 h. As a

On the mechanism of photocatalytic reactions with eosin Y

• Michal Majek,
• Fabiana Filace and
• Axel Jacobi von Wangelin

Beilstein J. Org. Chem. 2014, 10, 981–989, doi:10.3762/bjoc.10.97

• push the acid–base equilibria of the catalytic amounts of eosin Y in either direction. The spirocyclic form EY1 contains an interrupted conjugation of the fluorone ring system and thus would be photocatalytically inactive under visible light irradiation. The neutral form EY2 exhibits only weak

Visible-light photoredox catalysis enabled bromination of phenols and alkenes

• Yating Zhao,
• Zhe Li,
• Chao Yang,
• Run Lin and
• Wujiong Xia

Beilstein J. Org. Chem. 2014, 10, 622–627, doi:10.3762/bjoc.10.53

• liquid bromine. Results and Discussion Our initial investigation was carried out on protected 4-methoxyphenol 1a and CBr4 in dried CH3CN in the presence of Ru(bpy)3Cl2 (5.0 mol %) with visible light irradiation (blue LEDs, λmax = 435 nm) for 6 hours. The corresponding 2-bromo-4-methoxyphenol (2a) was

• photocatalyst or the light source did not afford the desired product 2a. Therefore, the reaction conditions of CBr4 (1 equiv) in dried CH3CN in the presence of Ru(bpy)3Cl2 (5.0 mol %) with visible light irradiation (blue LEDs, λmax = 435 nm) and open to air were utilized to test the scope of the reaction. With

• could be prepared from the same starting materials in two steps (Table 2). We also conducted a control experiment by reacting stilbene with CBr4 (1 equiv) in dry CH3CN in the presence of Ru(bpy)3Cl2 (5.0 mol %) with visible-light irradiation (blue LEDs, λmax = 435 nm) for 72 hours, which led to the anti

Metal-free aerobic oxidations mediated by N-hydroxyphthalimide. A concise review

• Lucio Melone and
• Carlo Punta

Beilstein J. Org. Chem. 2013, 9, 1296–1310, doi:10.3762/bjoc.9.146

• the photocatalytic oxidative activation of NHPI by graphitic carbon nitride (g-C3N4) and visible light irradiation [65]. g-C3N4, the most stable allotrope of carbon nitride, is a two-dimensional polymer with a tri-s-triazine ring unit and a π-conjugated layered structure similar to graphene. It is a