Optimizing reaction conditions for the light-driven hydrogen evolution in a loop photoreactor

• Pengcheng Li,
• Daniel Kowalczyk,
• Johannes Liessem,
• Mohamed M. Elnagar,
• Dariusz Mitoraj,
• Radim Beranek and
• Dirk Ziegenbalg

Beilstein J. Org. Chem. 2024, 20, 74–91, doi:10.3762/bjoc.20.9

• ) processes, and photocatalysis. Upon upscaling, both PV-E and PEC reactors exhibit pH gradients at electrodes and elevated solution electrical resistivity. These challenges arise from the substantial separation between reduction and oxidation sites, alongside mass transport restrictions in the liquid phase

Aromatic systems with two and three pyridine-2,6-dicarbazolyl-3,5-dicarbonitrile fragments as electron-transporting organic semiconductors exhibiting long-lived emissions

• Karolis Leitonas,
• Brigita Vigante,
• Dmytro Volyniuk,
• Audrius Bucinskas,
• Pavels Dimitrijevs,
• Sindija Lapcinska,
• Pavel Arsenyan and
• Juozas Vidas Grazulevicius

Beilstein J. Org. Chem. 2023, 19, 1867–1880, doi:10.3762/bjoc.19.139

• their application in photocatalysis has been recently published [9]. 2,6-Bis(4-cyanophenyl)-4-(9-phenyl-9H-carbazol-3-yl)pyridine-3,5-dicarbonitrile) exhibits two aggregate states in aqueous dispersions: amorphous nanospheres and ordered nanofibers with π–π molecular stacking. The nanofibers promoted

Recent advancements in iodide/phosphine-mediated photoredox radical reactions

• Tinglan Liu,
• Yu Zhou,
• Junhong Tang and
• Chengming Wang

Beilstein J. Org. Chem. 2023, 19, 1785–1803, doi:10.3762/bjoc.19.131

• remarkable advances not only highlighted the synthetic potential of photocatalysis but also served as inspiration for future developments of low-cost photocatalysis based on other non-covalent interactions. The simplicity, practicality, and broad substrate scope demonstrated by these approaches further

• emphasized their significance in facilitating the synthesis of diverse compounds and paving the way for further advancements in the field of photocatalysis. The highly efficient construction of carbon–heteroatom (C–X) bonds is of significant importance in the fields of natural products, pharmaceuticals, and

• hydrogenation or hydrogen transfer [40], electrocatalysis coupled with water oxidation [41], and sustained visible-light-induced photocatalysis [42]. Among the different strategies available, the use of a mild photocatalytic process involving hole-driven hydrogen transfer with hydrogen donors or hole scavengers

Selectivity control towards CO versus H₂ for photo-driven CO₂ reduction with a novel Co(II) catalyst

• Lisa-Lou Gracia,
• Philip Henkel,
• Olaf Fuhr and
• Claudia Bizzarri

Beilstein J. Org. Chem. 2023, 19, 1766–1775, doi:10.3762/bjoc.19.129

• chosen solvent for photocatalysis. The absorption profile evokes the structured band of the free ligand BzQuTr [42], with two intense π–π* ligand-centered transitions at circa 319 nm and 330 nm (Figure 3). The pink solid dissolves as an intense blue DMA solution. Nevertheless, the d–d transitions

Organic thermally activated delayed fluorescence material with strained benzoguanidine donor

• Alexander C. Brannan,
• Elvie F. P. Beaumont,
• Nguyen Le Phuoc,
• George F. S. Whitehead,
• Mikko Linnolahti and
• Alexander S. Romanov

Beilstein J. Org. Chem. 2023, 19, 1289–1298, doi:10.3762/bjoc.19.95

• fluorescence [1][2][3]. Organic TADF emitters have gained substantial attention in recent years for their prospective application in organic light-emitting diodes (OLEDs), photocatalysis, bioimaging, and sensors [4][5][6]. The ability to harvest both singlet and triplet excitons enable organic TADF emitters to

Radical ligand transfer: a general strategy for radical functionalization

• David T. Nemoto Jr,
• Kang-Jie Bian,
• Shih-Chieh Kao and
• Julian G. West

Beilstein J. Org. Chem. 2023, 19, 1225–1233, doi:10.3762/bjoc.19.90

• ; photocatalysis; radicals; Introduction The behavior of alkyl radicals has been studied rigorously for decades, though only recently have these come to be widely viewed as selective and useful synthetic intermediates [1][2][3][4]. This sea change has been driven by innovations in both the generation and

• quenched and functionalized through RLT. II: Modern catalysts developed for RLT catalysis. The incorporation of RLT catalysis in ATRA photocatalysis. I: The reported method is compatible with nucleophilic sources of chlorine groups, azide groups, and thioisocyanate groups. II: The proposed mechanism for

Enabling artificial photosynthesis systems with molecular recycling: A review of photo- and electrochemical methods for regenerating organic sacrificial electron donors

• Grace A. Lowe

Beilstein J. Org. Chem. 2023, 19, 1198–1215, doi:10.3762/bjoc.19.88

• sacrificial electron donors, and for researchers interested in designing new redox mediator and recyclable electron donor species. Keywords: artificial photosynthesis; photocatalysis; redox couple; sacrificial electron donor; solar fuels; Introduction Artificial photosynthesis research has resulted in the

• donors used in photoreduction catalysis for artificial photosynthesis. Specifically, organic electron or hydride donors usually applied in molecular photocatalysis. 2. Survey the literature from different fields and present a sample of potentially recyclable electron donors for artificial photosynthesis

• photocatalysis. Cyclic voltammetry carried out in standard conditions for mimicking an acetonitrile system had not been close enough to the catalytic conditions to get the required redox potentials. The difference between the oxidation potential of a sacrificial donor and the reduction potential of the excited

Exploring the role of halogen bonding in iodonium ylides: insights into unexpected reactivity and reaction control

• Carlee A. Montgomery and
• Graham K. Murphy

Beilstein J. Org. Chem. 2023, 19, 1171–1190, doi:10.3762/bjoc.19.86

• events. Xuan, Li and co-workers further investigated the coupling between iodonium ylides and tertiary amines, and showed that this thermal reaction could instead be initiated by blue light photocatalysis (Scheme 7) [124]. Therein, they investigated the iodoarene motif of the ylide, and while ylide 31

Photoredox catalysis harvesting multiple photon or electrochemical energies

• Mattia Lepori,
• Simon Schmid and
• Joshua P. Barham

Beilstein J. Org. Chem. 2023, 19, 1055–1145, doi:10.3762/bjoc.19.81

• conditions. In 2020, the Polyzos group also demonstrated the carbonylative amidation of aryl halides in continuous flow with the in situ-generated [Ir2]0 (Figure 19A) [79]. This multi-photon tandem photocatalysis protocol provides an elegant alternative to established classical procedures for condensing

Clauson–Kaas pyrrole synthesis using diverse catalysts: a transition from conventional to greener approach

• Dileep Kumar Singh and
• Rajesh Kumar

Beilstein J. Org. Chem. 2023, 19, 928–955, doi:10.3762/bjoc.19.71

• to reduce energy consumption and the carbon footprint. The traditional heating techniques used to synthesize compounds are being replaced by contemporary green alternative energy systems, such as photocatalysis, microwave irradiation, ultrasonic irradiation, grinding, and ball milling processes

Photoredox catalysis enabling decarboxylative radical cyclization of γ,γ-dimethylallyltryptophan (DMAT) derivatives: formal synthesis of 6,7-secoagroclavine

• Alessio Regni,
• Francesca Bartoccini and
• Giovanni Piersanti

Beilstein J. Org. Chem. 2023, 19, 918–927, doi:10.3762/bjoc.19.70

• ][32][33], modification of biomacromolecules [34], and relatively complex pharmaceutical agents [35][36][37][38]. Photocatalysis tremendously enriches the synthetic compound library, providing a precious alternative to directly modify abundant natural substrates, including biomass, which usually

Synthesis of aliphatic nitriles from cyclobutanone oxime mediated by sulfuryl fluoride (SO₂F₂)

• Xian-Lin Chen and
• Hua-Li Qin

Beilstein J. Org. Chem. 2023, 19, 901–908, doi:10.3762/bjoc.19.68

• ], Liu [35], and Yang [36] achieved similar transformations through visible-light photocatalysis. In addition, Guo [37][38] improved the protocol by using low-cost nickel and iron catalysts. However, most of these advancements mainly relied on the excellent redox potential manipulation of cyclic oxime

Enolates ambushed – asymmetric tandem conjugate addition and subsequent enolate trapping with conventional and less traditional electrophiles

• Péter Kisszékelyi and
• Radovan Šebesta

Beilstein J. Org. Chem. 2023, 19, 593–634, doi:10.3762/bjoc.19.44

Transition-metal-catalyzed C–H bond activation as a sustainable strategy for the synthesis of fluorinated molecules: an overview

• Louis Monsigny,
• Floriane Doche and
• Tatiana Besset

Beilstein J. Org. Chem. 2023, 19, 448–473, doi:10.3762/bjoc.19.35

• derivatives. Finally, the use of abundant non-noble transition metals [209][210][211] in such reactions combined or not with modern technologies (photocatalysis and electrocatalysis) is still underexplored and any advances will be of high importance especially from a sustainability point of view aiming at

NaI/PPh₃-catalyzed visible-light-mediated decarboxylative radical cascade cyclization of N-arylacrylamides for the efficient synthesis of quaternary oxindoles

• Dan Liu,
• Yue Zhao and
• Frederic W. Patureau

Beilstein J. Org. Chem. 2023, 19, 57–65, doi:10.3762/bjoc.19.5

• afforded various functionalized oxindoles featuring a C3 quaternary stereogenic center. Mechanistic experiments suggest a radical mechanism. Keywords: decarboxylative cascade cyclization; iodide catalysis; metal-free photocatalysis; oxindole; phosphine catalysis; Introduction Radical-initiated cascade

• decarboxylative radical cascade cyclization of N-arylacrylamides with various redox-active esters derived from common and/or important carboxylic acids under mild conditions. Complementary to traditional transition metal photocatalysis and organo-photocatalysis [85], the readily available and inexpensive NaI/PPh3

Combining the best of both worlds: radical-based divergent total synthesis

• Kyriaki Gennaiou,
• Antonios Kelesidis,
• Maria Kourgiantaki and
• Alexandros L. Zografos

Beilstein J. Org. Chem. 2023, 19, 1–26, doi:10.3762/bjoc.19.1

• -mediated photocatalysis (using Pd(PPh3)2Cl2 in combination with xantphos) [112] towards 244, followed by Mukaiyama hydration with the aid of Mn(dpm)3, dioxygen, and PhSiH3 for the synthesis of kadsuphilin N (234). Conclusion The utility of radical retrosynthetic disconnections in natural product synthesis

Redox-active molecules as organocatalysts for selective oxidative transformations – an unperceived organocatalysis field

• Elena R. Lopat’eva,
• Igor B. Krylov,
• Dmitry A. Lapshin and
• Alexander O. Terent’ev

Beilstein J. Org. Chem. 2022, 18, 1672–1695, doi:10.3762/bjoc.18.179

• of ethylbenzene and CH-fluorination of aldehydes catalyzed by N-hydroxybenzimidazoles, precursors of corresponding N-oxyl radicals. Mixed hetero-/homogeneous TiO2/N-hydroxyimide photocatalysis in the selective benzylic oxidation. Electrochemical benzylic iodination and benzylation of pyridine by

Mechanochemical bottom-up synthesis of phosphorus-linked, heptazine-based carbon nitrides using sodium phosphide

• Blaine G. Fiss,
• Georgia Douglas,
• Michael Ferguson,
• Jorge Becerra,
• Jesus Valdez,
• Trong-On Do,
• Tomislav Friščić and
• Audrey Moores

Beilstein J. Org. Chem. 2022, 18, 1203–1209, doi:10.3762/bjoc.18.125

• -PCN300) show a reduction in photoluminescent recombination, as well as a nearly two-time increase in photocurrent under broad spectrum irradiation, which are appealing properties for photocatalysis. Keywords: carbon nitride; density functional theory; mechanochemistry; phosphorus; photochemistry

Heterogeneous metallaphotoredox catalysis in a continuous-flow packed-bed reactor

• Wei-Hsin Hsu,
• Susanne Reischauer,
• Peter H. Seeberger,
• Bartholomäus Pieber and
• Dario Cambié

Beilstein J. Org. Chem. 2022, 18, 1123–1130, doi:10.3762/bjoc.18.115

• synthesis [3]. The adoption of flow chemistry ensured short photon path lengths and overcame issues related to scalability and productivity caused by the limited light penetration in large batch reactors (Lambert–Beer law), thereby making photocatalysis a promising option for industrially relevant processes

• . Results and Discussion Reactor assembly and model reaction We started our investigations by preparing a packed-bed reactor using a glass column (6.6 mm i.d., 100 mm length) that can be used in a dedicated setup for heterogeneous flow photocatalysis carried out in a commercial photochemical flow reactor

Synthesis of α-(perfluoroalkylsulfonyl)propiophenones: a new set of reagents for the light-mediated perfluoroalkylation of aromatics

• Durbis J. Castillo-Pazos,
• Juan D. Lasso and
• Chao-Jun Li

Beilstein J. Org. Chem. 2022, 18, 788–795, doi:10.3762/bjoc.18.79

• perfluorinated chains into aromatic rings have been developed since the first reports of such transformation by George Tiers in 1960, and McLoughlin and Thrower in 1969 [2][3]. Most approaches have made extensive use of organometallic chemistry, radical initiators, photocatalysis, electrochemistry, and more

Comparative study of thermally activated delayed fluorescent properties of donor–acceptor and donor–acceptor–donor architectures based on phenoxazine and dibenzo[a,j]phenazine

• Saika Izumi,
• Prasannamani Govindharaj,
• Anna Drewniak,
• Paola Zimmermann Crocomo,
• Satoshi Minakata,
• Leonardo Evaristo de Sousa,
• Piotr de Silva,
• Przemyslaw Data and
• Youhei Takeda

Beilstein J. Org. Chem. 2022, 18, 459–468, doi:10.3762/bjoc.18.48

• organic light-emitting diodes (OLEDs) by Adachi in 2012 [2], TADF-active compounds have emerged as emitters in high-performance organic light-emitting diodes (OLEDs) [3][4][5][6][7][8], biological probes [9], photocatalysis [10], and some others [11]. Specifically, TADF-active purely organic compounds

Tetraphenylethylene-embedded pillar[5]arene-based orthogonal self-assembly for efficient photocatalysis in water

• Zhihang Bai,
• Krishnasamy Velmurugan,
• Xueqi Tian,
• Minzan Zuo,
• Kaiya Wang and
• Xiao-Yu Hu

Beilstein J. Org. Chem. 2022, 18, 429–437, doi:10.3762/bjoc.18.45

• photosynthesis and exhibited a high catalytic efficiency for the photocatalytic dehalogenation reaction of various bromoketone derivatives with good yields in short reaction time in water. Keywords: aggregation-induced emission; Förster resonance energy transfer; host–guest interaction; photocatalysis

Earth-abundant 3d transition metals on the rise in catalysis

• Nikolaos Kaplaneris and
• Lutz Ackermann

Beilstein J. Org. Chem. 2022, 18, 86–88, doi:10.3762/bjoc.18.8

• . Applications of this strategy range from late-stage functionalization to modern photocatalysis and electrocatalysis, with contributions from around the globe, including Brazil, China, Japan, Germany, India, and South Korea, among others. The increasing use of C–H activations in academic and industrial

Recent advances and perspectives in ruthenium-catalyzed cyanation reactions

• Thaipparambil Aneeja,
• Cheriya Mukkolakkal Abdulla Afsina,
• Padinjare Veetil Saranya and
• Gopinathan Anilkumar

Beilstein J. Org. Chem. 2022, 18, 37–52, doi:10.3762/bjoc.18.4

• investigated the cyanation of differently substituted 7-azaindoles and achieved excellent results. They also succeeded in applying this strategy to N-aryl-α-carbolines to synthesize the respective cyanated N-aryl-α-carboline products. 3 Photocatalyzed cyanation reactions Nowadays photocatalysis has emerged as

DABCO-promoted photocatalytic C–H functionalization of aldehydes

• Bruno Maia da Silva Santos,
• Mariana dos Santos Dupim,
• Cauê Paula de Souza,
• Thiago Messias Cardozo and
• Fernanda Gadini Finelli

Beilstein J. Org. Chem. 2021, 17, 2959–2967, doi:10.3762/bjoc.17.205

• differences are discussed. Keywords: C–H functionalization; DABCO; HAT; photocatalysis; Introduction The functionalization of inert C–H bonds is a goal pursued by chemists from decades, due to its ubiquity in organic molecules. This strategy also dismisses tiresome protecting groups and functional group

• interchanging steps, often required in traditional synthetic methodologies [1][2]. The development of photocatalysis enabled inexpensive access to C–H activation methodologies under mild conditions, with hydrogen atom transfer (HAT) reactions standing out as a main strategy [1][3][4]. The hydrogen abstractor is