Red light excitation: illuminating photocatalysis in a new spectrum

• Lucas Fortier,
• Corentin Lefebvre and
• Norbert Hoffmann

Beilstein J. Org. Chem. 2025, 21, 296–326, doi:10.3762/bjoc.21.22

• advantageous for large-scale applications, offering enhanced safety and operational simplicity. Traditionally, research in this field has focused on metal-based photocatalysts, particularly those based on transition metals like ruthenium and osmium due to their intrinsic photophysical properties. However, with

• diverse catalyst types and applications. The first section is dedicated to metal-based photocatalysts. Complexes involving metals such as osmium and ruthenium, have dominated red-light photoredox catalysis because of their ability to absorb low-energy photons and sustain redox cycles via stable excited

• catalysis in recent years not only with heavy metals such as ruthenium and iridium [1][2][3][4][5], but also with lighter elements [6][7][8]. This field of light-mediated organic transformations relies on the use of a photocatalyst to promote radical reactions through electron transfer between this former

Dioxazolones as electrophilic amide sources in copper-catalyzed and -mediated transformations

• Seungmin Lee,
• Minsuk Kim,
• Hyewon Han and
• Jongwoo Son

Beilstein J. Org. Chem. 2025, 21, 200–216, doi:10.3762/bjoc.21.12

• electrophiles in various nucleophilic transformations due to their susceptibility to rapid decomposition into the corresponding isocyanates (Scheme 1a) [2][3]. They have attracted increasing interest as electrophilic amide sources in amidation using transition-metal catalysts such as ruthenium, rhodium, and

Advances in radical peroxidation with hydroperoxides

• Oleg V. Bityukov,
• Pavel Yu. Serdyuchenko,
• Andrey S. Kirillov,
• Gennady I. Nikishin,
• Vera A. Vil’ and
• Alexander O. Terent’ev

Beilstein J. Org. Chem. 2024, 20, 2959–3006, doi:10.3762/bjoc.20.249

• catalytic system based on ruthenium salts [72][73]. The C(sp3)–H bond at the amides 76 was functionalized with the tert-butylperoxy radical under the action of the TBAI/TBHP system (Scheme 27) [74]. The target amido-peroxides 77 were synthesized in high yields. The authors proposed that the process begins

• carried out as part of the investigation of the enzymatic function of cytochrome P-450 with low valent ruthenium complex catalysts. Various phenols 86 bearing para-substituents were transformed into the corresponding tert-butyldioxy dienones 87 smoothly using RuCl2(PPh3)3 as the catalyst (Scheme 31) [83

• ][84][85]. The authors rationalized that RuCl2(PPh3)3 reacts with TBHP to give the (alkylperoxido)ruthenium(II) complex, which subsequently undergoes heterolytic cleavage of the O–O bond to form the (oxido)ruthenium(IV) species. HAT from the phenols by Ru(IV)=O intermediate leads to the phenoxyl

Synthesis of fluoroalkenes and fluoroenynes via cross-coupling reactions using novel multihalogenated vinyl ethers

• Yukiko Karuo,
• Keita Hirata,
• Atsushi Tarui,
• Kazuyuki Sato,
• Kentaro Kawai and
• Masaaki Omote

Beilstein J. Org. Chem. 2024, 20, 2691–2703, doi:10.3762/bjoc.20.226

• reagents have been developed. These reagents are easily being converted into multisubstituted fluoroalkenes through cross-coupling using palladium, nickel, copper, ruthenium, and manganese catalysts [26][27][28][29][30][31][32][33][34][35][36][37][38][39][40][41]. Hosoya and Niwa et al. published the

A review of recent advances in electrochemical and photoelectrochemical late-stage functionalization classified by anodic oxidation, cathodic reduction, and paired electrolysis

• Nian Li,
• Ruzal Sitdikov,
• Ajit Prabhakar Kale,
• Joost Steverlynck,
• Bo Li and
• Magnus Rueping

Beilstein J. Org. Chem. 2024, 20, 2500–2566, doi:10.3762/bjoc.20.214

• nitrogen-centered radical (Scheme 37). 1.3.4 Ru-assisted anodic oxidation. A ruthenium electrocatalyzed mono- and diacetoxylation of aniline derivatives via a C(sp2)–H functionalization was developed by Zhong and coworkers [51]. This transformation requires the presence of a removable directing group

• the active Ru(II) species, completing the catalytic cycle (Scheme 38). This approach underlines the potential of ruthenium catalysis in achieving site-selective functionalization of complex molecules, thereby expanding the toolkit available for organic synthesis and drug development. 1.3.5 Rh-assisted

• anodic oxidation. In addition to ruthenium-catalyzed electrochemically mediated C–H functionalizations, several groups have also explored rhodium-catalyzed anodic oxidation reactions [52][53]. Wen, Zhang, Xu, and colleagues described an efficient method for the phosphorylation of aryl substrates

Visible-light-mediated flow protocol for Achmatowicz rearrangement

• Joachyutharayalu Oja,
• Sanjeev Kumar and
• Srihari Pabbaraja

Beilstein J. Org. Chem. 2024, 20, 2493–2499, doi:10.3762/bjoc.20.213

• platforms, we herein present a photo-flow platform for Achmatowicz reactions. A novel photo-flow solar panel reactor was fabricated to test and validate the Achmatowicz rearrangement reaction (Figure S1, Supporting Information File 1), and the reaction conditions were optimized with a ruthenium catalyst. As

Multicomponent syntheses of pyrazoles via (3 + 2)-cyclocondensation and (3 + 2)-cycloaddition key steps

• Ignaz Betcke,
• Alissa C. Götzinger,
• Maryna M. Kornet and
• Thomas J. J. Müller

Beilstein J. Org. Chem. 2024, 20, 2024–2077, doi:10.3762/bjoc.20.178

Synthetic applications of the Cannizzaro reaction

• Bhaskar Chatterjee,
• Dhananjoy Mondal and
• Smritilekha Bera

Beilstein J. Org. Chem. 2024, 20, 1376–1395, doi:10.3762/bjoc.20.120

• intramolecular Cannizzaro reaction (Scheme 7) [76]. Lewis acid-catalyzed intermolecular Cannizzaro reactions Kim et al. succeeded in the transformation of aromatic aldehydes 16 to the corresponding alcohols 17 using ruthenium catalysis in the presence of KOH and dioxane as solvent (Scheme 8). The reaction

• yields to the corresponding alcohols 17 and acids 18 (Scheme 12). Santilli et al. demonstrated a dehydrogenative protocol for the synthesis of carboxylic acids 21 from primary alcohols 19 employing a ruthenium p-cymene complex (20) in the presence of a suitable hydroxide [81]. Both primary aliphatic

• mechanism. Chiral Fe catalysts-mediated enantioselective Cannizzaro reaction. Ruthenium-catalyzed Cannizzaro reaction of aromatic aldehydes. MgBr2·Et2O-assisted Cannizzaro reaction of aldehydes. LiBr-catalyzed intermolecular Cannizzaro reaction of aldehydes. γ-Alumina as a catalyst in the Cannizzaro

Manganese-catalyzed C–C and C–N bond formation with alcohols via borrowing hydrogen or hydrogen auto-transfer

• Mohd Farhan Ansari,
• Atul Kumar Maurya,
• Abhishek Kumar and
• Saravanakumar Elangovan

Beilstein J. Org. Chem. 2024, 20, 1111–1166, doi:10.3762/bjoc.20.98

• achieving both selective dehydrogenation and hydrogenation is highly important. A typical BH process is demonstrated in Scheme 1. Several precious transition-metal catalysts have been used successfully in this area, including iridium, rhodium, ruthenium, and osmium [4]. However, these noble metals are toxic

Switchable molecular tweezers: design and applications

• Pablo Msellem,
• Maksym Dekthiarenko,
• Nihal Hadj Seyd and
• Guillaume Vives

Beilstein J. Org. Chem. 2024, 20, 504–539, doi:10.3762/bjoc.20.45

(E,Z)-1,1,1,4,4,4-Hexafluorobut-2-enes: hydrofluoroolefins halogenation/dehydrohalogenation cascade to reach new fluorinated allene

• Nataliia V. Kirij,
• Andrey A. Filatov,
• Yurii L. Yagupolskii,
• Sheng Peng and
• Lee Sprague

Beilstein J. Org. Chem. 2024, 20, 452–459, doi:10.3762/bjoc.20.40

• significantly. One of the new and budding directions in recent years is the stereoselective olefin metathesis processes based on catalysis by complexes of molybdenum, tungsten and ruthenium [3][4][5]. The first publications have recently appeared that molybdenum complexes can catalyze cross-metathesis of butene

Application of N-heterocyclic carbene–Cu(I) complexes as catalysts in organic synthesis: a review

• Nosheen Beig,
• Varsha Goyal and
• Raj K. Bansal

Beilstein J. Org. Chem. 2023, 19, 1408–1442, doi:10.3762/bjoc.19.102

• multifunctional catalytic system 142 incorporating ruthenium nanoparticles (RuNPS) and an NHC–Cu–Cl complex supported on silica (Scheme 56). The catalyst, Ru@SiO2–[Cu(NHC)] was successfully applied to a one-pot tandem A3 reaction of an aldehyde, alkyne, and secondary amine followed by hydrogenation of the

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

• catalysts in an acetonitrile/water mixture [46]. They used combinations of deuterated solvents and 1H NMR spectroscopy to confirm that water was the main source of the protons for the regeneration. Furthermore, they successfully replaced ruthenium photosensitizers with organic dyes so that the system used

• systems and photosensitizers to enable direct electron transfer between them. In contrast to the system of Domen where the photoexcitation only occurs at the Al-SrTiO3 particle [53], the system developed by Ishitani included a second ruthenium chromophore linked the TaON particle to a ruthenium carbonyl

• catalyst [56]. This allowed the electron to be promoted by 2 photon absorption events, making it a Z-scheme. It can be argued that the linking ruthenium chromophore was acting as a redox mediator. Rather than using water as the sacrificial donor in this work, they used methanol which can be produced by

Strategies in the synthesis of dibenzo[b,f]heteropines

• David I. H. Maier,
• Barend C. B. Bezuidenhoudt and
• Charlene Marais

Beilstein J. Org. Chem. 2023, 19, 700–718, doi:10.3762/bjoc.19.51

• prepared by Wittig methylenation of commercially available bis(2-formylphenyl) ether (119), whereas a formylation–Wittig methylenation sequence of commercial diphenylsulfone (120) and protected bis(2-bromophenyl)amine 121 afforded the S- and N-tethered diene, respectively. Ruthenium (2nd generation Hoveyda

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

• conjugate alkynylation and consecutive aldol addition (Scheme 49) [91]. The chiral ruthenium complex C2 (Phebox-type)-catalyzed procedure delivered β-hydroxyketone derivatives 192 having α-propargyl groups in good yields, however, only with low diastereoselectivities (up to 3:1). While the syn-diastereomers

C3-Alkylation of furfural derivatives by continuous flow homogeneous catalysis

• Grédy Kiala Kinkutu,
• Catherine Louis,
• Myriam Roy,
• Juliette Blanchard and
• Julie Oble

Beilstein J. Org. Chem. 2023, 19, 582–592, doi:10.3762/bjoc.19.43

• .19.43 Abstract The C3-functionalization of furfural using homogeneous ruthenium catalysts requires the preinstallation of an ortho-directing imine group, as well as high temperatures, which did not allow scaling up, at least under batch conditions. In order to design a safer process, we set out to

• formation of ruthenium aggregates [43]. We therefore propose that the active species is a mononuclear carbonyl complex in which the ruthenium is coordinated to the two nitrogen atoms of the directing group (amino-imine). Preheating for 5 minutes at 130 °C would generate it from [Ru3(CO)11(L)], which would

• therefore be more accurate to consider as a precatalyst (Scheme 4, path b). The mononuclear complex would then initiate the alkylation reaction at 180 °C following elementary steps previously determined by DFT [21]. Conversely, a high starting temperature would favor the formation of ruthenium aggregates

Transition-metal-catalyzed domino reactions of strained bicyclic alkenes

• Austin Pounder,
• Eric Neufeld,
• Peter Myler and
• William Tam

Beilstein J. Org. Chem. 2023, 19, 487–540, doi:10.3762/bjoc.19.38

• derivative 98j in good diastereoselectivity. Ruthenium-catalyzed reactions In 2006, the Tam laboratory investigated the Ru-catalyzed cyclization of oxabenzonorbornene derivatives 30 with propargylic alcohols 99 for the synthesis of isochromenes 100 (Scheme 18) [55]. After coordination of the Ru-center to the

• cationic active ruthenium species, the authors noted the use of [Cp*Ru(CH3CN)3]PF6 as the precatalyst produced the cyclopropanated bicyclic alkene adducts exclusively. This contrasts with Tam’s report (Scheme 18) [55] which found cationic Ru species formed the isochromene 100 preferentially which may be

• state, followed by coordination to the alkyne generates intermediate 109. Migratory insertion of the alkyne results in the ruthenacycle 110. Subsequent reductive elimination generates putative allyl vinyl ether 111 and regenerates the active ruthenium complex. The allyl vinyl ether intermediate

CuAAC-inspired synthesis of 1,2,3-triazole-bridged porphyrin conjugates: an overview

• Dileep Kumar Singh

Beilstein J. Org. Chem. 2023, 19, 349–379, doi:10.3762/bjoc.19.29

• dye loading of the corresponding solar cell. Recently, Chauhan and co-workers [52] demonstrated a click-chemistry-inspired synthesis of porphyrin-meso-triazole-ruthenium(II) conjugates, as shown in Scheme 22. First, the porphyrin conjugates 111a,b (inverse tri-py) and 115a,b (regular tri-py) were

• -triazole-ruthenium(II) conjugates 112a,b and 116a,b in 18–20% yield. Their photophysical and electrochemical studies revealed that the orbital energies depend on the ligands/linker, connecting pattern of linkers, and the presence of Zn metal ions in the porphyrin core. Ligand exchange studies also

• diporphyrin conjugates 107 and 108. Synthesis of porphyrin-ruthenium (II) conjugates 112a,b and 116a,b. Reaction conditions: (i) Zn(OAc)2, CHCl3/MeOH (ii) CuSO4·5H2O, sodium ascorbate, DIPEA, CH2Cl2/EtOH/H2O, 50 °C. Synthesis of meso-triazole-linked porphyrin dyad 119 and triad 121. Synthesis of di-triazole

Inline purification in continuous flow synthesis – opportunities and challenges

• Jorge García-Lacuna and
• Marcus Baumann

Beilstein J. Org. Chem. 2022, 18, 1720–1740, doi:10.3762/bjoc.18.182

• purifications can be an easier and more effective alternative. An efficient method to homogeneously scavenge a ruthenium complex used in a metathesis reaction was described by Grela and co-workers on a 60 g scale [89]. The use of heterogeneous scavenger columns in flow mode is sometimes criticized. If the final

Ionic multiresonant thermally activated delayed fluorescence emitters for light emitting electrochemical cells

• Merve Karaman,
• Abhishek Kumar Gupta,
• Subeesh Madayanad Suresh,
• Tomas Matulaitis,
• Lorenzo Mardegan,
• Daniel Tordera,
• Henk J. Bolink,
• Sen Wu,
• Stuart Warriner,
• Ifor D. Samuel and
• Eli Zysman-Colman

Beilstein J. Org. Chem. 2022, 18, 1311–1321, doi:10.3762/bjoc.18.136

• and emission takes place within the intrinsic region [2][3][4][5][6]. Two families of widely investigated emitters for LEECs are ionic transition metal complexes (iTMCs) [7][8][9][10] and conjugated polymers (CPs) [4]. From the early use of ruthenium(II) complexes, a significant amount of research has

Electrochemical Friedel–Crafts-type amidomethylation of arenes by a novel electrochemical oxidation system using a quasi-divided cell and trialkylammonium tetrafluoroborate

• Hisanori Senboku,
• Mizuki Hayama and
• Hidetoshi Matsuno

Beilstein J. Org. Chem. 2022, 18, 1040–1046, doi:10.3762/bjoc.18.105

• -acyliminium ions in chemical methods has been generally accomplished by the reaction of amides with chemical oxidants, such as peroxides and persulfates at high temperature (path a in Scheme 1) [10][11][12][13]. A metal catalyst or a photocatalyst consisting of metals, such as ruthenium or iridium, is also

Synthetic strategies for the preparation of γ-phostams: 1,2-azaphospholidine 2-oxides and 1,2-azaphospholine 2-oxides

• Jiaxi Xu

Beilstein J. Org. Chem. 2022, 18, 889–915, doi:10.3762/bjoc.18.90

• -Allylamino-1,5-dihydro-1,2-azaphosphole 2-oxide derivatives 95 were prepared in 13–76% yield from N,N’-diallyl-vinylphosphonodiamides 94 via the Grubbs ruthenium-catalyzed RCM. N,N’-Dicinnamyl-N,N’-dimethyl-vinylphosphonodiamide (94a) (R = R’ = H) generated the 2-(N-methyl-N-cinnamylamino)-1,5-dihydro-1,2

Synthesis of odorants in flow and their applications in perfumery

• Merlin Kleoff,
• Paul Kiler and
• Philipp Heretsch

Beilstein J. Org. Chem. 2022, 18, 754–768, doi:10.3762/bjoc.18.76

• 20 min at 80 °C using 1 mol % of catalyst 59 [52]. Due to the fact that ethylene formed in the ring-closing metathesis can result in the formation of unstable ruthenium methylidene species, causing degeneration of the metathesis catalyst, the continuous removal of ethylene from the reaction mixture

• can be highly beneficial. Therefore, Skowerski and co-workers constructed a tube-in-tube reactor for the ring-closing metathesis of dienes 62 and 63 to macrocycles 65 or 66, respectively, mediated by ruthenium catalyst 64 (Scheme 15) [53]. The substrate and the catalyst are mixed in a Q-piece and

• ]. Solutions of dialkene 67 and the Z-selective ruthenium catalyst 68 in 1,2-dichloroethane are mixed and pumped through a tube-in-tube reactor continuously removing the ethylene formed in the ring-closing metathesis. At 70 °C and with a residence time of 3 h, civetone (69) is formed in 44% isolated yield with

Inductive heating and flow chemistry – a perfect synergy of emerging enabling technologies

• Conrad Kuhwald,
• Sibel Türkhan and
• Andreas Kirschning

Beilstein J. Org. Chem. 2022, 18, 688–706, doi:10.3762/bjoc.18.70

• ruthenium increased the catalytic activity and allowed the catalytic process to be carried out at lower reaction temperatures, which was explained by the fact that the surface temperature of the nanoparticles was in fact significantly higher than 200 °C. It was also not necessary to implement an additional

Heteroleptic metallosupramolecular aggregates/complexation for supramolecular catalysis

• Prodip Howlader and
• Michael Schmittel

Beilstein J. Org. Chem. 2022, 18, 597–630, doi:10.3762/bjoc.18.62

• metal–ligand motifs often center about iridium, ruthenium, rhodium etc. [25], the dynamic ones are constructed using copper(I), zinc(II), cadmium(II), iron(II), palladium(II), etc. as metal ions due to their more rapid ligand exchange rates [24][25][26]. The strategies to prepare inert vs dynamic