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

Synthesis of 3,4,5-trisubstituted isoxazoles in water via a [3 + 2]-cycloaddition of nitrile oxides and 1,3-diketones, β-ketoesters, or β-ketoamides

• Md Imran Hossain,
• Md Imdadul H. Khan,
• Seong Jong Kim and
• Hoang V. Le

Beilstein J. Org. Chem. 2022, 18, 446–458, doi:10.3762/bjoc.18.47

• highly substituted non-terminal alkynes does not proceed with copper catalysts at room temperature. As an alternative, the usage of ruthenium(II) catalysts enables the reaction to proceed smoothly at room temperature and produces high yields and regioselectivity for both, 3,5-disubstituted and 3,4,5

• needed to be synthesized independently [23]. While ruthenium(II) and palladium catalysts are useful, they are expensive and environmentally unfriendly. The dehalogenation of hydroximoyl chlorides in the presence of a strong base to generate nitrile oxides and a follow-up cycloaddition with 1,3-diketones

Menadione: a platform and a target to valuable compounds synthesis

• Acácio S. de Souza,
• Ruan Carlos B. Ribeiro,
• Dora C. S. Costa,
• Fernanda P. Pauli,
• David R. Pinho,
• Matheus G. de Moraes,
• Fernando de C. da Silva,
• Luana da S. M. Forezi and
• Vitor F. Ferreira

Beilstein J. Org. Chem. 2022, 18, 381–419, doi:10.3762/bjoc.18.43

• ) complexes showing the best catalytic activities with high selectivity compared to the Pt(II) complex, leading to 95–99% conversion and 60–65% selectivity (Table 1, entry 12) [58]. Sönmez and co-workers applied mononuclear complexes of ruthenium(III), chromium(III), and iron(III) with Schiff base ligands as

• )ruthenium(II) dichloride as catalyst. Then, a BF3·OEt2-catalzyed migration of the methyl group to the C-2 position and removal of the tert-butoxy group in a 1,1,1,3,3,3-hexafluoroisopropanol (HFIP)/toluene mixture afforded 2-methyl-1,4-benzoquinone (29). Finally, a Diels–Alder reaction was performed with

Ready access to 7,8-dihydroindolo[2,3-d][1]benzazepine-6(5H)-one scaffold and analogues via early-stage Fischer ring-closure reaction

• Irina Kuznetcova,
• Felix Bacher,
• Daniel Vegh,
• Hsiang-Yu Chuang and
• Vladimir B. Arion

Beilstein J. Org. Chem. 2022, 18, 143–151, doi:10.3762/bjoc.18.15

• enzyme active sites and/or improved selectivity [7]. One of the main drawbacks of paullones is their poor aqueous solubility. Therefore, in an attempt to overcome this shortcoming, the paullone backbone A was decorated with functional groups and coordinated to metal ions. Ruthenium(II), osmium(II), and

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

• . The ability to exhibit multiple oxidation states increased the demand of ruthenium in the field of catalysis. These cyanation reactions have wide application in pharmacological and biological fields. This review gives an overview of the ruthenium-catalyzed cyanation reactions covering literature up to

• 2021. Keywords: cyanation; nitriles; photocatalyst; ruthenium; tertiary amines; Introduction Nitriles are a major class of organic compounds having wide significance in materials science, agrochemical and pharmaceutical industry [1]. They are the privileged compounds finding broad applications in

• . Commonly used metallic cyanating agents include K4Fe(CN)6, CuCN, KCN, NaCN, TMSCN etc. Ruthenium-catalyzed reactions have gained significant attention in recent times [26]. Ruthenium has the ability to show a large number of oxidation states, and thus a large number of complexes can be prepared using this

Me₃Al-mediated domino nucleophilic addition/intramolecular cyclisation of 2-(2-oxo-2-phenylethyl)benzonitriles with amines; a convenient approach for the synthesis of substituted 1-aminoisoquinolines

• Krishna M. S. Adusumalli,
• Lakshmi N. S. Konidena,
• Hima B. Gandham,
• Krishnaiah Kumari,
• Krishna R. Valluru,
• Satya K. R. Nidasanametla,
• Venkateswara R. Battula and
• Hari K. Namballa

Beilstein J. Org. Chem. 2021, 17, 2765–2772, doi:10.3762/bjoc.17.186

• amidines with alkynes catalyzed by either rhodium or ruthenium [55][56][57], or a metal-catalyzed aminative cyclization of 2-alkynylbenzonitriles with secondary amines [58]. Despite the advantages associated with the aforementioned protocols such as the functional group tolerance and huge substrate scope

Visible-light-mediated copper photocatalysis for organic syntheses

• Yajing Zhang,
• Qian Wang,
• Zongsheng Yan,
• Donglai Ma and
• Yuguang Zheng

Beilstein J. Org. Chem. 2021, 17, 2520–2542, doi:10.3762/bjoc.17.169

• renewable energy and green chemistry for many years. Ruthenium and iridium, which can be used as photoredox catalysts, are expensive and scarce in nature. Thus, the further development of catalysts based on these transition metals is discouraged. Alternative photocatalysts based on copper complexes are

• ; however, they suffer from relatively poor photostability [14][15][16]. Transition-metal-photoredox catalysts, such as ruthenium and iridium polypyridyl complexes, exhibit high redox potentials, long excited state lifetimes, and strong absorption [17][18][19][20]. However, high cost and their scarcity

• discourage development of ruthenium and iridium-based catalysts [21]. Copper salts have become popular materials for photoredox catalysts due to their abundance, low cost, and ability to provide strong photoexcited reducing power [21][22][23][24]. In this review, the different catalysis mechanisms between

Strategies for the synthesis of brevipolides

• Yudhi D. Kurniawan and
• A'liyatur Rosyidah

Beilstein J. Org. Chem. 2021, 17, 2399–2416, doi:10.3762/bjoc.17.157

• -carbon precursor for the synthesis. The forward synthesis transformed 2-acetylfuran (20) to its corresponding alcohol 21 through an asymmetric transfer hydrogenation catalyzed by a ruthenium complex (0.5 mol %) in 98% yield with 95% ee (Scheme 2). The azeotropic mixture of HCO2H/Et3N 5:2 was employed as

Photoredox catalysis in nickel-catalyzed C–H functionalization

• Lusina Mantry,
• Rajaram Maayuri,
• Vikash Kumar and
• Parthasarathy Gandeepan

Beilstein J. Org. Chem. 2021, 17, 2209–2259, doi:10.3762/bjoc.17.143

• (sp3)‒H bonds with aryl tosylates/triflates 11. The relatively less expensive ruthenium photocatalyst Ru(bpy)3Cl2·6H2O was found to be optimal for primary C(sp3)‒H arylations (Scheme 7a), whereas Ir[dF(CF3)ppy]2(dtbbpy)PF6 was the effective photocatalyst for the arylation of secondary C(sp3)‒H bonds

Chemical syntheses and salient features of azulene-containing homo- and copolymers

• Vijayendra S. Shetti

Beilstein J. Org. Chem. 2021, 17, 2164–2185, doi:10.3762/bjoc.17.139

• aqueous acid solution. Further, the coordination of polymers 37 and 39 to a multinuclear Ru cluster was investigated by the same group [32]. The organometallic complexes 40–43 were synthesized by treating polymers 37 and 39 with Ru3(CO)12 in refluxing xylene (Scheme 9). The ruthenium content in these

• complexes can be varied by changing the ratio of reactants during the reaction. The 1H NMR chemical shift values of the azulene unit were used as a tool to determine the extent of ruthenium coordination to the azulene units in the polymer backbone as the coordinated azulene displays upfield-shifted

• resonance signals when compared to free azulenes. The absorption and electrochemical studies conducted on these complexes 40–43 revealed that their properties could be tuned by varying the ruthenium content in the polymer. A higher ruthenium content was inducing a larger blue-shift of the absorption bands