A systematic review on silica-, carbon-, and magnetic materials-supported copper species as efficient heterogeneous nanocatalysts in “click” reactions

• Pezhman Shiri and
• Jasem Aboonajmi

Beilstein J. Org. Chem. 2020, 16, 551–586, doi:10.3762/bjoc.16.52

• protecting groups [12]. Later, ruthenium complexes-catalyzed alkyne–azide cycloadditions (RuAACs) regioselectively produced the opposite form of the disubstituted triazoles. Thus, a wide range of azides was reacted with diverse nonactivated terminal alkyne substrates using ruthenium complexes to generate

Efficient synthesis of 3,6,13,16-tetrasubstituted-tetrabenzo[a,d,j,m]coronenes by selective C–H/C–O arylations of anthraquinone derivatives

• Seiya Terai,
• Yuki Sato,
• Takuya Kochi and
• Fumitoshi Kakiuchi

Beilstein J. Org. Chem. 2020, 16, 544–550, doi:10.3762/bjoc.16.51

• alkyl and alkoxy substituents at the 3, 6, 13, and 16-positions was achieved based on the ruthenium-catalyzed coupling reactions of anthraquinone derivatives with arylboronates via C–H and C–O bond cleavage. The reaction sequence involving the arylation, carbonyl methylenation, and oxidative cyclization

• tetrabenzo[a,d,j,m]coronene product indicated its self-assembling behavior in CDCl3. Keywords: C–H arylation; C–O arylation; oxidative cyclization; polycyclic aromatic hydrocarbons; ruthenium catalyst; Introduction Polycyclic aromatic hydrocarbons (PAHs) and their derivatives have attracted much attention

• reactions have been increasingly utilized in recent years for the rapid expansion of the aromatic frameworks [10][11][12][13][14][15]. We have been working on the efficient syntheses of PAH derivatives based on the ruthenium-catalyzed C–H/C–O arylation reactions developed in our group [16][17][18][19][20

KOt-Bu-promoted selective ring-opening N-alkylation of 2-oxazolines to access 2-aminoethyl acetates and N-substituted thiazolidinones

• Qiao Lin,
• Shiling Zhang and
• Bin Li

Beilstein J. Org. Chem. 2020, 16, 492–501, doi:10.3762/bjoc.16.44

• synthetic chemists. However, only a few examples are reported for the synthesis of N-substituted thiazolidinones although the synthetic method of thiazolidinone was described in 1993 [16]. Frost and co-workers explored an efficient ruthenium-catalyzed O-to-S-alkyl migration of N-alkyloxazolidine-2-thiones

Recent advances in photocatalyzed reactions using well-defined copper(I) complexes

• Mingbing Zhong,
• Xavier Pannecoucke,
• Philippe Jubault and
• Thomas Poisson

Beilstein J. Org. Chem. 2020, 16, 451–481, doi:10.3762/bjoc.16.42

• organic chemistry. Despite the impressive advances reported since the renewal of the field in 2008 [2][3][4], several issues still have to be addressed. Indeed, most of the developed reactions relied on the use of organometallic complexes of expensive noble metals, such as iridium and ruthenium [5]. Even

• authors precluded a possible photocatalytic process (path II). And indeed, even though from a comparison of the redox potential of [Cu(I)(dap)2]Cl and [Ru(bpy)3]Cl2, the latter should have been capable to promote the photocatalytic reaction, the ruthenium complex was unsuccessful. Hence, to explain the

Synthesis of six-membered silacycles by borane-catalyzed double sila-Friedel–Crafts reaction

• Yafang Dong,
• Masahiko Sakai,
• Kazuto Fuji,
• Kohei Sekine and
• Yoichiro Kuninobu

Beilstein J. Org. Chem. 2020, 16, 409–414, doi:10.3762/bjoc.16.39

• silacycles. For example, the intramolecular C–H silylation of biphenylhydrosilanes can be used to prepare various silafluorene derivatives [30][31][32][33][34] and the ruthenium-catalyzed intermolecular Friedel–Crafts-type reaction of 2-phenylindole with a variety of dihydrosilanes affords indole-fused

Synthesis of 3-alkenylindoles through regioselective C–H alkenylation of indoles by a ruthenium nanocatalyst

• Abhijit Paul,
• Debnath Chatterjee,
• Srirupa Banerjee and
• Somnath Yadav

Beilstein J. Org. Chem. 2020, 16, 140–148, doi:10.3762/bjoc.16.16

• are biologically and medicinally very important compounds, and their syntheses have received considerable attention. Herein, we report the synthesis of 3-alkenylindoles via a regioselective alkenylation of indoles, catalysed by a ruthenium nanocatalyst (RuNC). The reaction tolerates several electron

• on the surface are responsible for the high catalytic efficiency of the Ru nanocatalyst. Keywords: alkenylation; C–H activation; heterogeneous catalysis; nanocatalysis; ruthenium catalysis; Introduction The synthesis of functionalised indole ring systems has received significant attention over the

• analysed by XPS, which showed peaks at 280.0 and 284.7 eV (Figure S8, Supporting Information File 1), corresponded to the 3d5/2 and 3d3/2 peak regions of ruthenium (Figure S9, Supporting Information File 1). This could be deconvoluted to the peaks for Ru(0) at 279.8 and 283.8 eV and RuO2 at 280.5 and 284.6

Progress in metathesis chemistry

• Karol Grela and
• Anna Kajetanowicz

Beilstein J. Org. Chem. 2019, 15, 2765–2766, doi:10.3762/bjoc.15.267

• by Kotha et al. [4], on artificial metalloproteins by Okuda et al. [5], on stereoretentive ruthenium dithiolate catalysts by Mauduit et al. [6], on unsymmetrical NHC ligands by Grisi et al. [7], on polymers by Kudryavtsev [8] and on polyhedral oligomeric silsesquioxanes by Pietraszuk et al. [9

Formation of alkyne-bridged ferrocenophanes using ring-closing alkyne metathesis on 1,1’-diacetylenic ferrocenes

• Celine Bittner,
• Dirk Bockfeld and
• Matthias Tamm

Beilstein J. Org. Chem. 2019, 15, 2534–2543, doi:10.3762/bjoc.15.246

• illustrated for alkyne metathesis reactions of organometallic compounds. After some stoichiometric reactions of ruthenium and rhenium half sandwich complexes [70], several reactions have been described exploiting the reactivity of acetylenic ferrocene compounds [71][72][73][74][75]. For most of these

α,ß-Didehydrosuberoylanilide hydroxamic acid (DDSAHA) as precursor and possible analogue of the anticancer drug SAHA

• Shital K. Chattopadhyay,
• Subhankar Ghosh,
• Sarita Sarkar and
• Kakali Bhadra

Beilstein J. Org. Chem. 2019, 15, 2524–2533, doi:10.3762/bjoc.15.245

• (phenylmethylene)(tricyclohexylphosphine)ruthenium, 9a] in dichloromethane at room temperature provided the CM-product 10a in a moderate yield of 41% within 16 hours. However, raising the catalyst concentration to 5 mol % and employing elevated temperature increased the yield to 56% within 6 hours. Contrarily, the

Chiral terpene auxiliaries V: Synthesis of new chiral γ-hydroxyphosphine oxides derived from α-pinene

• Anna Kmieciak and
• Marek P. Krzemiński

Beilstein J. Org. Chem. 2019, 15, 2493–2499, doi:10.3762/bjoc.15.242

• ligands that were obtained from readily available natural (1S)-β-pinene and (1S)-α-pinene [18]. We applied these ligands for the formation of the ruthenium complexes, which were successfully used as catalysts in asymmetric transfer hydrogenation of prochiral ketones. In continuation of our studies on the

Combining the Ugi-azide multicomponent reaction and rhodium(III)-catalyzed annulation for the synthesis of tetrazole-isoquinolone/pyridone hybrids

• Gerardo M. Ojeda,
• Prabhat Ranjan,
• Pavel Fedoseev,
• Lisandra Amable,
• Upendra K. Sharma,
• Daniel G. Rivera and
• Erik V. Van der Eycken

Beilstein J. Org. Chem. 2019, 15, 2447–2457, doi:10.3762/bjoc.15.237

• activation of the N-benzamidomethyltetrazole core followed by isoquinolone-ring formation to furnish 4a. We endeavored two catalytic systems based on ruthenium and rhodium, which in our laboratory have proven success in this type of cyclization [32][48]. First, the alkynylation protocol was attempted using

• the relatively cheap complex (p-cymene)ruthenium(II) chloride dimer, in the presence of copper(II) acetate as oxidant under conventional heating. Despite all effort put in this attempt, the isolated yields were in the range of 14–62%, with the highest yield achieved after 24 h of reaction using 10 mol

• % of catalyst (results not shown, see Supporting Information File 1). We next turned to rhodium catalysis, since despite the fact that rhodium-based catalysts are more expensive, they have proven to be very efficient using lower catalyst loadings compared to ruthenium [30][32][39][55]. Fortunately, the

Recent advances in transition-metal-catalyzed incorporation of fluorine-containing groups

• Xiaowei Li,
• Xiaolin Shi,
• Xiangqian Li and
• Dayong Shi

Beilstein J. Org. Chem. 2019, 15, 2213–2270, doi:10.3762/bjoc.15.218

• different catalysts, such as palladium, copper, silver, iron, nickel, ruthenium, cobalt, etc. Palladium catalysis Palladium is a member of the nickel triad in the periodic table, and palladium complexes exist in three oxidation states, Pd(0), Pd(II), and Pd(IV). Straightforward interconversion between

Click chemistry towards thermally reversible photochromic 4,5-bisthiazolyl-1,2,3-triazoles

• Chenxia Zhang,
• Kaori Morinaka,
• Mahmut Kose,
• Takashi Ubukata and
• Yasushi Yokoyama

Beilstein J. Org. Chem. 2019, 15, 2161–2169, doi:10.3762/bjoc.15.213

• electron-withdrawing cyano groups than when they are electron-donating methoxy groups. Keywords: aromatic stabilization energy; diarylethene; ruthenium(I) catalysed Huisgen cyclization; terarylene; thermally reversible photochromism; Introduction Diarylethenes are one of the most widely investigated

Attempted synthesis of a meta-metalated calix[4]arene

• Christopher D. Jurisch and
• Gareth E. Arnott

Beilstein J. Org. Chem. 2019, 15, 1996–2002, doi:10.3762/bjoc.15.195

• potential implications for asymmetric catalysis, due to the inherent chirality of the calix[4]arene, coupled with the point chirality from, for example, a tetrahedral ruthenium center. We therefore decided to apply the methods reported by Albrecht to a calix[4]arene system in order to prove this theory

• . Results and Discussion Model study An unreported model ruthenium metallocycle was first synthesized, based on the work published by Albrecht and co-workers, in order to gain a better understanding of the metallocycle synthetic challenges. To this end, known 1-bromo-4-propoxybenzene (1) underwent an

• , followed by metalation of the triazolium salt 4 with silver oxide, which was immediately transmetalated with [RuCl2(p-cymene)]2. In our hands, purification using Albrecht’s trituration method was unsuccessful, however, neutral alumina column chromatography produced the desired model ruthenium metallocycle

A review of the total syntheses of triptolide

• Xiang Zhang,
• Zaozao Xiao and
• Hongtao Xu

Beilstein J. Org. Chem. 2019, 15, 1984–1995, doi:10.3762/bjoc.15.194

• formal synthesis of triptolide and triptonide (Figure 2, route M) [48]. This synthesis highlights the use of Noyori’s ruthenium-catalyzed enantioselective transfer hydrogenation to introduce the chiral center; the indium(III)-catalyzed cationic polyene cyclization to construct the tricyclic A-, B- and C

N-(1-Phenylethyl)aziridine-2-carboxylate esters in the synthesis of biologically relevant compounds

• Iwona E. Głowacka,
• Aleksandra Trocha,
• Andrzej E. Wróblewski and
• Dorota G. Piotrowska

Beilstein J. Org. Chem. 2019, 15, 1722–1757, doi:10.3762/bjoc.15.168

• and next (R)-118 were formed. The aziridine ring opening in (2S,1'R/S,1''R)-28 gave the acetate (1R/S,2S,1'R)-106 which was transformed into the 1,3-oxazolidin-2-one (4S,5R/S,1'R)-121 a precursor to (R)-118. Catalytic ruthenium tetroxide oxidation of (R)-118 followed by hydrolysis gave ᴅ-phenylalanine

Recent advances on the transition-metal-catalyzed synthesis of imidazopyridines: an updated coverage

• Gagandeep Kour Reen,
• Ashok Kumar and
• Pratibha Sharma

Beilstein J. Org. Chem. 2019, 15, 1612–1704, doi:10.3762/bjoc.15.165

• alkenes and alkynes [74]. Rh(I)/Rh(II)/Rh(III) catalysts have been used in asymmetric syntheses of chiral heterocycles that have been effectively reviewed by Chen and Xu in 2017 [75]. The role of ruthenium in synthetic chemistry Over the past decade, Ru and its complexes were used as a catalyst in various

• organic processes and have attracted considerable interest in this regard. Ru has efficiently catalyzed C–H activation reactions for C–C bond formation, aza-Michael reactions and many more MCRs [27][76][77]. During the writing of this review, we came through the fact that ruthenium catalysts were mostly

Transient and intermediate carbocations in ruthenium tetroxide oxidation of saturated rings

• Manuel Pedrón,
• Laura Legnani,
• Maria-Assunta Chiacchio,
• Pierluigi Caramella,
• Tomás Tejero and
• Pedro Merino

Beilstein J. Org. Chem. 2019, 15, 1552–1562, doi:10.3762/bjoc.15.158

• A. Doria 6, 95125 Catania, Italy Dipartimento di Chimica, Università di Pavia, Via Taramelli, 12, 27100, Pavia, Italy Instituto de Síntesis Química y Catálisis Homogénea (ISQCH), Campus San Francisco, Universidad de Zaragoza-CSIC, 50009 Zaragoza, Spain 10.3762/bjoc.15.158 Abstract The ruthenium

• carbocation. In the case of pyrrolidines, the carbocation is completely stabilized as an energy minimum in the form of an iminium ion and the reaction takes place in two steps. Keywords: alkanes; carbocations; DFT; oxidations; ruthenium tetroxide; Introduction Ruthenium-catalyzed oxidations [1][2] and, in

• particular, those involving ruthenium tetroxide [3][4] occupy a privileged position among the modern oxidation methods due to their versatility regarding functional groups that can be oxidized and formed [5]. Alkane functionalization continues to be a current challenge in organic synthesis [6] and oxidation

Complexation of a guanidinium-modified calixarene with diverse dyes and investigation of the corresponding photophysical response

• Yu-Ying Wang,
• Yong Kong,
• Zhe Zheng,
• Wen-Chao Geng,
• Zi-Yi Zhao,
• Hongwei Sun and
• Dong-Sheng Guo

Beilstein J. Org. Chem. 2019, 15, 1394–1406, doi:10.3762/bjoc.15.139

• intramolecular charge-transfer dyes. Phosphated tetraphenylethylene was involved as the classical aggregation-induced emission dye. Sulfonated acedan representing one example of two-photon fluorescent probes, was also investigated. A ruthenium(II) complex with carboxylated bipyridyl ligands was included as a

• (EY), rose bengal (RB), tetraphenylporphine sulfonate (TPPS), sulfonated aluminum phthalocyanine (AlPcS4), 2-(p-toluidinyl)naphthalene-6-sulfonic acid (2,6-TNS), 1-anilinonaphthalene-8-sulfonic acid (1,8-ANS), phosphated tetraphenylethylene (P-TPE), sulfonated acedan (TPS), and a ruthenium(II) complex

• , higher spacial resolution and reduced photodamage of tissue [59]. The complexation of GC5A with the luminescent transition-metal complex Luminescent transition-metal complexes, especially those with ruthenium (Ru), are of great importance owing to their well-documented chemical stability, abundant

Hoveyda–Grubbs catalysts with an N→Ru coordinate bond in a six-membered ring. Synthesis of stable, industrially scalable, highly efficient ruthenium metathesis catalysts and 2-vinylbenzylamine ligands as their precursors

• Kirill B. Polyanskii,
• Kseniia A. Alekseeva,
• Pavel V. Raspertov,
• Pavel A. Kumandin,
• Eugeniya V. Nikitina,
• Atash V. Gurbanov and
• Fedor I. Zubkov

Beilstein J. Org. Chem. 2019, 15, 769–779, doi:10.3762/bjoc.15.73

• ; cross metathesis; Hoveyda–Grubbs catalyst; olefin metathesis; RCM; ring-closing metathesis; ring-opening cross metathesis; ROCM; ruthenium metathesis catalyst; styrene; 2-vinylbenzylamine; Introduction Ruthenium-catalysed olefin metathesis reactions have been playing an important role in various fields

• , ring-opening metathesis polymerization – ROMP and acyclic diene metathesis – ADMET. This motivates the investigations into the development of new, efficient, stable, and highly selective catalytic systems based on ruthenium complexes. However, in reality, a limited set of commercially available

• catalysts is used for the whole range of metathesis reactions most probably due to economical reasons. For example, in 2018, Merck offered more than 20 ruthenium metathesis catalysts. The most popular of them are shown in Figure 1. The framework of these catalysts consists of two main parts that surround

Synthesis of the aglycon of scorzodihydrostilbenes B and D

• Katja Weimann and
• Manfred Braun

Beilstein J. Org. Chem. 2019, 15, 610–616, doi:10.3762/bjoc.15.56

• Katja Weimann Manfred Braun Institute of Organic and Macromolecular Chemistry, Heinrich-Heine-University Düsseldorf, Universitätsstr. 1, D-40225 Düsseldorf, Germany 10.3762/bjoc.15.56 Abstract Benzyl- and methyl-protected 2,4-dihydroxyacetophenones are added under ruthenium catalysis to 4-methoxy

• , among them the aglycon of scorzodihydrostilbenes B and D. Keywords: C–H activation; hydroarylation; phenols; regioselectivity; ruthenium; Introduction Among phytochemicals with strong allelopathic effects, various natural products are found that feature the structural motif of dihydrostilbene with

• this article, we describe a synthetic approach that takes advantage of a regioselective, ruthenium-catalyzed C–H activation [6] and makes accessible not only the skeleton of dihydrostilbenes with multiple phenolic ether functionality but also the aglycon of scorzodihydrostilbenes B and D (2 and 4, R1

A chemoenzymatic synthesis of ceramide trafficking inhibitor HPA-12

• Seema V. Kanojia,
• Sucheta Chatterjee,
• Subrata Chattopadhyay and
• Dibakar Goswami

Beilstein J. Org. Chem. 2019, 15, 490–496, doi:10.3762/bjoc.15.42

• reaction [20], tandem approach from (S)-Wynberg lactone [21], chiral ruthenium-catalyzed N-demethylative rearrangement of 1,2-isoxazolidines [22], gold(I)-catalyzed cyclization of a propargylic N-hydroxylamine [23], from β-sulfinamido ketones derived from chiral sulfinimines [24], and a Kornblum–DeLaMare

Aqueous olefin metathesis: recent developments and applications

• Valerio Sabatino and
• Thomas R. Ward

Beilstein J. Org. Chem. 2019, 15, 445–468, doi:10.3762/bjoc.15.39

• exploit biocompatible conditions. This review focuses on the progress made in aqueous olefin metatheses and their applications in chemical biology. Keywords: aqueous catalysis; artificial metalloenzymes; chemical biology; green chemistry; olefin metathesis; ruthenium catalysts; stapled peptides

• ][18][19][20]. Ruthenium-based catalysts are among the most tolerant and stable metathesis catalysts and are widely employed for metatheses in aqueous media [21][22]. There is a growing interest in performing metathesis reactions in water as a greener alternative to chlorinated or aromatic solvents [23

• decarbonylation of the ruthenium hydride 16. In 2015, Cazin and co-workers showed that the detrimental effect of H2O also occurs with the more innovative catalysts Caz-I, Ind-II and HG-II (Table 1) [32]. The authors performed the RCM of the challenging substrate 17 in toluene at 110 °C, reporting excellent yields

Application of olefin metathesis in the synthesis of functionalized polyhedral oligomeric silsesquioxanes (POSS) and POSS-containing polymeric materials

• Patrycja Żak and
• Cezary Pietraszuk

Beilstein J. Org. Chem. 2019, 15, 310–332, doi:10.3762/bjoc.15.28

• the properties and applications of the resulting materials. Vinylsilanes show a specific reactivity towards alkylidene ruthenium complexes because of a strong effect of the silyl group on the properties of the double bond. In general, the substituents at the silicon atom determine the regioselectivity

• of the process to a certain degree. The reactivity of vinylsilanes with different substituents at silicon towards alkylidene ruthenium complexes is illustrated in Scheme 1 [7]. According to Scheme 1a, as a result of the reaction of trialkoxy-, tris(trimethylsiloxy)-, trichloro- or dichloromethyl

• undergoes fast decomposition as a result of β-transfer of the silyl group in the appropriate β-(silyl)rutenacyclobutane complex to ruthenium followed by reductive elimination of the corresponding propene derivative (Scheme 1c). The transformation resulted in complexes that do not contain a carbene ligand

Synthesis of 1,2-divinylcyclopropanes by metal-catalyzed cyclopropanation of 1,3-dienes with cyclopropenes as vinyl carbene precursors

• Jesús González,
• Alba de la Fuente,
• María J. González,
• Laura Díez de Tejada,
• Luis A. López and
• Rubén Vicente

Beilstein J. Org. Chem. 2019, 15, 285–290, doi:10.3762/bjoc.15.25

• importantly, with complete endo (syn) selectivity. The use of gold, platinum or ruthenium catalysts showed poorer results with respect to reaction yield and endo/exo (syn/anti) selectivity, as indicated in Scheme 2. Considering these results, the scope of the reaction with unbiased 1,3-dienes was next