A novel and robust heterogeneous Cu catalyst using modified lignosulfonate as support for the synthesis of nitrogen-containing heterocycles

• Bingbing Lai,
• Meng Ye,
• Ping Liu,
• Minghao Li,
• Rongxian Bai and
• Yanlong Gu

Beilstein J. Org. Chem. 2020, 16, 2888–2902, doi:10.3762/bjoc.16.238

• a robust supporting material to immobilize a copper species. The so-obtained catalyst was characterized by many physicochemical methods including FTIR, EA, FSEM, FTEM, XPS, and TG. This catalyst exhibited excellent catalytic activity in the synthesis of nitrogen-containing heterocycles such as

• spectra were further recorded, and the results confirmed the presence of Cu+ at ≈570 eV, while Cu0 at 565.6 eV [29][30][31], meaning that Cu2+ species were partially reduced during the course of immobilization. Catalytic activity of the catalysts With the catalysts in hand, we investigated their catalytic

• were formed (Table 1, entry 1). After screening different kind of solvents (Table 1, entries 2–8) at 60 °C, EtOH was found to be the best one, and the target product 4a was obtained in 86% yield (Table 1, entry 8). The referential catalysts LS-FM-Cu and Resin-Cu showed inferior catalytic activity for

Using multiple self-sorting for switching functions in discrete multicomponent systems

• Amit Ghosh and
• Michael Schmittel

Beilstein J. Org. Chem. 2020, 16, 2831–2853, doi:10.3762/bjoc.16.233

• innovative catch–release system with multiple functions combined the ON/OFF-adjustment of silver(I) catalysis and fluorescence monitoring [59]. Actually, the ratiometric luminescence response allowed the exact monitoring of the catalytic activity. In the initial incomplete self-sorting (state SelfSORT-I

• finding suggested that the catalytic activity in SelfSORT-II was reduced to roughly half of the initial activity in SelfSORT-I. Finally, the addition of two equiv of copper(I) ions generated SelfSORT-III where no additional product was afforded, indicating an OFF state of the catalytic machinery. To

• catalytic activity. In sum, this study demonstrated partial and full release/binding of the organocatalyst 75 during the walking of the biped. Rather recently, the Schmittel group described a precise intermolecular communication system, in which multiple self-sorting steps set up a catalytic AND gate

Palladium nanoparticles supported on chitin-based nanomaterials as heterogeneous catalysts for the Heck coupling reaction

• Tony Jin,
• Malickah Hicks,
• Davis Kurdyla,
• Sabahudin Hrapovic,
• Edmond Lam and
• Audrey Moores

Beilstein J. Org. Chem. 2020, 16, 2477–2483, doi:10.3762/bjoc.16.201

• deposit Pd NPs directly onto both ChNCs and ChsNCs, and the as-made heterogeneous catalysts were tested with the Heck coupling reaction as a model for catalytic activity. Findings The fabrication of ChNC and ChsNCs was conducted using a procedure previously reported by our group (Lam) (see Supporting

• system has higher catalytic activity in more benign conditions, with the Pd NP on SiO2 system yielding 92% stilbene product at 110 °C and using dimethylformamide as the solvent [23]. Other examples using carbon-based supports such as carbon spheres [24] and graphene oxide [25] also have formidable yields

Hierarchically assembled helicates as reaction platform – from stoichiometric Diels–Alder reactions to enamine catalysis

• David Van Craen,
• Jenny Begall,
• Johannes Großkurth,
• Leonard Himmel,
• Oliver Linnenberg,
• Elisabeth Isaak and
• Markus Albrecht

Beilstein J. Org. Chem. 2020, 16, 2338–2345, doi:10.3762/bjoc.16.195

• residues were introduced instead of the diene ligands. Again helicates with a statistical distribution of chiral ligands and of the new amine ligands in the complex were investigated as catalysts. The ligands with potential catalytic activity were synthesized in a three-step approach (Scheme 4). Initially

• equivalent of 13-H2 and 5 equivalents of 2-H2, 4-H2, and 5-H2. The catalytic activity of the amine ligands was tested first by using the uncoordinated ligand 13a-H2 substituted with a N-methylethylamine moiety. The reaction was performed in DMSO-d6 due to solubility limitations of the ligand. Fast and easy

• the supposed reason for this observation. Thus, the amine ligand 13b-H2 seemed to be an appropriate component to make helicates from ligand mixtures which possess catalytic activity. Exchange of the chiral ligand 2 by other chiral ones resulted in the corresponding complexes Li4[(13b)1(4)5Ti2] and Li4

Synthetic approaches to bowl-shaped π-conjugated sumanene and its congeners

• Shakeel Alvi and
• Rashid Ali

Beilstein J. Org. Chem. 2020, 16, 2212–2259, doi:10.3762/bjoc.16.186

• colorless crystals of 128. Along similar lines the crystals of 127 were achieved by following the same procedure. On the other hand, the groups of Amaya and Hirao have reported the synthesis of sumanenyl mono- and trihafnocene complexes 129 and 130, respectively, along with the catalytic activity of 129 for

• subjected 2 with an excess of t-BuLi and then quenched it with Cp*HfCl3 as displayed in Scheme 34. Furthermore, they revealed for the first time the catalytic activity of sumanene metallocene for the hydroethylation reaction of unactivated allylbenzene by treating it with AlEt3 at room temperature to

Azo-dimethylaminopyridine-functionalized Ni(II)-porphyrin as a photoswitchable nucleophilic catalyst

• Jannis Ludwig,
• Julian Helberg,
• Hendrik Zipse and
• Rainer Herges

Beilstein J. Org. Chem. 2020, 16, 2119–2126, doi:10.3762/bjoc.16.179

• switch the catalytic activity of the dimethylaminopyridine (DMAP) unit. DMAP is a known catalyst in the nitroaldol (Henry) reaction. Upon coordination to the Ni2+ ion, the basicity of the pyridine lone pair is attenuated and hence the catalytic activity is reduced. Decoordination restores the catalytic

• -epoxypropane to propylene carbonate using an aluminum porphyrin and a photoresponsive ligand. The catalytic activity of the metal porphyrin depended on the axial coordination of an azostilbene and coordination of the latter ligand was controlled by photoisomerization of the stilbene unit [9]. Hecht et al

• thermal relaxation of the coordinated cis state is insignificant for our catalytic studies. Experiments using porphyrin 1 as a catalyst The Henry reaction (Scheme 2) was chosen as a model reaction to investigate the catalytic activity of porphyrin 1 in the two different switching states because the rate

Efficient [(NHC)Au(NTf₂)]-catalyzed hydrohydrazidation of terminal and internal alkynes

• Maximillian Heidrich and
• Herbert Plenio

Beilstein J. Org. Chem. 2020, 16, 2080–2086, doi:10.3762/bjoc.16.175

• in hydrohydrazidation reactions than the previously reported [(Ph3P)Au(NTf2)] [42]. Solvent screening: Among the solvents tested in the previous study by Rassadin, Kukushkin et al., chlorobenzene was found to be the best solvent concerning the catalytic activity [42]. However, according to the CHEM21

Synergy between supported ionic liquid-like phases and immobilized palladium N-heterocyclic carbene–phosphine complexes for the Negishi reaction under flow conditions

• Edgar Peris,
• Raúl Porcar,
• María Macia,
• Jesús Alcázar,
• Eduardo García-Verdugo and
• Santiago V. Luis

Beilstein J. Org. Chem. 2020, 16, 1924–1935, doi:10.3762/bjoc.16.159

• PdII. In this way, a “cocktail” of catalytic species, including molecular complexes, clusters and nanoparticles may be responsible for the catalytic activity [15]. In a continuous system, this can be accompanied by a significant leaching of the catalytic metal. In order to avoid a loss of activity by

• kinetic plots for this model reaction are represented in Figure 1. The NHC–Pd catalyst 4a showed a rather reduced activity (less than 10% after two hours), while the catalyst bearing isopropyl moieties at the aromatic ring (4b) displayed a significant increase in the catalytic activity, reaching 67% yield

• enhanced precatalyst preparation, stabilization and initiation, PEPPSI) [23][24]. In addition to pyridine ligands, other compounds with coordinating atoms such as C, N or P have been reported to tune the catalytic activity of the NHC–Pd complexes [25][26][27][28]. Thus, a ligand containing P as the

Natural dolomitic limestone-catalyzed synthesis of benzimidazoles, dihydropyrimidinones, and highly substituted pyridines under ultrasound irradiation

• Kumar Godugu,
• Venkata Divya Sri Yadala,
• Mohammad Khaja Mohinuddin Pinjari,
• Trivikram Reddy Gundala,
• Lakshmi Reddy Sanapareddy and
• Chinna Gangi Reddy Nallagondu

Beilstein J. Org. Chem. 2020, 16, 1881–1900, doi:10.3762/bjoc.16.156

• , the elemental composition of the NDL catalyst was determined by EDAX analysis (Figure 6). The catalytic activity of the NDL for the synthesis of the 1,2-disubstituted benzimidazoles 3, the dihydropyrimidinones/-thiones 7, and the 2-amino-4-(hetero)aryl-3,5-dicarbonitrile-6-sulfanylpyridines 11 was

• investigated, along with other, commercially available catalysts. NDL-catalyzed synthesis of 1,2-disubtituted benzimidazoles 3 To check the catalytic activity of the NDL, initially, o-phenylenediamine (1) and benzaldehyde (2a) were chosen as model substrates to optimize the reaction conditions for the

• by comparison of the melting point and spectroscopic data with those reported. NDL-catalyzed synthesis of dihydropyrimidinones/-thiones 7 The results encouraged us to further investigate the catalytic activity of the NDL in the Biginelli reaction. To check the feasibility, a control experiment was

One-pot synthesis of isosorbide from cellulose or lignocellulosic biomass: a challenge?

• Isaline Bonnin,
• Raphaël Mereau,
• Thierry Tassaing and
• Karine De Oliveira Vigier

Beilstein J. Org. Chem. 2020, 16, 1713–1721, doi:10.3762/bjoc.16.143

• increased production of insoluble byproducts. The productivity of isosorbide can reach 40.2 g·L−1·h−1with a purity of 73%. The recycling of the metal-supported catalyst (Ru/C) was studied and a high catalytic activity decrease was observed after the first run, showing that the catalyst was not recyclable

Activated carbon as catalyst support: precursors, preparation, modification and characterization

• Melanie Iwanow,
• Tobias Gärtner,
• Volker Sieber and
• Burkhard König

Beilstein J. Org. Chem. 2020, 16, 1188–1202, doi:10.3762/bjoc.16.104

A smart deoxyribozyme-based fluorescent sensor for in vitro detection of androgen receptor mRNA

• Ekaterina A. Bryushkova,
• Erik R. Gandalipov and
• Julia V. Nuzhina

Beilstein J. Org. Chem. 2020, 16, 1135–1141, doi:10.3762/bjoc.16.100

•  2D, lane 6). As follows from Figure 2D (lanes 6 and 7), the presence of malachite green dye did not affect the catalytic activity of SDFS. Selectivity of SDFS cleavage activity in relation to 60-AR_RNA was tested with two random RNA sequences (Supporting Information File 1, Table S2, 62-RNA and 46

The charge-assisted hydrogen-bonded organic framework (CAHOF) self-assembled from the conjugated acid of tetrakis(4-aminophenyl)methane and 2,6-naphthalenedisulfonate as a new class of recyclable Brønsted acid catalysts

• Svetlana A. Kuznetsova,
• Alexander S. Gak,
• Yulia V. Nelyubina,
• Vladimir A. Larionov,
• Han Li,
• Michael North,
• Vladimir P. Zhereb,
• Alexander F. Smol'yakov,
• Artem O. Dmitrienko,
• Michael G. Medvedev,
• Igor S. Gerasimov,
• Ashot S. Saghyan and
• Yuri N. Belokon

Beilstein J. Org. Chem. 2020, 16, 1124–1134, doi:10.3762/bjoc.16.99

• volume of 0.00093 cm3⋅g−1, a macropore volume of 0.00168 cm3⋅g−1, and a total pore volume of 0.00336 cm3⋅g−1. The porosimetry data could not be directly relevant to the catalytic activity of the composite as the framework as the porosimetry sample needed to be thoroughly degassed prior to the analysis

• styrene oxide (2) with methanol. Within 1 hour at room temperature, the alcohol 3 was obtained in a quantitative yield and as a single regioisomer (Table 1, run 2). The CAHOF F-1 was robust and retained the catalytic activity after being recovered from the reaction mixture five times (Table 1, run 3). In

Recent advances in Cu-catalyzed C(sp³)–Si and C(sp³)–B bond formation

• Balaram S. Takale,
• Ruchita R. Thakore,
• Elham Etemadi-Davan and
• Bruce H. Lipshutz

Beilstein J. Org. Chem. 2020, 16, 691–737, doi:10.3762/bjoc.16.67

• , provided an opportunity for recycling and reuse. This catalyst, therefore, was isolated using simple centrifugation and reused in a second reaction leading to no appreciable loss in catalytic activity en route to product 218. It was also utilized not only for unsaturated ketones but also to deliver the

• coordination of (t-Bu)3P to CuCl is far greater than that with the diboron species, which results in an enhancement of the catalytic activity (Scheme 65) [128]. The one-pot borylation/protodeboronation of α,β-unsaturated ketones 405 in the presence of CuBr, B2pin2 and H2O as the hydrogen source was developed

Rhodium-catalyzed reductive carbonylation of aryl iodides to arylaldehydes with syngas

• Zhenghui Liu,
• Peng Wang,
• Zhenzhong Yan,
• Suqing Chen,
• Dongkun Yu,
• Xinhui Zhao and
• Tiancheng Mu

Beilstein J. Org. Chem. 2020, 16, 645–656, doi:10.3762/bjoc.16.61

• . In this work, we established a catalytic system composed of RhCl3·3H2O and PPh3, which allows the reductive carbonylation of aryl iodides using CO and H2 in the presence of Et3N as the base at 90 °C. In addition, the reported catalytic system demonstrates high catalytic activity affording the

Asymmetric synthesis of CF₂-functionalized aziridines by combined strong Brønsted acid catalysis

• Xing-Fa Tan,
• Fa-Guang Zhang and
• Jun-An Ma

Beilstein J. Org. Chem. 2020, 16, 638–644, doi:10.3762/bjoc.16.60

• examination on various arylboronic acids, solvent, temperature, and catalyst loadings resulted in no obvious improvement (Table 1, entries 9–15). Among them, the highest yield of 4a was observed (81%, Table 1, entry 12), albeit with slightly reduced ee value. This enhancement in catalytic activity could be

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

• ), respectively (Scheme 1). The catalysts were characterized by a series of analytical techniques. The solid-state 13C NMR of IPSi showed nine peaks at 10, 24, 43, 63, 121, 136, 148, 155, and 162 ppm, respectively. SEM analysis displayed an irregular shape for 1a and 1b. The catalytic activity of Cu(I)@IPSi (1a

• loss of catalytic activity. Using a multistep solid-phase procedure, Shantz et al. reported on SBA-15 functionalized with melamine-based dendrons (Scheme 3) [27]. The Cu and Cu/Au nanoparticles were then supported on this new composite to generate a nanocatalyst. The catalytic application of this

• ). The ICP analysis of 45 revealed a strong attachment of the copper species to the functionalized nanosilica. Furthermore, the composite 45 demonstrated good catalytic activity in five consecutive cycles. Recently, the synthesis and catalytic application of a copper(II)–2-imino-1,2-diphenylethan-1-ol

Copper-catalyzed enantioselective conjugate reduction of α,β-unsaturated esters with chiral phenol–carbene ligands

• Shohei Mimura,
• Sho Mizushima,
• Yohei Shimizu and
• Masaya Sawamura

Beilstein J. Org. Chem. 2020, 16, 537–543, doi:10.3762/bjoc.16.50

• plays crucial roles in both the catalytic activity and stereoselectivity [19][20][21]. Notably, these catalyst systems were also applicable for three-component coupling reactions using hydrosilanes as hydride reagents [17]. Based on this knowledge, we decided to investigate the effects of the phenol–NHC

Controlling alkyne reactivity by means of a copper-catalyzed radical reaction system for the synthesis of functionalized quaternary carbons

• Goki Hirata,
• Yu Yamane,
• Naoya Tsubaki,
• Reina Hara and
• Takashi Nishikata

Beilstein J. Org. Chem. 2020, 16, 502–508, doi:10.3762/bjoc.16.45

• produce 3g and 3h, respectively. An arylalkyne 1 possessing an electron-withdrawing group (ester) yielded 3i without affecting the reactivity of 2. Sulfur functional groups tend to decrease the catalytic activity of copper salts, but thienyl-substituted alkyne 1 reacted with 2a to produce 3j in 48% yield

Oligomeric ricinoleic acid preparation promoted by an efficient and recoverable Brønsted acidic ionic liquid

• Fei You,
• Xing He,
• Song Gao,
• Hong-Ru Li and
• Liang-Nian He

Beilstein J. Org. Chem. 2020, 16, 351–361, doi:10.3762/bjoc.16.34

• mentioning that the IL catalyst can be used at least for five cycles with high catalytic activity. As a result, the protocol based on the IL catalyst, i.e. [HSO3-BDBU]H2PO4 shows great potential in industrial production of oligomeric ricinoleic acid from ricinoleic acid. Keywords: bio-lubricant; ionic

• excellent catalytic activity for this intermolecular esterification reaction and Brønsted acidic ionic liquids have been successfully used as catalyst in organic syntheses [29][30][31], we designed a series of Brønsted acidic ionic liquids and applied them as catalysts for the preparation of oligomeric

• the catalytic activity of these functional ILs was evaluated with the acid value of the product as it is a convenient index to monitor the degree of oligomerization by reflecting the concentration of carboxy groups in the system, which has been cross verified by HPLC method [19][28]. The results

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

• ruthenium oxides/hydroxides on the surface. Ru nanocatalyst-catalysed C–H alkenylation of indoles After the synthesis of the RuNC, we explored the catalytic activity of the material in C–H alkenylation reactions of indole (1a). Initial optimisation of the conditions for the alkenylation reactions were

• results of the Hg poisoning test and, more importantly, the three-phase test, could allow us to reach the conclusion that the reactions were catalysed by a heterogeneous process. Role of the surface oxide and plausible mechanism One of the reasons for the high catalytic activity of the RuNC was the near

• target to synthesise zerovalent Ru nanoparticles. However, with respect to their catalytic ability, they are actually beneficial and responsible for the catalytic activity of the nanocatalyst towards the C–H activation reaction, since it has previously been shown that the presence of surface oxides on

Palladium-catalyzed Sonogashira coupling reactions in γ-valerolactone-based ionic liquids

• László Orha,
• József M. Tukacs,
• László Kollár and
• László T. Mika

Beilstein J. Org. Chem. 2019, 15, 2907–2913, doi:10.3762/bjoc.15.284

• and functionalized acetylenes under mild conditions. The reactions were performed by using 0.5 mol % catalyst loading and we pointed out that both copper and external base could be eliminated from the reaction mixture without any decrease in catalytic activity. The protocol was tested for a wide range

Self-assembled coordination thioether silver(I) macrocyclic complexes for homogeneous catalysis

• Zhen Cao,
• Aline Lacoudre,
• Cybille Rossy and
• Brigitte Bibal

Beilstein J. Org. Chem. 2019, 15, 2465–2472, doi:10.3762/bjoc.15.239

• of the two L2·(AgOTf)2 stereoisomers highlighted their different geometry. The catalytic activity of all silver(I) complexes was effective under homogeneous conditions in two tandem addition/cycloisomerization of alkynes using 0.5–1 mol % of catalytic loading. Keywords: coordination macrocycle

1,2,3-Triazolium macrocycles in supramolecular chemistry

• Mastaneh Safarnejad Shad,
• Pulikkal Veettil Santhini and
• Wim Dehaen

Beilstein J. Org. Chem. 2019, 15, 2142–2155, doi:10.3762/bjoc.15.211

• reaction with the highest enantioselectivity. The importance of the bifunctional system for the catalytic activity and enantioselectivity was demonstrated by performing a series of reactions with lower activity and selectivity, utilizing free-base porphyrin 16h with triazolium moieties and the two

Naphthalene diimides with improved solubility for visible light photoredox catalysis

• Barbara Reiß and
• Hans-Achim Wagenknecht

Beilstein J. Org. Chem. 2019, 15, 2043–2051, doi:10.3762/bjoc.15.201

• potential was estimated to be approximately +1.0 V (vs SCE) which is sufficient to photocatalyze typical organic reactions. The photoredox catalytic activity in the visible light range was tested by the α-alkylation of 1-octanal as benchmark reaction. Irradiations were performed with LEDs in the visible

• catalytic activity was representatively tested by the MacMillan benchmark reaction [53]. For this type of photoredox catalytic reaction, solubility of cNDIs in DMF is a crucial prerequisite. Results and Discussion Synthesis of cNDIs 2–6 and their solubility The commercially available precursor for all NDIs

• can be assigned to the electron-donating effect of the n-propylamino groups. The key values for the photoredox catalytic activity (vide infra) are the excited state potential for the reduction, E*red(2*/2•−) = +0.92 V, and for the oxidation E*ox(2•+/2*) = −0.99 V. According to the categories for