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

• having a triisopropoxy(propyl)silyl ((-CH2)3Si(OiPr)3) substituent on the imidazole ring through in situ transmetallation. One of these complexes, 78a, was successfully anchored on mesoporous silica MCM-41 to afford a new heterogeneous catalyst (Scheme 27). Both compounds were subsequently used as

• . Unexpectedly, no reaction occurred when complex 78 anchored on mesoporous silica 78a-MCM-41 was used as heterogeneous catalyst. 2.2 Conjugate addition The conjugate addition is a reaction in which a nucleophile attacks at the β-position of an activated C=C moiety to give an addition product (Scheme 39). As

Light-responsive rotaxane-based materials: inducing motion in the solid state

• Adrian Saura-Sanmartin

Beilstein J. Org. Chem. 2023, 19, 873–880, doi:10.3762/bjoc.19.64

• is the functionalization of mesoporous silica nanoparticles with light-responsive rotaxane-based molecular shuttles to control the uptake and release of target molecules [31][32][33][34]. This perspective is focused on recent examples of light-responsive rotaxane-based solid-state materials in which

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

• catalytic activity of selenium mesoporous molecular sieves (SeMCM-41) in the oxidation of 16 (Table 1, entry 10). The approach was performed using H2O2 as oxidant in acetic acid over SeMCM-41 (Si/Se = 30) at 100 °C [56]. In this case, a conversion of 99% was achieved and menadione (10) was obtained with 68

• generation of waste or the use of environmentally friendly conditions, and they also allow recycling catalysts without losing efficiency [67][68][70]. Kholdeeva and co-workers reported the use of 30% aqueous H2O2 as oxidant and hydrothermally stable mesoporous mesophase titanium silicates (Ti-MMM-2) as

• catalyst group, producing 10 in 78% yield at 100% substrate conversion (Table 2, entry 2) [65]. During the studies it was observed that crucial factors affected the product yield, such as substrate concentration, H2O2/substrate molar ratio, solvent nature, reaction temperature, and mesoporous size [65

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

• that the oxidative addition of the nickel(0) species 10-VII to aryl bromide 3 and subsequent steps to produce nickel(III) intermediate 10-IX could not be ruled out. The König group discovered that the arylation of α-amino C(sp3)–H bonds could be realized with aryl halides using mesoporous graphitic

Constrained thermoresponsive polymers – new insights into fundamentals and applications

• Patricia Flemming,
• Alexander S. Münch,
• Andreas Fery and
• Petra Uhlmann

Beilstein J. Org. Chem. 2021, 17, 2123–2163, doi:10.3762/bjoc.17.138

A comprehensive review of flow chemistry techniques tailored to the flavours and fragrances industries

• Guido Gambacorta,
• James S. Sharley and
• Ian R. Baxendale

Beilstein J. Org. Chem. 2021, 17, 1181–1312, doi:10.3762/bjoc.17.90

• reagent incorporation into a mixture of monomers which are co-polymerised to create a network of micro- and mesoporous channels that fill the entirety of the tube/column. In a coated wall reactor, the reagent is immobilised onto the inner surface of the reactor. Finally, packed bed reactor columns are

• comparable outcomes. A similar system was later described by Asefa et al. The authors packed a jacketed glass capillary microreactor with an amine-functionalised mesoporous silica (AP-T) pressed into small pellets (Scheme 22) [134]. The apparatus enabled the preparation of p-hydroxy-β-nitrostyrene (103) in

Microwave-assisted multicomponent reactions in heterocyclic chemistry and mechanistic aspects

• Shivani Gulati,
• Stephy Elza John and
• Nagula Shankaraiah

Beilstein J. Org. Chem. 2021, 17, 819–865, doi:10.3762/bjoc.17.71

A new and efficient methodology for olefin epoxidation catalyzed by supported cobalt nanoparticles

• Lucía Rossi-Fernández,
• Viviana Dorn and
• Gabriel Radivoy

Beilstein J. Org. Chem. 2021, 17, 519–526, doi:10.3762/bjoc.17.46

• heterogeneous [33][34][35][36][37] Co-based catalysts have been applied to the epoxidation of alkenes, however, most of the reported methods lead to unsatisfactory yield, low selectivity, or limited substrate scope. Suib et al. [38] reported on the synthesis of mesoporous Co3O4 for the catalytic epoxidation of

• a variety of alkenes as an interesting heterogeneous system. This cobalt oxide mesoporous nanomaterial showed good activity and selectivity to the epoxide product and could be recovered and reused, but the multistep (not straightforward) synthesis of the catalyst and the use of DMF as the solvent

An atom-economical addition of methyl azaarenes with aromatic aldehydes via benzylic C(sp³)–H bond functionalization under solvent- and catalyst-free conditions

• Divya Rohini Yennamaneni,
• Vasu Amrutham,
• Krishna Sai Gajula,
• Rammurthy Banothu,
• Murali Boosa and
• Narender Nama

Beilstein J. Org. Chem. 2020, 16, 3093–3103, doi:10.3762/bjoc.16.259

• , the desired compound 3a was observed in traces. We thought that the catalyst pore size may be an obstruction to a higher yield and used a mesoporous material, MCM-41, as a catalyst, which slightly improved the yield (Table 1, entry 2). At the same time, increasing the temperature to 130 °C enhanced

Activation of pentafluoropropane isomers at a nanoscopic aluminum chlorofluoride: hydrodefluorination versus dehydrofluorination

• Maëva-Charlotte Kervarec,
• Thomas Braun,
• Mike Ahrens and
• Erhard Kemnitz

Beilstein J. Org. Chem. 2020, 16, 2623–2635, doi:10.3762/bjoc.16.213

• -tetrafluoropropene (HFO-1234ze) using mesoporous nanoscopic aluminum fluoride-based catalysts [19]. The catalysts were prepared via a sol–gel process in the presence of polyols, allowing for the evolution of a large surface area and improved acidic properties when compared to fluorinated Cr2O3 or traditional β-AlF3

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

• . studied a combination of a Ru/C catalyst with mesoporous niobium phosphate and Ru support over mesoporous niobium phosphate in the conversion of cellulose to isosorbide [28]. Different preparation methods of NbOPO4 were performed depending on the final pH (2, 7 and 10) of the solution at the end of the

• first run was observed. A sustainable method for the isosorbide production from cellulose is the use of a bifunctional catalyst (Scheme 7). A series of Ru catalysts on acid support were prepared by the adsorption of colloidal Ru nanoparticles on mesoporous and bulk niobium phosphate, mesoporous and bulk

• niobium oxide hydrate, phosphoric acid-treated mesoporous and bulk niobium oxide hydrate [30]. These catalysts were compared to Ru@HZMS5, Ru@NaY, Ru@γ-Al2O3 solids. Cellulose was converted over all niobia-based catalysts with 25–43% yield of isosorbide starting from 0.6 g cellulose using 0.06 g catalyst

Heterogeneous photocatalysis in flow chemical reactors

• Christopher G. Thomson,
• Ai-Lan Lee and
• Filipe Vilela

Beilstein J. Org. Chem. 2020, 16, 1495–1549, doi:10.3762/bjoc.16.125

• carriers) occurs over 200 femtoseconds. The resulting polarons migrate by “hopping” between the sheets until they eventually recombine over a period of approximately 10−13–10−6 s (Figure 10) [107]. Mesoporous graphitic carbon nitride (mpg-C3N4) has recently been reported by Antonietti, König, and co

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

• starting materials. The thermal decomposition behavior of the precursors, and thus the resulting morphology of the carbon materials is influenced by the propiolate cations [80]. Spherical carbons The preparation of spherical mesoporous carbon particles as catalyst support with high surface areas

• ) activation methods for the modification of the porosity of anthracite-based activated carbons. The final pore size distribution (mainly microporous or mainly mesoporous) depends on the choice of the activation agent, the treatment time and temperature and the initial textural properties of anthracite as

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

• , with a high surface area, could be employed as electronic devices, thermal or electronic insulators, catalysts, and humidity sensors [24]. Moreover, mesoporous silica nanomaterials benefit from unique properties, including a large surface area, uniform pore size and distribution, high chemical/thermal

• triazole products, excellent reusability, short reaction times, and good to high yields. Further, Dufauda et al. reported a copper(II)–phenanthroline complex supported on the SBA-15 architecture, Cu(II)phen@SBA-15 (58) [31]. The preparation is outlined in Scheme 9: Initially, phen-functionalized mesoporous

• types of carbon nanomaterials, including a) zero-dimensional nanoparticles (NPs), b) one-dimensional nanotubes, c) two-dimensional graphene sheets, and d) three-dimensional mesoporous carbon have been reported in the literature [63]. In this regard, various functionalized carbon nanomaterials were

Functional panchromatic BODIPY dyes with near-infrared absorption: design, synthesis, characterization and use in dye-sensitized solar cells

• Quentin Huaulmé,
• Cyril Aumaitre,
• Outi Vilhelmiina Kontkanen,
• David Beljonne,
• Alexandra Sutter,
• Gilles Ulrich,
• Renaud Demadrille and
• Nicolas Leclerc

Beilstein J. Org. Chem. 2019, 15, 1758–1768, doi:10.3762/bjoc.15.169

• were investigated using UV–vis spectroscopy, and we show that they can absorb light up to 900 nm in solution and 1000 nm in solid state, after grafting on anatase-TiO2 mesoporous films. The cyclic voltammetry (CV) measurements indicate that the compounds have HOMO and LUMO energy levels suitable for an

• solution located at 771 nm and 768 nm, respectively, with an absorption edge close to 900 nm. The absorption in the NIR region is a peculiar property that is of course a considerable advantage for solar cell applications. With the aim of investigating the behavior of those dyes once adsorbed on mesoporous

• TiO2, sensitization has been performed on 2 µm thick TiO2 mesoporous layer (see Figure 5b and c). To prevent dye aggregation on the surface of the semi-conducting oxide, and to mimic the real conditions of use in solar cells, chenodeoxycholic acid (CDCA) was employed as co-sensitizer and hence added to

Multicomponent reactions (MCRs): a useful access to the synthesis of benzo-fused γ-lactams

• Edorta Martínez de Marigorta,
• Jesús M. de Los Santos,
• Ana M. Ochoa de Retana,
• Javier Vicario and
• Francisco Palacios

Beilstein J. Org. Chem. 2019, 15, 1065–1085, doi:10.3762/bjoc.15.104

• -component reaction, to afford isoindolinones 53 substituted with nitrile or carboxamide groups (Scheme 15, method A) [93]. Trimethylsilylcyanide (52), and benzyl-, alkyl- and allylamines 2 were reacted with 2-formylbenzoic acid (33) in the presence of OSU-6, a mesoporous silica performing as a green Lewis

MoO₃ on zeolites MCM-22, MCM-56 and 2D-MFI as catalysts for 1-octene metathesis

• Hynek Balcar,
• Martin Kubů,
• Naděžda Žilková and
• Mariya Shamzhy

Beilstein J. Org. Chem. 2018, 14, 2931–2939, doi:10.3762/bjoc.14.272

• carbenes as real catalytically active species has been suggested [6][7]. The replacement of ordinary silicas for mesoporous molecular sieves SBA-15 or MCM-41 increased the catalyst activity substantially, which allowed performing the metathesis of long chain olefins under mild reaction conditions [8][9][10

• ) where MoO3 signals were clearly visible, probably as a result of lower external surface area. Contrary to the all-siliceous mesoporous sieves (like SBA-15) which are neutral, zeolites are acidic and their acidity (both Brønsted and Lewis-type) plays an important role for catalysis. The acid site

• good accessibility of active species by substrate molecules. The most active 6MoO3/MCM-22(28) exhibited a significantly higher activity than that of a similar catalyst supported on siliceous mesoporous molecular sieve SBA-15. Due to the catalyst acidity accompanying reactions occurred: (i) 1-octene

An overview on recent advances in the synthesis of sulfonated organic materials, sulfonated silica materials, and sulfonated carbon materials and their catalytic applications in chemical processes

• Hashem Sharghi,
• Pezhman Shiri and
• Mahdi Aberi

Beilstein J. Org. Chem. 2018, 14, 2745–2770, doi:10.3762/bjoc.14.253

• . carried out the synthesis of 2H-indazolo[2,1-b]phthalazinetrione derivatives 55 and triazolo[1,2-a]indazoletrione derivatives 81 using solvent-free reactions between aldehydes 7, dimedone (20), and phthalazine (54) or N-phenylurazoles (80) at 80 °C in the presence of catalytic amount of a mesoporous SBA

• sulfonated mesoporous silica materials is that they are poisoned with water. To increase the hydrophobicity of them, the authors reported some solutions such as confining fluoroalkyl-chain alcohols (RFOH) inside them. A range of RFOH including trifluoroethanol (TFE), ethanol, hexafluoroisopropanol (HFIP) was

• -functionalized catalyst. The SBA-15-SO3H containing fluorinated alcohols had more catalytic activity [60]. In an initiative research, Doustkhah and Rostamnia developed a green catalytic system based on SBA-15 mesoporous silica with sulfamic acid content. This heterogeneous Brønsted solid acid was used as an

Tetrathiafulvalene – a redox-switchable building block to control motion in mechanically interlocked molecules

• Hendrik V. Schröder and
• Christoph A. Schalley

Beilstein J. Org. Chem. 2018, 14, 2163–2185, doi:10.3762/bjoc.14.190

• MOF NU-1000 consists of Zr6 nodes which are bridged by 1,3,6,8-tetrakis(p-carboxyphenyl)pyrene ligands [109]. Four hydroxy groups of each metal cluster are pointing into the mesoporous channels of the MOF and can be post-functionalized. Similar to a previous report about rotaxanes implemented into a

Graphitic carbon nitride prepared from urea as a photocatalyst for visible-light carbon dioxide reduction with the aid of a mononuclear ruthenium(II) complex

• Kazuhiko Maeda,
• Daehyeon An,
• Ryo Kuriki,
• Daling Lu and
• Osamu Ishitani

Beilstein J. Org. Chem. 2018, 14, 1806–1812, doi:10.3762/bjoc.14.153

• reduction systems using g-C3N4-based materials, in combination with functional metal complexes [8][9][10][11][12][13][14][15][16]. For example, mesoporous g-C3N4 (mpg-C3N4) modified with a mononuclear Ru(II) complex, such as trans-(Cl)-Ru{(PO3H2)2bpy(CO)2Cl2} (bpy: 2,2’-bipyridine), abbreviated as RuP, is

CF₃SO₂X (X = Na, Cl) as reagents for trifluoromethylation, trifluoromethylsulfenyl-, -sulfinyl- and -sulfonylation and chlorination. Part 2: Use of CF₃SO₂Cl

• Hélène Chachignon,
• Hélène Guyon and
• Dominique Cahard

Beilstein J. Org. Chem. 2017, 13, 2800–2818, doi:10.3762/bjoc.13.273

• -workers thereafter reported that the trifluoromethylation of (hetero)arenes could also be performed under heterogeneous catalysis [33]. To this aim, the Ru- or Ir-based catalysts were replaced with a mesoporous graphitic carbon nitride polymer (mpg-CN), which offers the advantage of being cheap, metal

Novel approach to hydroxy-group-containing porous organic polymers from bisphenol A

• Tao Wang,
• Yan-Chao Zhao,
• Li-Min Zhang,
• Yi Cui,
• Chang-Shan Zhang and
• Bao-Hang Han

Beilstein J. Org. Chem. 2017, 13, 2131–2137, doi:10.3762/bjoc.13.211

• % (Figure 4d), which is higher than that of the reported mesoporous polymeric organic frameworks (mesoPOF)s [23]. PPOP-2 with the largest BET surface area and micropore volume shows the highest methane uptake. However, PPOP-3 possesses a smaller methane storage capacity than PPOP-1 that is known for its

New bio-nanocomposites based on iron oxides and polysaccharides applied to oxidation and alkylation reactions

• Daily Rodríguez-Padrón,
• Alina M. Balu,
• Antonio A. Romero and
• Rafael Luque

Beilstein J. Org. Chem. 2017, 13, 1982–1993, doi:10.3762/bjoc.13.194

• , Figures S2–S4 for the XPS spectra). Nitrogen physisorption The textural properties of the materials have been studied with N2 absorption–desorption isotherms analysis. The TiO2-Fe2O3-PS4 nanomaterial presents a mesoporous structure with a pore size of 20 nm and a surface area of 58 m2/g. However, in the

• other two catalysts, a particular macroporosity was found at p/p0 > 0.98 (isotherms of type III), which are clearly dissimilar to those of conventionally ordered mesoporous materials [53] having a sharp increase in p/p0 from 0.85 to 0.90 (see Supporting Information File 1, Figure S5 for all adsorption

Mechanochemical synthesis of graphene oxide-supported transition metal catalysts for the oxidation of isoeugenol to vanillin

• Ana Franco,
• Sudipta De,
• Alina M. Balu,
• Araceli Garcia and
• Rafael Luque

Beilstein J. Org. Chem. 2017, 13, 1439–1445, doi:10.3762/bjoc.13.141

• were characterized by using several techniques including BET, SEM, TEM, XRD, and IR spectroscopy. N2 adsorption/desorption isotherms of the reduced graphene sample (Figure 1a) can be classified as type IV corresponding to the mesoporous materials. The RGO sample showed a BET surface area of 103 m2 g−1

• with a pore diameter of 39 nm and pore volume of 0.74 cm3 g−1 (Table 1). After the ball milling with metal precursors, the mesoporous structure of RGO was found to be partially collapsed as observed from BET isotherms in Figure 1b and c. BET surface areas of metal supported RGO materials consequently

• mesoporous nature of the RGO can be easily observed from SEM images (Figure 2a and b), whereas metal-supported RGO materials show a smooth surface with decreased crystallinity. TEM images of RGO materials with different thickness show a sheet like morphology with different transparencies (Figure 3). Dark

Mechanochemistry-assisted synthesis of hierarchical porous carbons applied as supercapacitors

• Desirée Leistenschneider,
• Nicolas Jäckel,
• Felix Hippauf,
• Volker Presser and
• Lars Borchardt

Beilstein J. Org. Chem. 2017, 13, 1332–1341, doi:10.3762/bjoc.13.130

• . Keywords: electrochemical energy storage; mesoporous; microporous; solvent-free; supercapacitor; templated carbon; Introduction Porous carbons are key components in many energy and environmentally-relevant applications, such as catalysis [1], gas storage and separation [2][3], and electrochemical energy

• for the synthesis of uniform metal oxide nanoparticles to synthesize a titanium(IV) citrate-based polymer [44][45]. The Pechini method is applicable to synthesize templated mesoporous carbons [46][47][48][49], but has never been utilized for a solvent-free and rapid process based on mechanochemistry

• comparable to other known Kroll carbons [52] and non-doped mesoporous carbons [57]. At a high sweep rate of 500 mV s−1, the shape of the CV, recorded in the organic electrolyte (Figure 7A) remains nearly rectangular, which indicated a high power handling ability. The ion mobility of ionic liquids is lower