Green and sustainable approaches for the Friedel–Crafts reaction between aldehydes and indoles

• Periklis X. Kolagkis,
• Eirini M. Galathri and
• Christoforos G. Kokotos

Beilstein J. Org. Chem. 2024, 20, 379–426, doi:10.3762/bjoc.20.36

• were some issues that held back the universality of this protocol [125]. More recently, in 2022, Kaur et al. utilized CdS nanostructures which possess good Lewis acidity for the heterogeneous catalysis of various organic transformations including the synthesis of BIMs as shown by Chabukswar and his

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

• of purification cannot differentiate similar compounds if these contain the same functional groups. An advantage, however, is that this purification technique is easily coupled with heterogeneous catalysis. As such immobilized reagents and scavengers are more suited to catalytic processes than

Heterogeneous metallaphotoredox catalysis in a continuous-flow packed-bed reactor

• Wei-Hsin Hsu,
• Susanne Reischauer,
• Peter H. Seeberger,
• Bartholomäus Pieber and
• Dario Cambié

Beilstein J. Org. Chem. 2022, 18, 1123–1130, doi:10.3762/bjoc.18.115

• ; heterogeneous catalysis; metallaphotoredox catalysis; packed bed; photochemistry; Introduction The amount and impact of visible-light-mediated protocols in organic synthesis have increased dramatically since the late 2000s [1]. The main driving force of this phenomenon is the novel reactivity afforded by

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

• (Scheme 21). Dobrinescu and co-workers studied, besides acetylation reactions, the hydroacetylation of menadione for the synthesis of diacetylated menadiol derivatives through heterogeneous catalysis [121]. The first methodology involved the reduction of menadione (10) to menadiol (14), with sodium

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

• natural product synthesis, pigments and dyes. Different variety of α-amino carbonyls [2], α-amino acids [3] and 1,2-diamines were prepared from the nitriles using homogeneous and heterogeneous catalysis [4][5][6]. One of the astonishing aspects of nitriles is that it can be easily converted to amines

Catalyzed and uncatalyzed procedures for the syntheses of isomeric covalent multi-indolyl hetero non-metallides: an account

• Ranadeep Talukdar

Beilstein J. Org. Chem. 2021, 17, 2102–2122, doi:10.3762/bjoc.17.137

• with 5-iodoindole (182) in the presence of thiourea and a recyclable CuO nanoparticle catalyst (Scheme 26) [116]. This heterogeneous catalysis strategy bypasses the use of unpleasant aryl thiols, which are generally coupled with other aryl halides in the presence of transition-metal catalysts for

Correction: One-pot multicomponent green Hantzsch synthesis of 1,2-dihydropyridine derivatives with antiproliferative activity

• Giovanna Bosica,
• Kaylie Demanuele,
• José M. Padrón and
• Adrián Puerta

Beilstein J. Org. Chem. 2021, 17, 2026–2027, doi:10.3762/bjoc.17.130

• 10.3762/bjoc.17.130 Keywords: antiproliferative activity; 1,2-dihydropyridines; green Hantzsch synthesis; heterogeneous catalysis; one-pot multicomponent reaction; The authors noticed that the E-factor (E) was calculated using a wrong Equation 2 in the original publication: The correct Equation 2 should

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

• often a work-up procedure meaning that this approach is very accommodating of direct telescoping into further reaction steps and reactors. So far, heterogeneous catalysis of aldol reactions in flow has been mostly geared towards achieving transformations with high enantioselectivity, towards decreasing

• offer the advantage of high surface-to-volume ratio and scalability. These systems consist of nanoparticles embedded into a porous polymer matrix. In heterogeneous catalysis, a higher particle stability and good distribution of the catalyst leads to a reduction in pressure drop alongside a stronger

• optimised setup was shown to be reasonably stable for continuous runtimes of up to 100 hours. In the last few years, polyacrylonitrile fibres (PANF) along with other synthetic textiles have seized attention in heterogeneous catalysis as supports thanks to their incomparable mechanical properties and low

Recent advances in palladium-catalysed asymmetric 1,4–additions of arylboronic acids to conjugated enones and chromones

• Jan Bartáček,
• Jan Svoboda,
• Martin Kocúrik,
• Jaroslav Pochobradský,
• Alexander Čegan,
• Miloš Sedlák and
• Jiří Váňa

Beilstein J. Org. Chem. 2021, 17, 1048–1085, doi:10.3762/bjoc.17.84

• , continuous-flow reactions are currently a general challenge, especially for the pharmaceutical industry. The prerequisite for a successful continuous synthesis in the field of asymmetric addition reactions to enones is the mastery of recyclable heterogeneous catalysis. Very recently, we reported [57] the

Valorisation of plastic waste via metal-catalysed depolymerisation

• Francesca Liguori,
• Carmen Moreno-Marrodán and
• Pierluigi Barbaro

Beilstein J. Org. Chem. 2021, 17, 589–621, doi:10.3762/bjoc.17.53

• 3), whilst a high surface area around 150 m2⋅g−1 was proposed to increase the number of exposed sites [214]. Zn@TiNT afforded BHET in 87% yield at 196 °C reaction temperature. TiNT have received significant general interest in heterogeneous catalysis because of the better active-site-accessibility

One-pot multicomponent green Hantzsch synthesis of 1,2-dihydropyridine derivatives with antiproliferative activity

• Giovanna Bosica,
• Kaylie Demanuele,
• José M. Padrón and
• Adrián Puerta

Beilstein J. Org. Chem. 2020, 16, 2862–2869, doi:10.3762/bjoc.16.235

• preliminary study of the antiproliferative activity against human solid tumor cells demonstrated that 1,2-DHPs could inhibit cancer cell growth in the low micromolar range. Keywords: antiproliferative activity; 1,2-dihydropyridines; green Hantzsch synthesis; heterogeneous catalysis; one-pot multicomponent

• find a green catalyst that could provide a wide substrate scope for the Hantzsch synthesis of 1,2-dihydropyridines in a short reaction time. In order to achieve a green method, apart from utilizing a multicomponent reaction as a route providing a high atom economy, heterogeneous catalysis should be

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

• coupling; heterogeneous catalysis; nanomaterial; Introduction Over the past decades, biomass-based nanomaterials have become a highly prevalent topic of research owing to their sustainability, bioavailability, unique structural and morphological characteristics [1]. Particularly dominant in this field are

• abundant amine groups. While groups are starting to investigate the usage of chitin and chitosan-based supports for heterogeneous catalysis, there are still scarce investigations on using these biomaterials on the nanoscale, which can allow for higher accessibility of their functionalities towards better

• highly relevant in areas of research such as pharmaceuticals and materials technology [21]. Furthermore, works in heterogeneous catalysis have shown that the catalyst support plays a major role in the activity of transition-metal NPs such as Pd [7]. A model reaction was performed under the conditions

Recent applications of porphyrins as photocatalysts in organic synthesis: batch and continuous flow approaches

• Rodrigo Costa e Silva,
• Luely Oliveira da Silva,
• Aloisio de Andrade Bartolomeu,
• Timothy John Brocksom and
• Kleber Thiago de Oliveira

Beilstein J. Org. Chem. 2020, 16, 917–955, doi:10.3762/bjoc.16.83

• oxidation of amines to imines was also described using heterogeneous catalysis. Zhang and co-workers demonstrated that the MOF (SnIV)porphyrin-containing photocatalyst (UNLPF-12) can be used for the oxidation of primary amines to imines in 88–99% yields under visible light irradiation (Scheme 53) [40]. In

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

• 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

Norbornadiene-functionalized triazatriangulenium and trioxatriangulenium platforms

• Roland Löw,
• Talina Rusch,
• Tobias Moje,
• Fynn Röhricht,
• Olaf M. Magnussen and
• Rainer Herges

Beilstein J. Org. Chem. 2019, 15, 1815–1821, doi:10.3762/bjoc.15.175

• ; quadricyclane; self-assembled monolayers; TATA platform; thermal isomerization; TOTA platform; Introduction Recently, we discovered that the thermochemically forbidden cis–trans isomerization of azobenzenes can be efficiently catalysed by a very peculiar mechanism on bulk gold [1]. In heterogeneous catalysis

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

• copper catalyst dissolved in ionic liquid to four synthetic cycles. Nanotechnology coupled with heterogeneous catalysis has emerged as an efficient field of catalysis for various organic transformations. Inspired from this Bagdi et al. have reported a nano-copper oxide-mediated three-component A3

Ugi reaction-derived prolyl peptide catalysts grafted on the renewable polymer polyfurfuryl alcohol for applications in heterogeneous enamine catalysis

• Alexander F. de la Torre,
• Gabriel S. Scatena,
• Oscar Valdés,
• Daniel G. Rivera and
• Márcio W. Paixão

Beilstein J. Org. Chem. 2019, 15, 1210–1216, doi:10.3762/bjoc.15.118

• asymmetric Michael addition of n-butanal to β-nitrostyrene that was used as a model reaction. This work supports the potential of multicomponent reactions towards the assembly of catalysts and their simultaneous functionalization for immobilization. Keywords: flow chemistry; heterogeneous catalysis

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

• organic chemistry [12][13][14][15][16]. On the other hand, to reduce the toxicity and increase the efficiency, sulfonic acids are heterogenized on the various solid supports [17][18][19]. In fundamental, heterogeneous catalysis is interminably fascinating and perennially novel [20]. The few reports on

Bioinspired cobalt cubanes with tunable redox potentials for photocatalytic water oxidation and CO₂ reduction

• Zhishan Luo,
• Yidong Hou,
• Jinshui Zhang,
• Sibo Wang and
• Xinchen Wang

Beilstein J. Org. Chem. 2018, 14, 2331–2339, doi:10.3762/bjoc.14.208

• application in heterogeneous catalysis [30][31][32][33], owing to their molecular nature with flexible ligand architectures [34][35]. In this regard, extensive attention has been contributed to the design and synthesis of molecular catalysts [36]. Unfortunately, most of the high-activity molecular catalysts

Heterogeneous acidic catalysts for the tetrahydropyranylation of alcohols and phenols in green ethereal solvents

• Ugo Azzena,
• Massimo Carraro,
• Gloria Modugno,
• Luisa Pisano and
• Luigi Urtis

Beilstein J. Org. Chem. 2018, 14, 1655–1659, doi:10.3762/bjoc.14.141

• Ugo Azzena Massimo Carraro Gloria Modugno Luisa Pisano Luigi Urtis Dipartimento di Chimica e Farmacia, Università degli Studi di Sassari, via Vienna 2, 07100 – Sassari, Italy 10.3762/bjoc.14.141 Abstract The application of heterogeneous catalysis and green solvents to the set up of widely

Cobalt–metalloid alloys for electrochemical oxidation of 5-hydroxymethylfurfural as an alternative anode reaction in lieu of oxygen evolution during water splitting

• Jonas Weidner,
• Stefan Barwe,
• Kirill Sliozberg,
• Stefan Piontek,
• Justus Masa,
• Ulf-Peter Apfel and
• Wolfgang Schuhmann

Beilstein J. Org. Chem. 2018, 14, 1436–1445, doi:10.3762/bjoc.14.121

• substituted by FDCA-based polyethylene 2,5-furandicarboxylate (PEF) produced via a green chemical synthetic route. Thus, HMF oxidation would lead to a product of high economic value and ecological relevance [9]. Classically, the oxidation of HMF is performed by means of homogeneous and heterogeneous catalysis

Nanoreactors for green catalysis

• M. Teresa De Martino,
• Loai K. E. A. Abdelmohsen,
• Floris P. J. T. Rutjes and
• Jan C. M. van Hest

Beilstein J. Org. Chem. 2018, 14, 716–733, doi:10.3762/bjoc.14.61

• heterogeneous catalysis Catalysis, in general, is divided into two major types, homogenous and heterogeneous. In homogeneous catalysis catalyst and substrates are both present and molecularly dissolved in the same phase (typically a liquid phase) [46]. Homogeneous catalysis involves the use of biocatalysts

• sites are dispersed [49][50]. Homogeneous catalysis is generally performed under milder operative conditions than heterogeneous catalysis [51]. In fact, heterogeneous catalysts generally possess very high decomposition temperatures (above 100 °C) [52]. The presence of a solid phase often results in the

• formation of temperature gradients when using high temperatures, which leads to an increase in reactant diffusion and a consequent hampering of mass transfer [53]. Furthermore, the catalytic sites in heterogeneous catalysis are often not as well-defined as in homogeneous catalysis. Therefore, homogeneous

Heterogeneous Pd catalysts as emulsifiers in Pickering emulsions for integrated multistep synthesis in flow chemistry

• Katharina Hiebler,
• Georg J. Lichtenegger,
• Manuel C. Maier,
• Eun Sung Park,
• Renie Gonzales-Groom,
• Bernard P. Binks and
• Heidrun Gruber-Woelfler

Beilstein J. Org. Chem. 2018, 14, 648–658, doi:10.3762/bjoc.14.52

• . Keywords: compartmentalisation; heterogeneous catalysis; multistep flow chemistry; palladium; Pickering emulsions; Introduction Palladium (Pd) catalysis has been established as a key component in the toolbox of organic chemists. Reactions that are catalysed by palladium benefit from the remarkable

• obtained results are very promising although the relevant transformation needed higher catalyst amounts. Recyclability and metal leaching In the context of heterogeneous catalysis it is essential to investigate the actual nature of the catalysts during the reaction as well as the reusability and stability

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

• trifluoromethylation of (hetero)arenes under photoredox catalysis. Direct C–H trifluoromethylation of five- and six-membered ring (hetero)arenes using heterogeneous catalysis. Trifluoromethylation of terminal olefins. Trifluoromethylation of enamides. (E)-Selective trifluoromethylation of β-nitroalkenes under

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

• in both the oxidation and alkylation reaction reveals a potential method for the valorization of lignocellulosic biomass. Keywords: alkylation; benzyl alcohol; benzyl chloride; iron oxide; mechanochemistry; microwave-assisted oxidation; polysaccharide; toluene; Introduction Heterogeneous catalysis

• applications in heterogeneous catalysis [10][11][12][13][14]. Transition metal and metal oxide nanoparticles have been reported to be highly active and selective in several processes, such as redox [15][16][17], C–C and C–heteroatom couplings [18][19]. In particular, iron oxide nanoparticles have been the

• toluene, respectively) could find current application in the valorization of lignocellulosic biomass with heterogeneous catalysis. However, the use of heterogeneous catalysts in the aforementioned reactions usually requires a filtration or centrifugation step to recover the catalyst. In order to simplify