Decarboxylative 1,3-dipolar cycloaddition of amino acids for the synthesis of heterocyclic compounds

• Xiaofeng Zhang,
• Xiaoming Ma and
• Wei Zhang

Beilstein J. Org. Chem. 2023, 19, 1677–1693, doi:10.3762/bjoc.19.123

• ) [70]. We expected that using olefinic oxindoles 14 as alkenes for the [3 + 2] cycloaddition could afford spirooxindole-pyrrolizidines. The method development revealed that recyclable zeolite HY acid is a good catalyst for the cycloaddition [70]. Thus, the zeolite HY-catalyzed reaction of glycine with

• endo-transition state A to give spirooxindole-pyrrolizidine 17 which spontaneously reacts with another equiv of arylaldehyde to form ylide 18 in the presence of zeolite HY. The second [3 + 2] cycloaddition of 18 with 14a affords product 15a as a major product through an endo-cycloaddition and 15a’ as a

One-pot double annulations to confer diastereoselective spirooxindolepyrrolothiazoles

• Juan Lu,
• Bin Yao,
• Desheng Zhan,
• Zhuo Sun,
• Yun Ji and
• Xiaofeng Zhang

Beilstein J. Org. Chem. 2022, 18, 1607–1616, doi:10.3762/bjoc.18.171

• one-pot reactions with recyclable organocatalysts [69]. Notably, we conferred K10 acid to promote the C–H activation in the synthesis of spirooxindolepyrrolidines, and used Zeolite HY catalyst to synthesize diastereoselective dispiro[oxindolepyrrolidine]s with a butterfly shape (Scheme 1A and 1B) [70

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

• ) from citronellal (1) as test reaction (Scheme 1). Thus, citronellal (1) was cyclized to isopulegol in the heating zone. This was achieved at 80 °C in 1,4-dioxane using a Zeolite-encapsulated magnetic nickel ferrite nanoparticles (NiFe2O4@TiO2@ZSM-5) catalyst, an aluminosilicate zeolite, which gave best

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

• arenes and heteroarenes using heterogeneous catalysts In 2012, a novel strategy for the 3-cyanation of indole in the presence of Ru(III)-exchanged NaY zeolite (RuY) was reported [36]. In this reaction K4[Fe(CN)6] was utilized as the cyano source in DMF at 110 °C. The Cu(OAc)2 and O2 (1 atm) was found

• mechanism for the ruthenium-catalyzed aerobic oxidative cyanation. RuCl3-catalyzed oxidative cyanation of tertiary amines using acetone cyanohydrin as the cyanating agent. Cyanation of indoles using K4[Fe(CN)6] as cyano source and Ru(III)-exchanged NaY zeolite (RuY) as catalyst. Cyanation of arenes and

Synthesis of 5-arylacetylenyl-1,2,4-oxadiazoles and their transformations under superelectrophilic activation conditions

• Andrey I. Puzanov,
• Dmitry S. Ryabukhin,
• Anna S. Zalivatskaya,
• Dmitriy N. Zakusilo,
• Darya S. Mikson,
• Irina A. Boyarskaya and
• Aleksander V. Vasilyev

Beilstein J. Org. Chem. 2021, 17, 2417–2424, doi:10.3762/bjoc.17.158

• (TfOH), the strong Lewis acids AlX3 (X = Cl, Br), or the acidic zeolite CBV-720. Results and Discussion The synthesis of 5-arylethynyl-1,2,4-oxadiazoles 3 was based on transformations of the corresponding 5-styryloxadiazoles, i.e., 5-(2-arylethenyl)-3-aryl-1,2,4-oxadiazoles 1a–g (Scheme 1). Bromination

• zeolite CBV-720 (Table 2). However, these Lewis acids showed unsatisfactory results leading to oligomeric materials (Table 2, entries 1 and 2). Probably, due to some secondary reactions of the formed compound 5a with AlCl3, AlBr3. The yield of target compound 5a in the reaction with zeolite was lower than

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

• coated multichannel microreactor with an integrated zeolite ZSM-5 membrane (Scheme 28) [156][157]. The heterogeneous catalyst used was a Cs-exchanged faujasite NaX. The membrane maximised the outcomes in comparison to tested fixed-bed and microreactors. The ZSM-5 membrane allowed fast water exclusion

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

• p-nitrobenzaldehyde (2a) and 2,6-dimethylpyridine (1a) as model substrates. Our investigation started with the reaction of p-nitrobenzaldehyde (2a) and 2,6-dimethylpyridine (1a) in the presence of Hβ zeolite as a catalyst at 120 °C in toluene for 24 h in a sealed vial (Table 1, entry 1). However

A new method for the synthesis of diamantane by hydroisomerization of binor-S on treatment with sulfuric acid

• Rishat I. Aminov and
• Ravil I. Khusnutdinov

Beilstein J. Org. Chem. 2020, 16, 2534–2539, doi:10.3762/bjoc.16.205

• , PtO2) in glacial acetic acid under high pressure conditions at 70 °С and 200 psi of H2 [8][9]. In the presence of superacid catalysts, such as B(OSO2CF3)3, CF3SO3H/SbF5 1:1, CF3SO3H/B(OSO2CF3)3 1:1 [10], NaBH4/CF3SO3H [11], or zeolite Y in the NaH form (NaY) [12], hydrocarbons 3a–c isomerize to

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

• –proline, trimethylsilyl chloride (TMSCl), Amberlite® IR-120, indion 190, trifluoroethanol, YCl3, HClO4–SiO2, MMZY zeolite, Er(OTf)3, etc. [22][23][24][25][26][27][28][29][30]. Developments in already established multicomponent reactions (MCRs) are interesting topics in organic synthesis. For instance, the

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

• recombination [154][155]. Suárez and co-workers used the photodeposition of platinum onto tungsten oxide (WO3) powder, before immobilising within a zeolite framework to produce visible light-active HPCats for the degradation of pollutants in air [156]. Scaiano and co-workers have also utilised photodeposition

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

• ][15][16][17]. Two dimensional 2D-MFI and MWW delaminated zeolite MCM-56, which have been prepared recently [18][19][20][21], represent two types of these materials, which exhibit relatively high surface areas and high accessibility of catalytic sites on the surface as well [22]. Therefore, we

• been already described [6] and it assumed that most of Mo active species in zeolite-based catalysts are formed by reacting molybdenum oxide with Si-O(H)-Al groups [12][27]. Similarly, Lim et al. showed recently [28], that Brønsted acid sites improve dispersion of molybdenum oxide on the surface

• . Moreover, for related system based on tungsten oxide in zeolite, it was suggested using high resolution STEM that Brønsted acid sites in proximity to metathesis active sites facilitate olefin adsorption and metallocycle formation [29]. Such mechanism may be effective also for Mo catalysts. The decrease in

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

• : bisphenol A; carbon dioxide uptake; hydrogen storage; OH-containing; porous organic polymers; Introduction Porous organic polymers standing out from kinds of porous materials such as zeolite, activated carbon, metal-organic frameworks [1][2], and covalent organic frameworks [3][4], with their prominent

Sugar-based micro/mesoporous hypercross-linked polymers with in situ embedded silver nanoparticles for catalytic reduction

• Qing Yin,
• Qi Chen,
• Li-Can Lu and
• Bao-Hang Han

Beilstein J. Org. Chem. 2017, 13, 1212–1221, doi:10.3762/bjoc.13.120

• or embed the AgNPs into a supporting matrix. The loading of AgNPs on different substrates has been reported, for instance, SiO2 [23], TiO2 [24], Al2O3 [25], porous carbon [26], carbonaceous matrix [27], carboxymethyl chitosan [28], zeolite [29], cellulose [30], ZnO paper [31] and polymers such as PVP

Isosorbide and dimethyl carbonate: a green match

• Fabio Aricò and
• Pietro Tundo

Beilstein J. Org. Chem. 2016, 12, 2256–2266, doi:10.3762/bjoc.12.218

• . However, zeolites are not very efficient catalysts for the dehydration of D-sorbitol as isosorbide yields usually range between 40 to 60% [57][63][64]. Furthermore they also require high temperature, i.e., 430–533 K. Recently Fukuoka and co-workers reported a new efficent Hβ zeolite with a high Si/Al

• ratio (up to 75) that showed an improved activity and allowed dehydration of D-sorbitol into isosorbide in 76% yield at 400 K (127 °C) [65]. The Hβ zeolite can also be reused up to five times before losing its activity as catalyst. Despite this methodology being one of the most promising so far reported

Diels–Alder reactions in confined spaces: the influence of catalyst structure and the nature of active sites for the retro-Diels–Alder reaction

• Ángel Cantín,
• M. Victoria Gomez and
• Antonio de la Hoz

Beilstein J. Org. Chem. 2016, 12, 2181–2188, doi:10.3762/bjoc.12.208

• Científica Aplicada (IRICA), Avda. Camilo José Cela s/n, E-13071-Ciudad Real, Spain 10.3762/bjoc.12.208 Abstract Diels–Alder cycloaddition between cyclopentadiene and p-benzoquinone has been studied in the confined space of a pure silica zeolite Beta and the impact on reaction rate due to the concentration

• effect within the pore and diffusion limitations are discussed. Introduction of Lewis or Brønsted acid sites on the walls of the zeolite strongly increases the reaction rate. However, contrary to what occurs with mesoporous molecular sieves (MCM-41), Beta zeolite does not catalyse the retro-Diels–Alder

• ] in where different stereoisomers could be obtained. Lewis-acid centers contained within the framework of zeolite beta (Zr-β, Sn-β) are useful catalysts in the Diels–Alder reaction for the production of bio-based terephthalic acid precursors, one of the monomers for the synthesis of polyethylene

Superelectrophilic activation of 5-hydroxymethylfurfural and 2,5-diformylfuran: organic synthesis based on biomass-derived products

• Dmitry S. Ryabukhin,
• Dmitry N. Zakusilo,
• Mikhail O. Kompanets,
• Anton A.Tarakanov,
• Irina A. Boyarskaya,
• Tatiana O. Artamonova,
• Mikhail A. Khohodorkovskiy,
• Iosyp O. Opeida and
• Aleksander V. Vasilyev

Beilstein J. Org. Chem. 2016, 12, 2125–2135, doi:10.3762/bjoc.12.202

• reactions of 5-HMF (1a) with various arenes in TfOH. Additionally we investigated the reactions under the action of zeolite CBV-720, since zeolites are considered as “green” catalysts in organic synthesis [60][61][62][63][64][65][66] and the data are collected in Table 4. Similarly to the reaction with

• benzene (Table 3), 1a with other arenes yielded 5-arylmethylfurfurals 3b–o in TfOH or with zeolite CBV-720. However, the use of activated arenes, such as toluene, xylenes and pseudocumene, afforded additional Friedel–Crafts products, namely furans 4a–e (Table 4, entries 1, 2, 4–8, 11–13, and 15). These

• blocking zeolite acidic sites by π-donating arenes. Individually isolated compounds 3f and 3g being dissolved in TfOH at room temperature for 24 h gave rise to mixtures containing furans 4c and 4d along with starting 3f and 3g, respectively. This may prove that compounds 4 are the secondary reaction

Biocatalysis for the application of CO₂ as a chemical feedstock

• Apostolos Alissandratos and
• Christopher J. Easton

Beilstein J. Org. Chem. 2015, 11, 2370–2387, doi:10.3762/bjoc.11.259

• . Zeolite systems utilising Ge or Si, recently described, were able to efficiently dehydrogenate formic acid. This was guided through computational calculations, allowing the design of a zeolite catalyst displaying over 94% selectivity over the counter-productive formate dehydration reaction [145]. The

• combination of biological systems for centralised hydrogen storage through CO2 reduction as formate, with cheap zeolite catalysts for decentralised on demand hydrogen regeneration appears a very promising sustainable approach toward a hydrogen economy (Figure 6). In vitro production of CO with CODH Reduction

Ru complexes of Hoveyda–Grubbs type immobilized on lamellar zeolites: activity in olefin metathesis reactions

• Hynek Balcar,
• Naděžda Žilková,
• Martin Kubů,
• Michal Mazur,
• Zdeněk Bastl and
• Jiří Čejka

Beilstein J. Org. Chem. 2015, 11, 2087–2096, doi:10.3762/bjoc.11.225

• ) not allowing to anchor appropriate alkylidene complexes in the channel system and to ensure accessibility of catalytic centers by reactants. However, new methods for the preparation of lamellar (also called two-dimensional) zeolite with high surface area and layered structure have been developed [23

• the prepared zeolite, the individual zeolitic layers exhibit or do not exhibit micropore character. Two dimensional zeolites are usually prepared by a bottom-up hydrothermal synthesis [26]; recently also a top-down approach from germanosilicate zeolite UTL was reported [27]. The latter approach

• zeolites MCM-22, MCM-56, and MCM-36. Linker-free immobilizations, consisting in mixing zeolite supports with catalyst solutions and stirring the corresponding suspensions at room temperature, were successfully used. Hybrid catalysts formed (Ru content from 0.7 to 1.1 wt %) exhibited a firm attachment of Ru

Continuous flow nitration in miniaturized devices

• Amol A. Kulkarni

Beilstein J. Org. Chem. 2014, 10, 405–424, doi:10.3762/bjoc.10.38

• be overlooked without focusing entirely on using the “micro reactor” concept. 3.1.4 Nitration with solid acid catalysts. The continuous flow vapour phase nitration using a solid acid catalyst has also been explored [26]. It is known that the solid acid catalysts, i.e., ZSM and other zeolite catalysts

Practical synthesis of indoles and benzofurans in water using a heterogeneous bimetallic catalyst

• Cybille Rossy,
• Eric Fouquet and
• François-Xavier Felpin

Beilstein J. Org. Chem. 2013, 9, 1426–1431, doi:10.3762/bjoc.9.160

• CuI [19][20][21]. Alternatively, copper-free heterogeneous catalysis has been proposed thanks to the Lewis acid properties of zeolite [(NH4)Y] used as support [22][23][24]. A challenging approach consisting of a heterobimetallic catalysis has been occasionally envisaged. This area was pioneered by the

Metal-free aerobic oxidations mediated by N-hydroxyphthalimide. A concise review

• Lucio Melone and
• Carlo Punta

Beilstein J. Org. Chem. 2013, 9, 1296–1310, doi:10.3762/bjoc.9.146

• -electron-transfer interaction of antraquinone (AQ) with NHPI in zeolite HY, followed by hydrogen-atom transfer, successfully led to the formation of the PINO radical, which in turn was responsible for the propagation of the radical chain in the selective oxidation of ethylbenzene to the corresponding

• zeolite, for the oxygenation of a wider range of hydrocarbons [34]. Moreover, the electronic effect of substituents on quinones and on the aromatic ring of NHPI was also investigated. Quinones bearing halogen groups were used in the selective oxidation of alkylarenes, alkenes and alkanes [35], revealing

Mild and efficient cyanuric chloride catalyzed Pictet–Spengler reaction

• Ashish Sharma,
• Mrityunjay Singh,
• Nitya Nand Rai and
• Devesh Sawant

Beilstein J. Org. Chem. 2013, 9, 1235–1242, doi:10.3762/bjoc.9.140

• Brønsted acids. However, recently several other aprotic or Lewis acids, such as Yb(OTf)3 [23][24][25], AuCl3/AgOTf [26], Me3SiCl [27][28], BF3·Et2O [29], iodine [30], zeolite [31] and enzymes [32][33][34], have been used for carrying out the Pictet–Spengler reaction. Though the Pictet–Spengler reaction has

Iron-containing mesoporous aluminosilicate catalyzed direct alkenylation of phenols: Facile synthesis of 1,1-diarylalkenes

• Satyajit Haldar and
• Subratanath Koner

Beilstein J. Org. Chem. 2013, 9, 49–55, doi:10.3762/bjoc.9.6

• the iron center in the catalyst Fe-Al-MCM-41. NaY, a microporous aluminosilicate, did not yield any product under the specified reaction conditions (Table 2, entry 1). Sartori et al. reported an electrophilic alkenylation of aromatics with phenylacetylene over zeolite HSZ-360-Y; however, this zeolite

• pretreatment is necessary to activate the catalyst and a moisture-free medium is essential. Furthermore, a higher temperature (110 °C) and a longer reaction time (14 h) were also required for the catalytic reaction. Sartori et. al. suggested that the external surface of HSZ-360-Y zeolite was responsible for

• such catalytic activity rather than the pore of the zeolite. As evidence, they reported the acidic-alumina-catalyzed reaction in which only 25% product yield was observed [43]. However, when we used acidic alumina (under our reaction conditions) at a relatively low temperature (80 °C) without any

Coupled chemo(enzymatic) reactions in continuous flow

• Ruslan Yuryev,
• Simon Strompen and
• Andreas Liese

Beilstein J. Org. Chem. 2011, 7, 1449–1467, doi:10.3762/bjoc.7.169

• immobilized Candida antarctica lipase B (Novozym 435) was used as a heterogeneous catalyst in the kinetic resolution of the alcohol 22 [30]. Racemization of the unreacted (S)-22 was achieved with acidic zeolite catalysts. Both heterogenous catalysts were coated with ionic liquids for improved stability of the

• lipase in the presence of the acidic chemocatalysts and for reduction of zeolite-catalyzed side reactions [30][31]. The substrates and supercritical CO2 were fed continuously, thus omitting the use of organic solvents for product extraction. An enantiomeric excess of 97% was achieved for the product (R

• resolution of (rac)-1-phenylethanol (22) in supercritical CO2 in a packed-bed reactor loaded with acidic zeolite (A) and Novozym 435 (E) [30]. Synthesis of D-xylulose (28) from D,L-serine (26) and D,L-glyceraldehyde (25) in a continuously operated enzyme membrane reactor. E1: D-Amino acid oxidase; E2

Efficient and selective chemical transformations under flow conditions: The combination of supported catalysts and supercritical fluids

• M. Isabel Burguete,
• Eduardo García-Verdugo and
• Santiago V. Luis

Beilstein J. Org. Chem. 2011, 7, 1347–1359, doi:10.3762/bjoc.7.159

• mixture of zeolite CP811E-150 as the acid catalyst for the racemization and CALB supported on a SILLP based on bead-type PS-DVB resins [106]. Good results were obtained when the zeolite catalyst was coated with a small amount of an IL. This follows the same trend observed in the case of SILPs