Diastereoselective synthesis of highly substituted cyclohexanones and tetrahydrochromene-4-ones via conjugate addition of curcumins to arylidenemalonates

• Deepa Nair,
• Abhishek Tiwari,
• Banamali Laha and
• Irishi N. N. Namboothiri

Beilstein J. Org. Chem. 2024, 20, 2016–2023, doi:10.3762/bjoc.20.177

• [26][29]. In order to demonstrate the synthetic utility of our methodology, we performed a scale-up reaction with representative starting materials, viz. 1a and 2b on a 1.0 mmol scale (Scheme 3). The reaction required slightly more time and resulted in the corresponding double and triple Michael

• reported in due course. Biologically active derivatives of cyclohexanones. X-ray structure of 4a (CCDC 2351387). Origin of stereoselectivity in the double Michael addition. The Michael donor–acceptor reactivity of curcumin: previous vs present work. A plausible reaction mechanism. Scale-up reaction

Development of a flow photochemical process for a π-Lewis acidic metal-catalyzed cyclization/radical addition sequence: in situ-generated 2-benzopyrylium as photoredox catalyst and reactive intermediate

• Masahiro Terada,
• Zen Iwasaki,
• Ryohei Yazaki,
• Shigenobu Umemiya and
• Jun Kikuchi

Beilstein J. Org. Chem. 2024, 20, 1973–1980, doi:10.3762/bjoc.20.173

• scale-up, are the advantages of using a flow system. In addition, reproducibility in a liquid–liquid flow system is improved because the flow velocity and temperature can be precisely controlled by using a syringe pump and a temperature control unit, respectively. Moreover, as the reaction mixture

Benzylic C(sp³)–H fluorination

• Alexander P. Atkins,
• Alice C. Dean and
• Alastair J. J. Lennox

Beilstein J. Org. Chem. 2024, 20, 1527–1547, doi:10.3762/bjoc.20.137

• fluorination of primary, secondary and tertiary benzylic substrates. The methodology was amenable to scale up, demonstrating the gram-scale synthesis of product 15 in 85% yield. The authors recognised the difficulty in sequential fluorination and noted that the use of a more electron-rich photocatalyst would

• showed they were able to scale-up and selectively fluorinate the ibuprofen methyl ester at the methylene group to produce over 2 g of product 12. The utility of the benzyl fluoride products as strategic intermediates for benzylation of electron-rich arenes was demonstrated by the authors (Figure 41B

Synthesis of 2-benzyl N-substituted anilines via imine condensation–isoaromatization of (E)-2-arylidene-3-cyclohexenones and primary amines

• Lu Li,
• Na Li,
• Xiao-Tian Mo,
• Ming-Wei Yuan,
• Lin Jiang and
• Ming-Long Yuan

Beilstein J. Org. Chem. 2024, 20, 1468–1475, doi:10.3762/bjoc.20.130

• acceptable to high yields. Mild reaction conditions, no requirement of metal catalysts, operational simplicity and the potential for scale-up production are some of the highlighted advantages of this transformation. Keywords: aniline; (E)-2-arylidene-3-cyclohexenone; imine condensation; isoaromatization

• further demonstrated. As depicted in Scheme 5, we first attempted scale-up synthesis of product 4aa. Pleasingly, when starting from 2a on a 6.0 mmol scale, the product 4aa was afforded in 74% yield. We also conducted the successive synthesis of 4aa in a manner of one-pot procedure. On the condition of

Selectfluor and alcohol-mediated synthesis of bicyclic oxyfluorination compounds by Wagner–Meerwein rearrangement

• Ziya Dağalan,
• Muhammed Hanifi Çelikoğlu,
• Saffet Çelik,
• Ramazan Koçak and
• Bilal Nişancı

Beilstein J. Org. Chem. 2024, 20, 1462–1467, doi:10.3762/bjoc.20.129

• mmol), scale-up experiments were conducted. The isolated yield of 4b (1.26 g, 90% yield) is quite satisfactory, as can be seen from Scheme 3. For the fluoroalkoxylation, we propose the mechanism given in Scheme 4. In this mechanism, first the double bond in (+)-camphene attacks the fluorine in the

• alcohol in 2 mL of CH3CN at 90 °C for 2 h. Isolated yields. Scale-up experiments. Reaction conditions: (+)-Camphene (1b) (1.0 g, 7.34 mmol), selectfluor (3.12 g, 8.81 mmol), MeOH (17.62 mmol), CH3CN (20 mL), 90 °C, 2 h. Proposed mechanism for fluoroalkoxylation of (+)-camphene by Wagner–Meerwein

Synthesis of 4-functionalized pyrazoles via oxidative thio- or selenocyanation mediated by PhICl₂ and NH₄SCN/KSeCN

• Jialiang Wu,
• Haofeng Shi,
• Xuemin Li,
• Jiaxin He,
• Chen Zhang,
• Fengxia Sun and
• Yunfei Du

Beilstein J. Org. Chem. 2024, 20, 1453–1461, doi:10.3762/bjoc.20.128

• selenocyanated products 3a–o achieved in acceptable to good yields. Similarly, the selenocyanation of C3- and C5-unsubstituted substrate 1p regioselectively furnished the 4-selenocyanated pyrazole 3p in good yield. The utility of this approach was further demonstrated by a scale-up experiment. When 10.0 mmol of

Palladium-catalyzed three-component radical-polar crossover carboamination of 1,3-dienes or allenes with diazo esters and amines

• Geng-Xin Liu,
• Xiao-Ting Jie,
• Ge-Jun Niu,
• Li-Sheng Yang,
• Xing-Lin Li,
• Jian Luo and
• Wen-Hao Hu

Beilstein J. Org. Chem. 2024, 20, 661–671, doi:10.3762/bjoc.20.59

• -amino acid derivative. This approach proceeds under mild and simple reaction conditions and shows high functional group tolerance, especially in the incorporation of various bioactive molecules. The studies on scale-up reactions and diverse derivatizations highlight the practical utility of this

• , providing another type of hybrid allylPd radical IV. After the equilibrium shifting to the π-allyl complex V, the unsaturated γ-AA derivative 6 would be obtained with the nucleophilic attack of amine 3. The utility of this protocol was further highlighted by scale-up reactions and diverse derivatizations of

• the first reaction mode for a difunctionalization of alkenes with diazo compounds via a radical-polar crossover process. This synthetic transformation proceeds under mild reaction conditions and shows high functional group tolerance. The studies on late-stage functionalization, scale-up reactions, and

HPW-Catalyzed environmentally benign approach to imidazo[1,2-a]pyridines

• Luan A. Martinho and
• Carlos Kleber Z. Andrade

Beilstein J. Org. Chem. 2024, 20, 628–637, doi:10.3762/bjoc.20.55

• scale-up of the HPW-catalyzed GBB reaction (5.0 mmol) between 2-aminopyridine (1a), 4-nitrobenzaldehyde (2a) and cyclohexyl isocyanide (3) in EtOH under μw heating. Plausible reaction mechanism for the HPW-catalyzed GBB reaction. Optimization of the reaction conditions.a Comparison of reaction

Synthesis of 2,2-difluoro-1,3-diketone and 2,2-difluoro-1,3-ketoester derivatives using fluorine gas

• Alexander S. Hampton,
• David R. W. Hodgson,
• Graham McDougald,
• Linhua Wang and
• Graham Sandford

Beilstein J. Org. Chem. 2024, 20, 460–469, doi:10.3762/bjoc.20.41

• quinuclidine to direct fluorination reactions of 1,3-diketone and 1,3-ketoester substrates using fluorine gas can give difluorinated products by a simple batch process, offering a potentially valuable route to the synthesis of difluoromethylene compounds that is suitable for inexpensive scale-up. Results 2

Nucleophilic functionalization of thianthrenium salts under basic conditions

• Xinting Fan,
• Duo Zhang,
• Xiangchuan Xiu,
• Bin Xu,
• Yu Yuan,
• Feng Chen and
• Pan Gao

Beilstein J. Org. Chem. 2024, 20, 257–263, doi:10.3762/bjoc.20.26

• atmosphere. Isolated yields. Substrate scope of amines. Reaction conditions: alkylthianthrenium salts 1 (0.3 mmol), amines 2 (0.2 mmol), DIPEA (0.4 mmol) in 2.0 mL of MeCN at 80 °C for 16 h under air atmosphere. Isolated yields. Scale-up reaction. Optimization of the thioetherification of S-(alkyl

Copper-catalyzed multicomponent reaction of β-trifluoromethyl β-diazo esters enabling the synthesis of β-trifluoromethyl N,N-diacyl-β-amino esters

• Youlong Du,
• Haibo Mei,
• Ata Makarem,
• Ramin Javahershenas,
• Vadim A. Soloshonok and
• Jianlin Han

Beilstein J. Org. Chem. 2024, 20, 212–219, doi:10.3762/bjoc.20.21

• catalytic cycle. Finally, the acetimidic anhydride D undergoes a Mumm rearrangement to furnish the desired β-trifluoromethyl diacylamino ester 4a. The final goal of this work is the examination of the scale-up applicability of this three-component tandem reaction (Scheme 5). To our delight, the reaction

• . Control experiments. Proposed reaction mechanism. Scale-up synthesis. Optimization of reaction conditions.a Supporting Information Supporting Information File 8: Experimental details and spectral data. Funding We gratefully acknowledge the financial support from the National Natural Science Foundation

Optimizing reaction conditions for the light-driven hydrogen evolution in a loop photoreactor

• Pengcheng Li,
• Daniel Kowalczyk,
• Johannes Liessem,
• Mohamed M. Elnagar,
• Dariusz Mitoraj,
• Radim Beranek and
• Dirk Ziegenbalg

Beilstein J. Org. Chem. 2024, 20, 74–91, doi:10.3762/bjoc.20.9

• due to extended ion transport distances. These effects cause significant potential losses, eventually reducing the efficiency of the reactors. The addition of large amounts of supporting electrolyte and vigorous circulation of the electrolyte solution also complicates the scale-up process [17][18]. On

• the contrary, expanding photocatalytic systems, particularly those employing powdered photocatalysts, to a larger scale is notably more straightforward [17][18]. However, complications arise when attempting to scale up reactors solely based on geometric similarity, as alterations in mixing and

• hydrodynamic attributes occur during the process of scale-up [19][20]. Therefore, a suitable reactor, which ensures excellent fluid dynamics and transport properties during scale-up, is needed for photocatalytic hydrogen generation. Loop reactors utilize partial inner circulation of the chosen reaction medium

Secondary metabolites of Diaporthe cameroonensis, isolated from the Cameroonian medicinal plant Trema guineensis

• Bel Youssouf G. Mountessou,
• Élodie Gisèle M. Anoumedem,
• Blondelle M. Kemkuignou,
• Yasmina Marin-Felix,
• Frank Surup,
• Marc Stadler and
• Simeon F. Kouam

Beilstein J. Org. Chem. 2023, 19, 1555–1561, doi:10.3762/bjoc.19.112

• ) profile, was scale up fermented to give 12 g of culture extract. This extract was subjected to a silica gel column chromatography to give several fractions, which were further purified over normal and reversed-phase HPLC to yield 2-ethyl-2,6-dihydroxy-5,7-dimethylbenzofuran-3-one (1), 3,9

Morpholine-mediated defluorinative cycloaddition of gem-difluoroalkenes and organic azides

• Tzu-Yu Huang,
• Mario Djugovski,
• Sweta Adhikari,
• Destinee L. Manning and
• Sudeshna Roy

Beilstein J. Org. Chem. 2023, 19, 1545–1554, doi:10.3762/bjoc.19.111

• azido amine intermediate INT-3 can be formed via vinylic substitution of INT-1 with an azide which can cyclize to form INT-4 that subsequently aromatizes to afford product 3 (route B). To demonstrate the applicability of this method, a scale-up reaction was performed using 150 mg of the limiting reagent

• , which is five times the usual reaction scale used in substrate scope screening or optimization experiments (Figure 6). In this scale-up experiment, we obtained the product with 57% yield , which is slightly lower than 70% using 1-(2,2-difluorovinyl)-4-methylbenzene (1, 154 mg, 1 mmol, 1 equiv), 4

• . Proposed mechanism. Scale-up experiment. Optimization of reaction conditions.a Supporting Information Supporting Information File 2: General information, experimental procedures for all the substrates and intermediates, characterization data, and NMR spectra (1H, 19F, and 13C NMR). Funding Research

Selective and scalable oxygenation of heteroatoms using the elements of nature: air, water, and light

• Damiano Diprima,
• Hannes Gemoets,
• Stefano Bonciolini and
• Koen Van Aken

Beilstein J. Org. Chem. 2023, 19, 1146–1154, doi:10.3762/bjoc.19.82

• protocol demonstrates excellent scalability, as we have successfully transferred it to the HANU flow reactor. This flow photoreactor is designed for multi-phase reactions (solid–liquid, gas–liquid) [30][31][32], and allows for seamless scale-up to production scale. Finally, by the use of specific “easy to

Photoredox catalysis harvesting multiple photon or electrochemical energies

• Mattia Lepori,
• Simon Schmid and
• Joshua P. Barham

Beilstein J. Org. Chem. 2023, 19, 1055–1145, doi:10.3762/bjoc.19.81

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

• light-responsive intertwined materials and the industrial scale-up production usually hindered by the low yield of the interlocked molecules. Thus, future research efforts should be focused on the development of novel synthetic methodologies to access to such interlocked architecture, as well as the use

Honeycomb reactor: a promising device for streamlining aerobic oxidation under continuous-flow conditions

• Masahiro Hosoya,
• Yusuke Saito and
• Yousuke Horiuchi

Beilstein J. Org. Chem. 2023, 19, 752–763, doi:10.3762/bjoc.19.55

• high mixing efficiency throughout the reaction. This complex equipment complicates its versatile application for the scale-up and manufacturing, which leads to higher costs. To address this issue, we turned our attention to the use of porous material, which is widely used for exhaust gas treatment in

Enolates ambushed – asymmetric tandem conjugate addition and subsequent enolate trapping with conventional and less traditional electrophiles

• Péter Kisszékelyi and
• Radovan Šebesta

Beilstein J. Org. Chem. 2023, 19, 593–634, doi:10.3762/bjoc.19.44

• structurally different Michael acceptors were successfully applied. Their work also included a 3 mmol scale-up (62%, 87% ee, dr >20:1) and various derivatizations of the Mannich products. Furthermore, they have also attempted a multi-electrophile cascade reaction, which harnesses the nucleophilic nature of the

• thoroughly examined using DFT calculations. Other than the broad substrate scope, the synthetic utility of this method was demonstrated by a scale-up reaction (3.73 mmol scale, 87% yield, 88% ee), and by several different transformations of the tandem products. Similarly, Ghorai et al. studied a Cu-catalyzed

• cascade borylation/Michael addition sequence leading to enantioenriched spiroindane boronates 174 (Scheme 44A) [85]. The reaction showed good functional group tolerance. Further derivatization, as well as scale-up (1 mmol) of the reaction were successfully performed (72% yield, 89% ee, dr >20:1). Based on

C3-Alkylation of furfural derivatives by continuous flow homogeneous catalysis

• Grédy Kiala Kinkutu,
• Catherine Louis,
• Myriam Roy,
• Juliette Blanchard and
• Julie Oble

Beilstein J. Org. Chem. 2023, 19, 582–592, doi:10.3762/bjoc.19.43

• processes rely on the use of a homogeneous metal catalyst at elevated temperatures necessary to cleave the C3–H bond by oxidative addition. These experimental conditions, easily used in the laboratory, are potentially problematic for scale-up due to efficiency and safety issues (related to the high

• , not only a unique control of reaction parameters, such as improved mass and heat transfer, but also reduced safety risks and increased reproducibility of the results [29][35][36]. These features should therefore allow us to scale up our directed C3-functionalizations of furfurylimines under safe

A new oxidatively stable ligand for the chiral functionalization of amino acids in Ni(II)–Schiff base complexes

• Alena V. Dmitrieva,
• Oleg A. Levitskiy,
• Yuri K. Grishin and
• Tatiana V. Magdesieva

Beilstein J. Org. Chem. 2023, 19, 566–574, doi:10.3762/bjoc.19.41

• stereoselectivity level. Additionally, Schiff base derivatives of L7 have a considerably higher solubility in acetonitrile as compared to the L4-based complexes (see Table 3 and Supporting Information File 1); this makes it easier to scale-up the synthesis (e.g., for the SN2 alkylations or nucleophilic addition

Total synthesis of insect sex pheromones: recent improvements based on iron-mediated cross-coupling chemistry

• Eric Gayon,
• Guillaume Lefèvre,
• Olivier Guerret,
• Adrien Tintar and
• Pablo Chourreu

Beilstein J. Org. Chem. 2023, 19, 158–166, doi:10.3762/bjoc.19.15

• halides was observed and the cross-coupling products were afforded in good to excellent yields (Scheme 5). Moreover, this reaction can also be carried out at the gram scale (up to 50 mmol for alkyl–alkenyl coupling reactions, up to 10 mmol for alkyl–aryl couplings). Alkoxide salts, such as EtOMgCl, are

Synthetic study toward tridachiapyrone B

• Morgan Cormier,
• Florian Hernvann and
• Michaël De Paolis

Beilstein J. Org. Chem. 2022, 18, 1741–1748, doi:10.3762/bjoc.18.183

• yield but the scale-up of the reaction was less efficient [33]. It has to be underlined that all attempts, using either methods, to couple aldehyde 9 with 2-methylpent-1-en-3-one and directly produce 13 were unsuccessful. To achieve this goal a methylation step of 12 (LiN(iPr)2 (LDA); MeI) was thus

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

• chemistry tools developed in academia. Keywords: flow synthesis; inline purification; process development; reaction telescoping; scale-up; Introduction Continuous flow chemistry is a mature and widely applied platform technology that exploits intrinsic advantages over batch processing such as better heat

• system for purifying mixtures in a continuous fashion by using alternating sample loops and chromatography columns (Scheme 1). This system thus acts as a scale-up preparative HPLC. Two different sample loops are loaded with the crude reaction mixture, and therefore, the crude material is injected into

• of alcohols using a phase transfer catalyst (PTC) [55]. In a scale-up run, a three-stage counter-current cascade was used downstream of the first separation to remove the PTC (Scheme 4). In this scenario more than 90% of the phase transfer catalyst was separated from the phase containing the desired

An alternative C–P cross-coupling route for the synthesis of novel V-shaped aryldiphosphonic acids

• Stephen J. I. Shearan,
• Enrico Andreoli and
• Marco Taddei

Beilstein J. Org. Chem. 2022, 18, 1518–1523, doi:10.3762/bjoc.18.160

• of us, was limited to 0.543 g (1 mmol) of substrate. Scale up of this protocol was not attempted, but it might become problematic due to issues with microwave penetration in a medium that contains a strong absorber, such as the Ni catalytic complex. In this work, we have employed either 5.0 g (15.3