Redox-active molecules as organocatalysts for selective oxidative transformations – an unperceived organocatalysis field

• Elena R. Lopat’eva,
• Igor B. Krylov,
• Dmitry A. Lapshin and
• Alexander O. Terent’ev

Beilstein J. Org. Chem. 2022, 18, 1672–1695, doi:10.3762/bjoc.18.179

• include their synthetic availability, wide opportunities for rational structure design, generally lower toxicity, air and water stability, metal-free nature, and the scalability of their production and use. These features have made organocatalysis a prospering area and an even more promising methodology

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

• note here that the system is kept under a constant flow of either argon or nitrogen, mainly to avoid side reactions with components in the air (humidity, oxygen), but also to prevent the solid in the addition funnel from contacting any vapour and turning soggy before it is added to the round-bottomed

Cyclometalated iridium complexes-catalyzed acceptorless dehydrogenative coupling reaction: construction of quinoline derivatives and evaluation of their antimicrobial activities

• Hongling Shui,
• Yuhong Zhong,
• Renshi Luo,
• Zhanyi Zhang,
• Jiuzhong Huang,
• Ping Yang and
• Nianhua Luo

Beilstein J. Org. Chem. 2022, 18, 1507–1517, doi:10.3762/bjoc.18.159

• synthesize and stable to air [36], and have good operability and reproducibility [37][38]. In recent years, our research group has carried out relevant research on ADC reactions catalyzed by cyclometalated iridium complexes and obtained some interesting research results [39]. In previous studies [39][40][41

Naphthalimide-phenothiazine dyads: effect of conformational flexibility and matching of the energy of the charge-transfer state and the localized triplet excited state on the thermally activated delayed fluorescence

• Kaiyue Ye,
• Liyuan Cao,
• Davita M. E. van Raamsdonk,
• Zhijia Wang,
• Jianzhang Zhao,
• Daniel Escudero and
• Denis Jacquemin

Beilstein J. Org. Chem. 2022, 18, 1435–1453, doi:10.3762/bjoc.18.149

• S26). As a preliminary study to assess the existence of TADF for the dyads and the triad, the fluorescence spectra of the compounds in N2-saturated and air-saturated solution were recorded (Figure 3 and Figure S27 in Supporting Information File 1). For both NI-PTZ and NI-PTZ2, the fluorescence

• . Fluorescence spectra of (a) NI-PTZ, (b) NI-PTZ-O, (c) NI-PTZ2, and (d) NI-Ph-PTZ in HEX under different atmospheres (N2, air). Optically matched solutions were used, A = 0.100, λex = 330 nm, c = 1.0 × 10−5 M, 20 °C. Fluorescence lifetime of NI-PTZ under (a) N2 atmosphere and (d) air atmosphere (λem = 610 nm, c

• = 5.0 × 10−5 M). Fluorescence lifetime of NI-PTZ2 under (b) N2 atmosphere and (e) air atmosphere (λem = 610 nm, c = 5.0 × 10−5 M). Fluorescence lifetime of (c) NI-PTZ-O (λem = 472 nm, c = 1.0 × 10−5 M) and (f) NI-Ph-PTZ (λem = 482 nm, c = 1.0 × 10−5 M). Excited with a picoseconds pulsed laser (λex = 340

Sinensiols H–J, three new lignan derivatives from Selaginella sinensis (Desv.) Spring

• Qinfeng Zhu,
• Beibei Gao,
• Qian Chen,
• Tiantian Luo,
• Guobo Xu and
• Shanggao Liao

Beilstein J. Org. Chem. 2022, 18, 1410–1415, doi:10.3762/bjoc.18.146

• Medical University. Extraction and isolation The air-dried powder of the whole plants of S. sinensis (5.2 kg) was extracted three times with 95% ethanol at room temperature. The combined extracts were concentrated and yielded 423 g of a crude extract which was subjected to reversed-phase MPLC (MCI; MeOH

Cyclodextrin-based Schiff base pro-fragrances: Synthesis and release studies

• Attila Palágyi,
• Jindřich Jindřich,
• Juraj Dian and
• Sophie Fourmentin

Beilstein J. Org. Chem. 2022, 18, 1346–1354, doi:10.3762/bjoc.18.140

• benzaldehyde) and static headspace-gas chromatography (for benzaldehyde, heptanal, and 5-methylfurfural). The aldehyde release rate from the imine was shown to depend substantially on the pH from the solution and the air humidity from the solid state. Keywords: aldehyde; controlled release; cyclodextrin

Ionic multiresonant thermally activated delayed fluorescence emitters for light emitting electrochemical cells

• Merve Karaman,
• Abhishek Kumar Gupta,
• Subeesh Madayanad Suresh,
• Tomas Matulaitis,
• Lorenzo Mardegan,
• Daniel Tordera,
• Henk J. Bolink,
• Sen Wu,
• Stuart Warriner,
• Ifor D. Samuel and
• Eli Zysman-Colman

Beilstein J. Org. Chem. 2022, 18, 1311–1321, doi:10.3762/bjoc.18.136

• fluorescence; Introduction Light-emitting electrochemical cells (LEECs) are thin film light-emitting devices typically consisting of an emissive layer containing ionic species that facilitate charge transport and an emissive semiconductor material. The emissive layer is sandwiched between two air-stable

• for other donor decorated MR-TADF emitters [34][35][36]. The photoluminescence quantum yield, ΦPL, in MeCN for DiKTa-OBuIm is 48% which decreases in air to 34%. The emission is much weaker in DiKTa-DPA-OBuIm, reflecting both the smaller oscillator strength of the transition to S1 and the greater non

• -radiative decay due to the energy gap law (ΦPL = 11% and 7% under vacuum and in air, respectively) in MeCN [37]. The S1 and T1 levels were measured from the onsets of fluorescence (2.66 eV) and phosphorescence spectra (2.41 eV) in 2-MeTHF glass at 77 K (Figure S26, Supporting Information File 1). DiKTa

Mechanochemical bottom-up synthesis of phosphorus-linked, heptazine-based carbon nitrides using sodium phosphide

• Blaine G. Fiss,
• Georgia Douglas,
• Michael Ferguson,
• Jorge Becerra,
• Jesus Valdez,
• Trong-On Do,
• Tomislav Friščić and
• Audrey Moores

Beilstein J. Org. Chem. 2022, 18, 1203–1209, doi:10.3762/bjoc.18.125

• following milling and aging, can also have occurred. Additionally, the phosphorus 2p signal in g-h-PCN showed the majority of phosphorus exists as a mixture of P=O and P–O species, with a major peak centered at 133.6 eV (69%, Figure 2c). These species are formed by oxidation with air and hydrolysis upon

• thermal stability upwards of 200 °C through TGA in nitrogen and air (Supporting Information File 1, Figures S6 and S7). The initial loss seen for both samples is attributed to surface-bound water and carbon dioxide. The g-h-PCN300 retains more mass to upwards of 400 °C in both air and nitrogen, however

• , at higher temperature (>500 °C), g-h-PCN shows an additional loss of ≈5 wt % compared to g-h-PCN. Overall, under both air and nitrogen, the g-h-PCN retains between 25–35% of its relative mass, up to 800 °C. Photochemical activity The photochemical behavior of both g-h-PCN (Supporting Information File

Lewis acid-catalyzed Pudovik reaction–phospha-Brook rearrangement sequence to access phosphoric esters

• Jin Yang,
• Dang-Wei Qian and
• Shang-Dong Yang

Beilstein J. Org. Chem. 2022, 18, 1188–1194, doi:10.3762/bjoc.18.123

• with highly air-sensitive and hazardous phosphorus halides, with the assistance of a suitable base [19][20][21][22][23][24]. As an alternative pathway, the phospha-Brook rearrangement [25][26][27][28][29][30] represents a green approach to phosphoric esters since it uses α-hydroxyphosphonates, which

Electrochemical formal homocoupling of sec-alcohols

• Kosuke Yamamoto,
• Kazuhisa Arita,
• Masashi Shiota,
• Masami Kuriyama and
• Osamu Onomura

Beilstein J. Org. Chem. 2022, 18, 1062–1069, doi:10.3762/bjoc.18.108

• are summarized in Table 1. The electrolysis was carried out using an undivided cell in the presence of Et4NBr as an electrolyte with a mixed solvent of MeCN and H2O under air atmosphere. When 4 F/mol of electricity was passed through the reaction mixture using two platinum electrodes at 0 ºC, the

• /mol, 0 °C, under air. a100 mA cc. b6 F/mol, imidazole (0.075 equiv). c6 F/mol. d8 F/mol, imidazole (0.1 equiv) e8 F/mol, MeCN/MeOH (4:1, 5 mL) without H2O. Investigation of cross-coupling reaction. Large-scale experiment. Control experiments. aDetermined by 1H NMR using 1,3,5-trimethoxybenzene as an

Automated grindstone chemistry: a simple and facile way for PEG-assisted stoichiometry-controlled halogenation of phenols and anilines using N-halosuccinimides

• Dharmendra Das,
• Akhil A. Bhosle,
• Amrita Chatterjee and
• Mainak Banerjee

Beilstein J. Org. Chem. 2022, 18, 999–1008, doi:10.3762/bjoc.18.100

• -halosuccinimides as the reagent. In the protocol, PEG-400 was used as an LAG agent and the reactions were conducted in an automated grinder in open-air at room temperature for quick access to halogenated derivatives. A wide range of substrates was compatible with NXS (X = Br, I, Cl) for electrophilic aryl

First example of organocatalysis by cathodic N-heterocyclic carbene generation and accumulation using a divided electrochemical flow cell

• Daniele Rocco,
• Ana A. Folgueiras-Amador,
• Richard C. D. Brown and
• Marta Feroci

Beilstein J. Org. Chem. 2022, 18, 979–990, doi:10.3762/bjoc.18.98

• Sigma-Aldrich and Alfa Aesar and used as received. All air/moisture sensitive reactions were carried out under an inert atmosphere, in oven-dried or flame-dried glassware. TLC was performed on aluminium plates precoated with silica gel 60 with an F254 indicator; visualized under UV light (254 nm) and/or

Synthesis of novel alkynyl imidazopyridinyl selenides: copper-catalyzed tandem selenation of selenium with 2-arylimidazo[1,2-a]pyridines and terminal alkynes

• Mio Matsumura,
• Kaho Tsukada,
• Kiwa Sugimoto,
• Yuki Murata and
• Shuji Yasuike

Beilstein J. Org. Chem. 2022, 18, 863–871, doi:10.3762/bjoc.18.87

• °C under air atmosphere. After the reaction was completed, the mixture was allowed to cool to room temperature. Then, the alkyne (3, 1.0 mmol, 1 equiv) and Na2CO3 (212 mg, 2.0 mmol, 2 equiv) were added and the mixture was stirred at room temperature. After the reaction was completed, the reaction

Palladium-catalyzed solid-state borylation of aryl halides using mechanochemistry

• Koji Kubota,
• Emiru Baba,
• Tamae Seo,
• Tatsuo Ishiyama and
• Hajime Ito

Beilstein J. Org. Chem. 2022, 18, 855–862, doi:10.3762/bjoc.18.86

• high yields. Notably, all experimental operations could be performed in air, and did not require the use of large amounts of dry and degassed organic solvents. The utility of this method was further demonstrated by gram-scale synthesis under solvent-free, mechanochemical conditions. Keywords: ball

• faster reaction kinetics than those under conventional solution-based conditions because of the high concentration; further, the experimental operations can be carried out in air. Considering these achievements, including our recent success in solid-state cross-coupling chemistry, we envisioned that this

• carried out in air without the requirement of Schlenk-line techniques or glovebox operations. Therefore, the present solid-state approach is a practical and sustainable method to complement conventional solution-based protocols. The application of this method to the solid-state borylation of insoluble

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

• 400 °C exposed to an air flow. The importance of this study is the fact that no activating agents are required and water is the only byproduct. Organometallic chemistry and heating are not among the most intuitively sensible combinations. However, prior to the formation of an organometallic species

• oxidations of alcohols to aldehyes or ketones using gold nanoparticles in the presence of oxygen gas or atmospheric air was achieved by modifying the silica shell of nanostructured MagSilicaTM with gold nanoparticles (Scheme 12, case B). After heating these modified SPIONs in an electromagnetic field, a

• continuous process could be established by oxidation with molecular oxygen introduced into the reaction stream via a tube-in-tube membrane reactor, a process which should be very attractive for industrial applications, as oxygen or air act as cheap and environmentally friendly oxidants [82]. An interesting

Rapid gas–liquid reaction in flow. Continuous synthesis and production of cyclohexene oxide

• Kyoko Mandai,
• Tetsuya Yamamoto,
• Hiroki Mandai and
• Aiichiro Nagaki

Beilstein J. Org. Chem. 2022, 18, 660–668, doi:10.3762/bjoc.18.67

• Medical Science, Nijigaoka, Kani-city, Gifu Prefecture, 509-0293, Japan 10.3762/bjoc.18.67 Abstract The enhanced reaction rate in the epoxidation of cyclohexene with air as an oxidant was discovered without any added catalyst utilizing a continuous flow reactor constructed with readily available

• stainless steel parts and devices. This continuous-flow process demonstrates a significant improvement in reaction time for highly selective epoxide production over the batch process due to the efficient mass transfer between the liquid phase and air. The flow process discovered was operated continuously

• with good operational stability, evaluated by a constant high yield of cyclohexene oxide, to obtain the desired product with high productivity. Keywords: air; continuous flow; cyclohexene oxide; flow epoxidation; rapid gas–liquid reaction; Introduction From the past to the present, organic synthesis

Direct C–H amination reactions of arenes with N-hydroxyphthalimides catalyzed by cuprous bromide

• Dongming Zhang,
• Bin Lv,
• Pan Gao,
• Xiaodong Jia and
• Yu Yuan

Beilstein J. Org. Chem. 2022, 18, 647–652, doi:10.3762/bjoc.18.65

• the amidyl radical precursor under air is reported. A possible mechanism is proposed that proceeds via a radical reaction in the presence of CuBr and triethyl phosphite. Keywords: amination; copper; N-hydroxyphthalimides; radical reactions; triethyl phosphite; Introduction Practical methods for

• applied in amination reactions [17][18][19][20][21][22][23][24]. Especially, N-hydroxyphthalimide can react with arenes directly in the presence of palladium [25] or gold [26] (Scheme 1, reactions 1 and 2). Recently, we found that iron catalyzes the amination of arenes with N-hydroxyphthalimide under air

• (reaction 3) [27]. Herein, we report a method for the construction of aromatic amines via the copper-catalyzed intermolecular radical amination of arenes with N-hydroxyphthalimide (NHPI) under air. Results and Discussion Initially, N-hydroxyphthalimide (NHPI, 2a) was reacted with benzene, catalyzed by CuBr

Substituent effect on TADF properties of 2-modified 4,6-bis(3,6-di-tert-butyl-9-carbazolyl)-5-methylpyrimidines

• Irina Fiodorova,
• Tomas Serevičius,
• Rokas Skaisgiris,
• Saulius Juršėnas and
• Sigitas Tumkevicius

Beilstein J. Org. Chem. 2022, 18, 497–507, doi:10.3762/bjoc.18.52

• by a Lambda 950 UV–vis–NIR spectrometer (Perkin Elmer). The fluorescence quantum yields (ΦF) in ambient air were estimated by the integrating sphere method [49] in integrating sphere (Sphere Optics) coupled to a CCD spectrometer PMA-12 (Hamamatsu) via optical fibers excited with a CW xenon lamp. ΦPF

Borylated norbornadiene derivatives: Synthesis and application in Pd-catalyzed Suzuki–Miyaura coupling reactions

• Robin Schulte and
• Heiko Ihmels

Beilstein J. Org. Chem. 2022, 18, 368–373, doi:10.3762/bjoc.18.41

• , the approach presented herein avoids the use of the significantly more expensive reagents such as the arylboronic acid derivatives and the (t-Bu)3P ligand. To add to that, the latter is also highly air sensitive and thus requires special handling, but it is essential for a reasonably efficient Pd

Synthesis of 5-unsubstituted dihydropyrimidinone-4-carboxylates from deep eutectic mixtures

• Sangram Gore,
• Sundarababu Baskaran and
• Burkhard König

Beilstein J. Org. Chem. 2022, 18, 331–336, doi:10.3762/bjoc.18.37

• replacement of organic solvents. The melts are stable against air and have very low vapor pressures resembling the properties of ionic liquids. In addition, the polarity of these melts is very high [33]. Recently, we have explored several organic transformations such as coupling reaction, cycloaddition

Synthesis and late stage modifications of Cyl derivatives

• Phil Servatius and
• Uli Kazmaier

Beilstein J. Org. Chem. 2022, 18, 174–181, doi:10.3762/bjoc.18.19

• , we treated 11 with thioacetic acid and BEt3/air in THF to give 82% of the thiol-ene click product (Scheme 4). Careful analysis of the NMR spectra revealed that the intermediately formed radical cyclized in an intramolecular 5-exo-trig fashion with the internal double bond to form a tetrahydrofuran

1,2-Naphthoquinone-4-sulfonic acid salts in organic synthesis

• Ruan Carlos B. Ribeiro,
• Patricia G. Ferreira,
• Amanda de A. Borges,
• Luana da S. M. Forezi,
• Fernando de Carvalho da Silva and
• Vitor F. Ferreira

Beilstein J. Org. Chem. 2022, 18, 53–69, doi:10.3762/bjoc.18.5

• catecholamines and other compounds, but they can also be ingested as exogenous products of air and water. The most common quinones, such as benzoquinone, naphthoquinone, anthraquinone, and phenanthrenequinone, can be formed by incomplete combustion or photooxidation of their respective polycyclic aromatic

Bifunctional thiourea-catalyzed asymmetric [3 + 2] annulation reactions of 2-isothiocyanato-1-indanones with barbiturate-based olefins

• Jiang-Song Zhai and
• Da-Ming Du

Beilstein J. Org. Chem. 2022, 18, 25–36, doi:10.3762/bjoc.18.3

• organocatalytic domino Michael/cyclization reaction. This annulation reaction can be easily performed under air atmosphere and mild conditions with 5 mol % catalyst loading. By using bifunctional thiourea catalyst, a series of structurally diverse indanone-derived spirobarbiturates could be obtained in high

A two-phase bromination process using tetraalkylammonium hydroxide for the practical synthesis of α-bromolactones from lactones

• Yuki Yamamoto,
• Akihiro Tabuchi,
• Kazumi Hosono,
• Takanori Ochi,
• Kento Yamazaki,
• Shintaro Kodama,
• Akihiro Nomoto and
• Akiya Ogawa

Beilstein J. Org. Chem. 2021, 17, 2906–2914, doi:10.3762/bjoc.17.198

• reaction with bromine (Scheme 1a) [37][38]. While the industrial demand for α-bromolactones has grown in recent years, the above-mentioned laboratory-level synthetic methods are not suitable for scale-up because LDA, TMSCl, and enol silyl ethers are sensitive to moisture and air, as well as being expensive

• –Volhard–Zelinsky-type ring-opening reaction of 1a (Table 1). In this reaction, the corresponding acid bromide is formed in situ by heating with Br2 and a substoichiometric amount of PBr3; the acid bromide is then converted into 2,5-dibromopentanoic acid (2a) via hydrolysis during the workup under open-air

• remove excess amount of Br2 and the formed HBr (under open-air) then filtered. The filtrate was concentrated under reduced pressure to produce 2,5-dibromopentanoic acid 2a in 90% yield with trace amount of 1a. The purity of 2a was determined by 1H and 13C NMR spectroscopy, and 2a was used for the

Effect of a twin-emitter design strategy on a previously reported thermally activated delayed fluorescence organic light-emitting diode

• Ettore Crovini,
• Zhen Zhang,
• Yu Kusakabe,
• Yongxia Ren,
• Yoshimasa Wada,
• Bilal A. Naqvi,
• Prakhar Sahay,
• Tomas Matulaitis,
• Stefan Diesing,
• Ifor D. W. Samuel,
• Wolfgang Brütting,
• Katsuaki Suzuki,
• Hironori Kaji,
• Stefan Bräse and
• Eli Zysman-Colman

Beilstein J. Org. Chem. 2021, 17, 2894–2905, doi:10.3762/bjoc.17.197

• of the light with respect to the plane of the device, total internal reflection at the organic-glass as well as the glass-air interfaces can occur as can coupling to surface plasmon polaritons (SPP) at the interface with the cathode, all contributing to decreasing the external quantum efficiency (EQE