Preparing a liquid crystalline dispersion of carbon nanotubes with high aspect ratio

• Keiko Kojima,
• Nodoka Kosugi,
• Hirokuni Jintoku,
• Kazufumi Kobashi and
• Toshiya Okazaki

Beilstein J. Org. Chem. 2024, 20, 52–58, doi:10.3762/bjoc.20.7

• acetone using a bath-type sonicator and were put onto a copper grid with carbon mesh. To perform thermogravimetric analysis (TGA), a TG/DTA7300 instrument from SII Nano Technology Inc. was utilized. The DWCNT powder was preheated at 180 °C for ten minutes under vacuum and subsequently measured under

Synthesis of N-acyl carbazoles, phenoxazines and acridines from cyclic diaryliodonium salts

• Nils Clamor,
• Mattis Damrath,
• Thomas J. Kuczmera,
• Daniel Duvinage and
• Boris J. Nachtsheim

Beilstein J. Org. Chem. 2024, 20, 12–16, doi:10.3762/bjoc.20.2

• Bremen, Germany 10.3762/bjoc.20.2 Abstract N-Acyl carbazoles can be efficiently produced through a single-step process using amides and cyclic diaryliodonium triflates. This convenient reaction is facilitated by copper iodide in p-xylene, using the commonly found activating ligand diglyme. We have

Aldiminium and 1,2,3-triazolium dithiocarboxylate zwitterions derived from cyclic (alkyl)(amino) and mesoionic carbenes

• Nedra Touj,
• François Mazars,
• Guillermo Zaragoza and
• Lionel Delaude

Beilstein J. Org. Chem. 2023, 19, 1947–1956, doi:10.3762/bjoc.19.145

• -disubstituted-1,2,3-triazole derivatives is readily achieved via the copper(I)-catalyzed [3 + 2] cycloaddition of an azide and a terminal alkyne (CuAAC) [63][64][65]. A further alkylation of the N3 position with an alkyl halide is an equally straightforward procedure that ultimately affords a large assortment

• ). The active catalytic species for the CuAAC reaction were generated by reducing copper(II) sulfate with sodium ascorbate according to literature procedures [66][67]. 2-Azido-1,3,5-trimethylbenzene (mesityl azide) was easily synthesized in a distinct, preliminary step through the Sandmeyer reaction of

Aromatic systems with two and three pyridine-2,6-dicarbazolyl-3,5-dicarbonitrile fragments as electron-transporting organic semiconductors exhibiting long-lived emissions

• Karolis Leitonas,
• Brigita Vigante,
• Dmytro Volyniuk,
• Audrius Bucinskas,
• Pavels Dimitrijevs,
• Sindija Lapcinska,
• Pavel Arsenyan and
• Juozas Vidas Grazulevicius

Beilstein J. Org. Chem. 2023, 19, 1867–1880, doi:10.3762/bjoc.19.139

• copper(I) iodide in DMF/DIPEA solution at 55 °C with subsequent desilylation with potassium carbonate. Finally, butadiyne 6 was prepared by a homocoupling reaction of 5 with 80% yield. Derivatives containing two dicyanopyridyl moieties, 7 and 8, were prepared starting with a Sonogashira coupling of

Recent advancements in iodide/phosphine-mediated photoredox radical reactions

• Tinglan Liu,
• Yu Zhou,
• Junhong Tang and
• Chengming Wang

Beilstein J. Org. Chem. 2023, 19, 1785–1803, doi:10.3762/bjoc.19.131

• transformations, as depicted in Scheme 14. The dual-catalytic cycle comprised a photocatalytic cycle and a copper catalytic cycle, interconnected through an intermolecular single-electron transfer. Within the context of the photocatalytic cycle, the generation of the C(sp3)-centered alkyl radical A was

• facilitated by the process of photoexcited radical decarboxylation. On the other hand, the copper catalytic cycle involved the capture of alkyl radicals by the copper complex B, the activation of heteroatom-containing substrates 30 by a base-mediated proton transfer, and the subsequent reductive elimination

Active-metal template clipping synthesis of novel [2]rotaxanes

• Cătălin C. Anghel,
• Teodor A. Cucuiet,
• Niculina D. Hădade and
• Ion Grosu

Beilstein J. Org. Chem. 2023, 19, 1776–1784, doi:10.3762/bjoc.19.130

• of the final [2]rotaxanes by active template copper(I)-catalyzed alkyne–azide cycloaddition (CuAAC) as key step of the synthesis. HRMS and NMR experiments have been performed to confirm the formation of the interlocked structures. Keywords: active-metal template; clipping; copper(I)-catalyzed alkyne

• molecule which catalyzes the macrocyclization reaction around the axle (Figure 1b). Results and Discussion In order to access the target [2]rotaxanes we made use of the CuAAC reaction, performed in the presence of a copper(I) N-heterocyclic carbene, a very stable and efficient class of catalysts used in

• obtained by CuAAC in the presence of CuCl(SIMes)(4,7-diclorophenantroline) as catalyst, with very good yields. Next, we set to study the ability of compound 6 to form copper(I) complexes able to act as active-metal templates for [2]rotaxane synthesis. Therefore, complexation studies of 6 with CuCl(SIMes

Selectivity control towards CO versus H₂ for photo-driven CO₂ reduction with a novel Co(II) catalyst

• Lisa-Lou Gracia,
• Philip Henkel,
• Olaf Fuhr and
• Claudia Bizzarri

Beilstein J. Org. Chem. 2023, 19, 1766–1775, doi:10.3762/bjoc.19.129

• selectivity from 6% to 97% after four hours of irradiation at 420 nm. Further efficiency enhancement was achieved by adding 1,1,1,3,3,3-hexafluoropropan-2-ol, producing CO with a TON up to 230, although at the expense of selectivity (54%). Keywords: carbon monoxide selectivity; cobalt(II) complex; copper(I

• complex obtainable via a straightforward synthesis, with improved solubility, concerning our previous Co(II) complexes [21]. Thus, the new Co(II) complex bears two 1-benzyl-4-(quinolin-2-yl)-1H-1,2,3-triazole (BzQuTr) units, that were obtained through a copper-catalyzed alkyne–azide cycloaddition (CuAAC

Effects of the aldehyde-derived ring substituent on the properties of two new bioinspired trimethoxybenzoylhydrazones: methyl vs nitro groups

• Dayanne Martins,
• Roberta Lamosa,
• Talis Uelisson da Silva,
• Carolina B. P. Ligiero,
• Sérgio de Paula Machado,
• Daphne S. Cukierman and
• Nicolás A. Rey

Beilstein J. Org. Chem. 2023, 19, 1713–1727, doi:10.3762/bjoc.19.125

• ][35][36]. Our lead compound INHHQ (or 8-hydroxyquinoline-2-carboxaldehyde isonicotinoyl hydrazone) has been successfully tested in the prevention of short- and long-term memory deficits in a mice model of sporadic AD [33]. Additionally, INHHQ decreases copper-mediated production of reactive oxygen

• proved the promising anti-PD and metallophoric effect, especially towards intracellularly relevant copper(I) ions, of X1INH (1-methyl-1H-imidazole-2-carboxaldehyde isonicotinoyl hydrazone) [32]. This year, we evaluated the effects of the presence of three methoxy substituents in an N-acylhydrazone

• affect its pharmacological properties and metallophoric potential against copper(II) when compared to the unsubstituted counterpart. Nevertheless, the bioinspired compound was still able to reduce oxidative stress and affect the aggregation of the amyloid-β peptide, related to pathophysiological events

Tying a knot between crown ethers and porphyrins

• Maksym Matviyishyn and
• Bartosz Szyszko

Beilstein J. Org. Chem. 2023, 19, 1630–1650, doi:10.3762/bjoc.19.120

• of coordination compounds of copper(II), iron(II/III), manganese(II), nickel(II), and cobalt(II) with 9-Zn and 9-Cu was demonstrated. The emission quenching was rationalised considering the binding of the transition metal within the crown ether cavity. No quenching was observed upon the addition of

• porphyrins was investigated, resulting in the formation of lead(II), zinc(II), and copper(II) binuclear coordination compounds [54]. The synthetic methodology developed by Sessler allowed to generate a variety of expanded Schiff porphyrinoids [30][128] and texaphyrins [57][60][129]. The group has also

• the aryl group at the meso-position of the dipyrrin moiety. Compound 40 was tested for sensing metal ions, and while no significant changes were observed with most cations, the addition of Cu(II) resulted in a colour change. UV–vis spectroscopy and mass spectrometry confirmed the 1:1 copper(II

Lewis acid-promoted direct synthesis of isoxazole derivatives

• Dengxu Qiu,
• Chenhui Jiang,
• Pan Gao and
• Yu Yuan

Beilstein J. Org. Chem. 2023, 19, 1562–1567, doi:10.3762/bjoc.19.113

• reported [16]. In 2015, Yang’s group [10][17] reported the copper-catalyzed conversion of methylarenes into isoxazole derivatives with KNO3 as the source of nitrile oxide (Scheme 1, reaction 1). In 2019, Deng’s group [18] developed a three-component synthesis method of isoxazole derivatives using TBN as

• nitrogen source (Scheme 1, reaction 2). In 2017, Xu and co-workers [19] developed a copper-mediated annulation reaction to synthesize isoxazoles from two different alkynes. In fact, most methods mostly used highly toxic transition-metal catalysts such as copper metals. In order to develop cheaper and more

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

• decomposition of azides at higher temperatures required the use of 2a or 2b in excess. No significant difference in yields between 1.5 equiv and 2 equiv of the aryl azide was observed. Adding fluorophilic additives (TMSCl, Table 1, entry 5) or using copper as other transition metal (CuCl or Cu(OAc)2, Table 1

• did not improve the yields when a cyano group was present on the azide handle. In fact, the use of CuSO4 with the cyano group lowered the yield (31%, see entry 12 in Table 1) which might be due to a coordination of the copper catalyst with the cyano group hindering the triazole formation [37]. The

Synthesis and biological evaluation of Argemone mexicana-inspired antimicrobials

• Jessica Villegas,
• Bryce C. Ball,
• Katelyn M. Shouse,
• Caleb W. VanArragon,
• Ashley N. Wasserman,
• Hannah E. Bhakta,
• Allen G. Oliver,
• Danielle A. Orozco-Nunnelly and
• Jeffrey M. Pruet

Beilstein J. Org. Chem. 2023, 19, 1511–1524, doi:10.3762/bjoc.19.108

• most streamlined method involves a copper-promoted Pictet–Spengler-type cyclization with glyoxal, with oxidative aromatization at the 8-position (Scheme 1) [30][35]. A recent report suggested a mechanistic role of Cu2+ involving C–H activation [36]; however, it is known that this reaction proceeds

• smoothly to the dihydroberberine in the absence of the copper salt [37]. This suggests the Cu2+ may be involved in aiding in the air-oxidation to the fully aromatic berberine core. The prime benefit of the route shown in Scheme 1 is the ease of introducing structural variability, as the precursor is easily

N-Sulfenylsuccinimide/phthalimide: an alternative sulfenylating reagent in organic transformations

• Fatemeh Doraghi,
• Seyedeh Pegah Aledavoud,
• Mehdi Ghanbarlou,
• Bagher Larijani and
• Mohammad Mahdavi

Beilstein J. Org. Chem. 2023, 19, 1471–1502, doi:10.3762/bjoc.19.106

• the presence of N-(2-bromophenylthio)succinimide 1’ and copper catalyst led to intermolecular sulfenoamination of alkenes and subsequent C–N coupling to produce dihydrobenzothiazine structures 27 in a one-pot manner. Furthermore, deprotection of the amine unit by K2CO3 and Na metal was performed in

• as a sulfenylating source gave the target product in 93% yield. Knochel and co-workers found that copper acetate can catalyze the cross-coupling reaction between (hetero)aryl, alkyl and benzylic zinc halides 36 with N-thiophthalimides 14 (Scheme 18) [55]. Various metal catalysts, including CrCl2

• , CoCl2, NiCl2, MnCl2, FeCl2, Fe(acac)3 and copper salts such as Cu(OAc)2, CuBr2, CuBr, CuCl2, and CuCN·2LiCl were evaluated in this coupling reaction, in which Cu(OAc)2 showed highest product yields. Moreover, phthalimides with SCF3, SCN, and SePh groups also worked well in this approach. Because of the

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

• and copper salts in the presence of NaOt-Bu in THF [15]. All attempts to prepare the corresponding iodide-containing compounds resulted in the formation of [(NHC)2Cu]+ species [15]. The copper complexes bearing ICy and It-Bu ligands were found to be sensitive to the excess of base and hence could not

• , K2CO3, or Cs2CO3) in the presence of copper chlorides (Scheme 11). However, this protocol required environmental unfriendly solvents such as 3-chloropyridine and high temperatures. In general, CuCl gave higher yields than CuCl2·2H2O typically ranging from 70 to 99% [24]. Furthermore, an IMes–CuCl

• diaminocarbene complex 32 and diamidocarbene (DAC) complex 33. The mononuclear N-heterocyclic carbene (NHC)–copper alkoxide complexes [(6-NHC)CuOt-Bu] (6-NHC = 6-MesDAC (30), 6-Mes (31)) were prepared by the addition of free carbenes to the tetrameric tert-butoxide precursor [Cu(Ot-Bu)]4, or by protonolysis of

One-pot nucleophilic substitution–double click reactions of biazides leading to functionalized bis(1,2,3-triazole) derivatives

• Hans-Ulrich Reissig and
• Fei Yu

Beilstein J. Org. Chem. 2023, 19, 1399–1407, doi:10.3762/bjoc.19.101

• azide was combined with a subsequent copper-catalyzed (3 + 2) cycloaddition with terminal alkynes. This one-pot process was developed with a simple model alkyne, but then applied to more complex alkynes bearing enantiopure 1,2-oxazinyl substituents. Hence, the precursor compounds 1,2-, 1,3- or 1,4-bis

• carbohydrate mimetics, but the reductive cleavage of the 1,2-oxazine rings to aminopyran moieties did not proceed cleanly with these compounds. Keywords: alkynes; azides; copper catalysis; nucleophilic substitution; 1,2-oxazines; Introduction The concept of click reactions [1][2], in particular, the

• discovery of the copper-catalyzed alkyne azide (3 + 2) cycloaddition (CuAAC) [3][4], has dramatically changed the approaches to many problems in chemistry, supramolecular chemistry, materials science, biological chemistry and related fields (selected reviews: [5][6][7][8][9][10][11][12][13][14][15

Consecutive four-component synthesis of trisubstituted 3-iodoindoles by an alkynylation–cyclization–iodination–alkylation sequence

• Nadia Ledermann,
• Alae-Eddine Moubsit and
• Thomas J. J. Müller

Beilstein J. Org. Chem. 2023, 19, 1379–1385, doi:10.3762/bjoc.19.99

• generated by a consecutive four-component reaction starting from ortho-haloanilines, terminal alkynes, N-iodosuccinimide, and alkyl halides in yields of 11–69%. Initiated by a copper-free alkynylation, followed by a base-catalyzed cyclizive indole formation, electrophilic iodination, and finally

• Discussion In our previous studies on the alkynylation–cyclization synthesis of 2-substituted (aza)indoles [32][33][34], we could show that the copper-free Pd-catalyzed alkynylation of 2-aminobromopyridines or 2-bromoanilines and the subsequent base-catalyzed anellation in a one-pot fashion proceeds without

• commences with a copper-free alkynylation using DBU as a base at 100 °C. This step is followed by the addition of KOt-Bu and reaction at 100 °C for 15 min and subsequent reaction with N-iodosuccinimide (3) at room temperature. Finally, the reaction with alkyl halides 4 at room temperature gives the title

Synthesis of ether lipids: natural compounds and analogues

• Marco Antônio G. B. Gomes,
• Alicia Bauduin,
• Chloé Le Roux,
• Romain Fouinneteau,
• Wilfried Berthe,
• Mathieu Berchel,
• Hélène Couthon and
• Paul-Alain Jaffrès

Beilstein J. Org. Chem. 2023, 19, 1299–1369, doi:10.3762/bjoc.19.96

• - or 3-bromoanisole were also reported) with bromotetradecane in the presence of a copper salt (Figure 10). Then, the deprotection of the phenol function with BBr3 produced 10.2. The deprotonation of the phenol function with NaH in DMF and its reaction with solketal mesylate produced, after the

Non-noble metal-catalyzed cross-dehydrogenation coupling (CDC) involving ether α-C(sp³)–H to construct C–C bonds

• Hui Yu and
• Feng Xu

Beilstein J. Org. Chem. 2023, 19, 1259–1288, doi:10.3762/bjoc.19.94

• . Route b: the α-C(sp3)–H bonds are activated by a combination of transition metals and radical initiators to give the alkyl radicals, which are coupled with other radical receptors to afford the target product. Cu-catalyzed reactions Copper (common oxidation states are +I, +II and +III) has a

• significantly different reactivity and chemical selectivity from noble metals (Ru, Rh, Pd). Compared with noble metals, copper catalysts are cheaper and easier to obtain, making Cu more advantageous for industrial applications of C–H functionalization reactions. The Glaser–Hay reaction may be one of the oldest

• reactions. Although the range of substrates for different C–H nucleophiles remains restricted, in recent years, copper-catalyzed oxidative coupling reactions between different C–H nucleophiles have been established. There are several common valence changes of copper in the catalytic process [44][45][46][47

Radical ligand transfer: a general strategy for radical functionalization

• David T. Nemoto Jr,
• Kang-Jie Bian,
• Shih-Chieh Kao and
• Julian G. West

Beilstein J. Org. Chem. 2023, 19, 1225–1233, doi:10.3762/bjoc.19.90

• form new C–Cl bonds in the presence of transient alkyl radicals, with mechanistic studies implicating homolytic abstraction of a chlorine ligand from the intermediate copper complex. Outside of the substitution products which could be generated from the RLT pathway, alkyl radicals could also undergo an

• elimination-like pathway to afford unsaturated C–C bonds in the presence of copper(II) sulfate, presumably via competitive RPC to the carbocation followed by E1 olefination. Kochi also demonstrated that RLT can be combined with other radical generation strategies to enable new, non-biomimetic reactions to be

• charge transfer (LMCT) which, following cage escape, could add to the alkene to generate an alkyl radical. This alkyl radical could then be chlorinated via RLT from a second Cu(II) chloride species, furnishing the dichlorinated product. While copper was unable to be used catalytically in this early

Unravelling a trichloroacetic acid-catalyzed cascade access to benzo[f]chromeno[2,3-h]quinoxalinoporphyrins

• Chandra Sekhar Tekuri,
• Pargat Singh and
• Mahendra Nath

Beilstein J. Org. Chem. 2023, 19, 1216–1224, doi:10.3762/bjoc.19.89

• Chandra Sekhar Tekuri Pargat Singh Mahendra Nath Department of Chemistry, Faculty of Science, University of Delhi, Delhi 110 007, India 10.3762/bjoc.19.89 Abstract A facile one-pot four-component synthetic methodology is evolved to construct novel copper(II) benzo[f]chromeno[2,3-h

• ]quinoxalinoporphyrins in good yields via a sequential reaction of copper(II) 2,3-diamino-5,10,15,20-tetraarylporphyrins, 2-hydroxynaphthalene-1,4-dione, aromatic aldehydes, and dimedone in the presence of a catalytic amount of trichloroacetic acid in chloroform at 65 °C. Further, the newly prepared copper(II

• present study discloses an easy and first synthetic approach to build highly π-conjugated copper(II) benzo[f]chromeno[2,3-h]quinoxalinoporphyrins through a trichloroacetic acid-catalyzed one-pot four-component reaction of 2,3-diamino-5,10,15,20-tetraarylporphyrins, 2-hydroxynaphthalene-1,4-dione, aromatic

Enabling artificial photosynthesis systems with molecular recycling: A review of photo- and electrochemical methods for regenerating organic sacrificial electron donors

• Grace A. Lowe

Beilstein J. Org. Chem. 2023, 19, 1198–1215, doi:10.3762/bjoc.19.88

• in acetonitrile with proton donors [45]. They carefully calculated the pKaH of their proton donors and NADH analogues to control the PCET and to prevent side reactions. In another interesting example, NADH was recycled at a copper electrode in aqueous buffers and NADH was found to be more stable in a

Exploring the role of halogen bonding in iodonium ylides: insights into unexpected reactivity and reaction control

• Carlee A. Montgomery and
• Graham K. Murphy

Beilstein J. Org. Chem. 2023, 19, 1171–1190, doi:10.3762/bjoc.19.86

• have been feasible. In 1989, Moriarty was investigating the intramolecular cyclopropanation of 10 under copper-catalysis, presuming that the reaction would proceed through a metallocarbene intermediate [113]. However, a control experiment showed the reaction to also be viable without catalyst, from

• their rhodium- and copper-catalyzed reactions (Scheme 2c) [116]. These results were in stark contrast to those observed for the ylide’s diazo counterparts, which did not react without a catalyst, and which gave the opposite diastereoselectivity with copper and rhodium. Inspired by ionic pathways

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

Copper-catalyzed N-arylation of amines with aryliodonium ylides in water

• Kasturi U. Nabar,
• Bhalchandra M. Bhanage and
• Sudam G. Dawande

Beilstein J. Org. Chem. 2023, 19, 1008–1014, doi:10.3762/bjoc.19.76

• .19.76 Abstract Copper sulfate catalyzed an efficient, inexpensive, and environment-friendly protocol that has been developed for N-arylation of amines with 1,3-cyclohexadione-derived aryliodonium ylides in water as a green solvent. Aromatic primary amines substituted with electron-donating as well as

• bond formation. However, these methods suffer from limitations such as moisture sensitivity, the requirement of specific ligands, and the use of expensive palladium catalysts [17]. Also, Chan Lam, Evans, and other research groups have developed copper-catalyzed C–N bond formation reactions by careful

• tuning of the ligand and base combinations [18][19]. Thereafter, copper-catalyzed C–N bond-formation reactions have experienced unprecedented development due to mild reaction conditions and the low cost of copper salts [20][21][22]. On the other hand, hypervalent iodine reagents serve as versatile tools

Clauson–Kaas pyrrole synthesis using diverse catalysts: a transition from conventional to greener approach

• Dileep Kumar Singh and
• Rajesh Kumar

Beilstein J. Org. Chem. 2023, 19, 928–955, doi:10.3762/bjoc.19.71

• at 60 °C (Scheme 15). Among the different solvents used to optimize the reaction conditions, H2O turned out to be a better and greener solvent compared to other organic solvents (e.g., MeCN, C6H6, CH2Cl2, THF, EtOH, EtOAc). Deng et al. [69] brilliantly described an expedient copper-catalyzed Clauson

• synthesis and proposed mechanism of N-substituted pyrroles 29. Magnetic nanoparticle-supported antimony catalyst used in the synthesis of N-substituted pyrroles 31. Iron(III) chloride-catalyzed synthesis of N-substituted pyrroles 33. Copper-catalyzed Clauson–Kaas synthesis and mechanism of pyrroles 35. β-CD

• -SO3H-catalyzed synthesis and proposed mechanism of pyrroles 37. Solvent-free and catalyst-free synthesis and plausible mechanism of N-substituted pyrroles 39. Nano-sulfated TiO2-catalyzed synthesis of N-substituted pyrroles 41. Copper nitrate-catalyzed Clauson–Kaas synthesis and mechanism of N