Introducing a new 7-ring fused diindenone-dithieno[3,2-b:2',3'-d]thiophene unit as a promising component for organic semiconductor materials

• Valentin H. K. Fell,
• Joseph Cameron,
• Alexander L. Kanibolotsky,
• Eman J. Hussien and
• Peter J. Skabara

Beilstein J. Org. Chem. 2022, 18, 944–955, doi:10.3762/bjoc.18.94

• Equation 3) [65][66]: In which Eox is the half-wave potential of the first oxidation signal, and Ered is the half-wave potential of the first reduction signal. Ferrocene was used as the internal standard and its HOMO was taken to be −4.8 eV [67]. With these values, the frontier orbital energy levels of EtH

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

• ). When the reaction was stopped after 5 min, only a 26% yield of 3a was obtained (Table 1, entry 2). The use of 1,1'-bis(diphenylphosphino)ferrocene (dppf), which is the optimal ligand under the original conditions for the solution-based protocol [8], provided only trace amounts of 3a (1%, Table 1, entry

Copper-catalyzed monoselective C–H amination of ferrocenes with alkylamines

• Zhen-Sheng Jia,
• Qiang Yue,
• Ya Li,
• Xue-Tao Xu,
• Kun Zhang and
• Bing-Feng Shi

Beilstein J. Org. Chem. 2021, 17, 2488–2495, doi:10.3762/bjoc.17.165

• , including bioactive molecules, were successfully installed to the ortho-position of ferrocene amides with high efficiency under mild conditions. A range of functionalized ferrocenes were compatible to give the aminated products in moderate to good yields. The gram-scale reaction was smoothly conducted and

• the directing group could be removed easily under basic conditions. Keywords: amination; C–H activation; copper; ferrocene; mono-selectivity; Introduction Ferrocene-based compounds have broad applications from asymmetric catalysis to medicinal discovery [1][2][3][4][5][6][7][8]. Therefore, the

• ][10][11][12]. However, the above protocols generally proceeded under harsh conditions that led to poor functional group tolerance and generated stoichiometric amounts of waste. Thus far, the transition-metal-catalyzed C–H functionalization strategy has innovated the way to producing ferrocene

Synthesis and investigation on optical and electrochemical properties of 2,4-diaryl-9-chloro-5,6,7,8-tetrahydroacridines

• Najeh Tka,
• Mohamed Adnene Hadj Ayed,
• Mourad Ben Braiek,
• Mahjoub Jabli and
• Peter Langer

Beilstein J. Org. Chem. 2021, 17, 2450–2461, doi:10.3762/bjoc.17.162

• reference electrode was calibrated using the ferrocene/ferrocenium (Fc/Fc+) redox system [67], the HOMO and LUMO energies were calculated by using the following equations: Here, VFOC is the potential value of Fc/Fc+ under the same experimental conditions (0.52 V) and 4.8 eV is the HOMO energy value of Fc

On the application of 3d metals for C–H activation toward bioactive compounds: The key step for the synthesis of silver bullets

• Renato L. Carvalho,
• Amanda S. de Miranda,
• Mateus P. Nunes,
• Roberto S. Gomes,
• Guilherme A. M. Jardim and
• Eufrânio N. da Silva Júnior

Beilstein J. Org. Chem. 2021, 17, 1849–1938, doi:10.3762/bjoc.17.126

[2 + 1] Cycloaddition reactions of fullerene C₆₀ based on diazo compounds

• Yuliya N. Biglova

Beilstein J. Org. Chem. 2021, 17, 630–670, doi:10.3762/bjoc.17.55

• unusual ferrocene-containing block 202 was synthesized (Scheme 37) [158]. 1-(3-(Benzoyl)propyl)-1-phenyl[6,6]methanofullerene (203) was obtained by 1,3-dipolar cycloaddition of a tosylhydrazone derivative (obtained from 1,3-dibenzoylpropane) to C60 (Scheme 38) [159]. 2-Benzoylpropionic acid was used as

All-carbon [3 + 2] cycloaddition in natural product synthesis

• Zhuo Wang and
• Junyang Liu

Beilstein J. Org. Chem. 2020, 16, 3015–3031, doi:10.3762/bjoc.16.251

• synthesis of longeracinphyllin A (10), which was reported by Li and co-workers in 2017, used a 1,1’-bis(diphenylphosphino)ferrocene-promoted [3 + 2] cycloaddition [44] of enedione 86 and allenoate 87 to give adduct 88 in 45% yield. This adduct 88 was treated with an excess of LiCH2PO(OMe)2 to afford β

• ) were reported by Li’s group [42] and Zhai’s group [43] independently in 2017 (Scheme 6B and Scheme 6C). In Li’s synthesis, the common intermediate dienone 86 was subjected to a 1,1’-bis(diphenylphosphino)ferrocene-promoted [3 + 2] cycloaddition [41] with allenyl ketone 91 to give adduct 92a in 52

Controlled decomposition of SF₆ by electrochemical reduction

• Sébastien Bouvet,
• Bruce Pégot,
• Stéphane Sengmany,
• Erwan Le Gall,
• Eric Léonel,
• Anne-Marie Goncalves and
• Emmanuel Magnier

Beilstein J. Org. Chem. 2020, 16, 2948–2953, doi:10.3762/bjoc.16.244

• . All potentials were measured against a pseudo silver reference electrode (SRE). The addition of ferrocene in the electrolyte gives access to an internal reference [33]. In order to improve the current detection level of SF6, platinum disk electrodes were used as working electrode (Pt

• temperature, under slight argon stream, v = 20 mV/s. (b) Same conditions as for (a) after addition of SF6. (c) Same conditions than (a) after addition of ferrocene (10−3 M). Variation of the current reduction (i2) of SF6 onto Pt macroelectrode (Ø = 0.76 mm) at −2.3 V vs Fc+/Fc in acetonitrile freshly

Ultrasound-assisted Strecker synthesis of novel 2-(hetero)aryl-2-(arylamino)acetonitrile derivatives

• Emese Gal,
• Luiza Gaina,
• Hermina Petkes,
• Alexandra Pop,
• Castelia Cristea,
• Gabriel Barta,
• Dan Cristian Vodnar and
• Luminiţa Silaghi-Dumitrescu

Beilstein J. Org. Chem. 2020, 16, 2929–2936, doi:10.3762/bjoc.16.242

• Abstract This work describes an efficient, simple, and ecofriendly sonochemical procedure for the preparation of new α-(arylamino)acetonitrile derivatives C-substituted with phenothiazine or ferrocene units. The synthetic protocol is based on the Strecker reaction of a (hetero)aryl aldimine substrate with

• that the C-(hetero)aryl-α-(arylamino)acetonitrile derivatives can be considered genotoxically safe and possibly antimutagenic. Keywords: Ames test; α-aminoacetonitriles; ferrocene; phenothiazine; SEM; single crystal XRD; sonochemistry; Introduction Sonochemistry can be considered as a major

• ferrocene unit displays a remarkably reversible one-electron oxidation behavior offering interesting fields of applications for its derivatives as redox mediators in sensor applications [10]. Medicinal applications of ferrocene derivatives grafted on different pharmacophoric units greatly benefit from the

Synthesis and characterization of S,N-heterotetracenes

• Astrid Vogt,
• Florian Henne,
• Christoph Wetzel,
• Elena Mena-Osteritz and
• Peter Bäuerle

Beilstein J. Org. Chem. 2020, 16, 2636–2644, doi:10.3762/bjoc.16.214

• planar and conformationally restricted systems [48]. In order to get information about the redox properties and energetics of the frontier orbitals, the S,N-heteroacenes were studied by cyclic voltammetry and all potentials were referenced against the ferrocene/ferricenium couple (Table 1). In the series

Thermodynamic and electrochemical study of tailor-made crown ethers for redox-switchable (pseudo)rotaxanes

• Henrik Hupatz,
• Marius Gaedke,
• Hendrik V. Schröder,
• Julia Beerhues,
• Arto Valkonen,
• Fabian Klautzsch,
• Sebastian Müller,
• Felix Witte,
• Kari Rissanen,
• Biprajit Sarkar and
• Christoph A. Schalley

Beilstein J. Org. Chem. 2020, 16, 2576–2588, doi:10.3762/bjoc.16.209

• ferrocene [14][17]. Yet, switchable crown ethers are also widely applied as cation sensors, where the sensor activity can be controlled by external stimuli, e.g., light, the redox potential or chemical reagents [14][17]. Redox-switchable crown ethers have been shown to sense cations by the generation of an

Synthetic approaches to bowl-shaped π-conjugated sumanene and its congeners

• Shakeel Alvi and
• Rashid Ali

Beilstein J. Org. Chem. 2020, 16, 2212–2259, doi:10.3762/bjoc.16.186

• by virtue of ROM–RCM which on subsequent DDQ oxidation followed by HWE reaction provided the desired compound 108 (Scheme 26). In a really brilliant manner, Kasprzak and Sakurai in 2019 have created a sumanene–ferrocene dual system for selective recognition of cesium cations by means of site

• ferrocene–sumanene conjugates by employing reductive amination reaction for the formation of compounds 110 and 116. Whereas compounds 111, 113, and 117 were prepared by means of condensation reaction as depicted in Scheme 27. On the other hand, Lentz’s group has reported the synthesis of sumanenylferrocene

• 118 as well as 1,1’-disumanenylferrocene 119 through Pd-catalyzed Negishi coupling of iodosumanene (79) with ferrocenylzinc chloride and 1,1’-bis(chlorozincio)ferrocene (Scheme 28) [9]. These synthesized molecules were confirmed utilizing spectroscopic techniques as well as by virtue of X-ray

Models of necessity

• Timothy Clark and
• Martin G. Hicks

Beilstein J. Org. Chem. 2020, 16, 1649–1661, doi:10.3762/bjoc.16.137

• chemist who uses predominantly the Lewis bonding picture or an inorganic chemist rooted in the VSEPR model switch quite happily to qualitative molecular-orbital arguments to explain electrocyclic reactions or the structure of ferrocene, even in teaching. In contrast, cheminformatics will need to adopt a

Five-component, one-pot synthesis of an electroactive rotaxane comprising a bisferrocene macrocycle

• Natalie Lagesse,
• Luca Pisciottani,
• Maxime Douarre,
• Pascale Godard,
• Brice Kauffmann,
• Vicente Martí-Centelles and
• Nathan D. McClenaghan

Beilstein J. Org. Chem. 2020, 16, 1564–1571, doi:10.3762/bjoc.16.128

• of Bordeaux, Pessac, France 10.3762/bjoc.16.128 Abstract The templated clipping of a ferrocene-grafted isophthalic acid derivative to encircle a hydrogen-bonding axle through the reaction with 1,4-bis(aminomethyl)benzene is described. The constituent electroactive macrocycle of the resultant [2

• crystal X-ray structure of a doubly ferrocene-decorated [2]rotaxane are further reported. Keywords: ferrocene; macrocycle; rotaxane; single crystal X-ray structure; template; Introduction The development of interlocked molecules with tailored properties allowed the preparation of molecular machines able

• ][10][11][12][13][14]. In this context, we report the synthesis of a rotaxane, where a “clipping” reaction generates a tetraamide macrocycle with two peripheral ferrocene moieties on a preformed thread (Figure 1b). The resulting versatile and easily accessible electroactive macrocycle is anticipated to

Ferrocenyl-substituted tetrahydrothiophenes via formal [3 + 2]-cycloaddition reactions of ferrocenyl thioketones with donor–acceptor cyclopropanes

• Grzegorz Mlostoń,
• Mateusz Kowalczyk,
• André U. Augustin,
• Peter G. Jones and
• Daniel B. Werz

Beilstein J. Org. Chem. 2020, 16, 1288–1295, doi:10.3762/bjoc.16.109

• used with no special precautions. In general, ferrocene has been considered as an ‘exceptional compound’ [16][17] and in our hands ferrocenyl-functionalized sulfur heterocycles, e.g., thiiranes and 1,3-dithiolanes, have found applications for the synthesis of compounds relevant for medicinal [18] and

• sides of the ring plane. The described reactions supplement the recently reported synthetic applications of alkyl/ferrocenyl thioketones as attractive substrates for the synthesis of chiral ferrocene derivatives [22] and ferrocenyl-substituted platinathiiranes [23]. It should be also emphasized that the

Synthesis and properties of quinazoline-based versatile exciplex-forming compounds

• Rasa Keruckiene,
• Simona Vekteryte,
• Ervinas Urbonas,
• Matas Guzauskas,
• Eigirdas Skuodis,
• Dmytro Volyniuk and
• Juozas V. Grazulevicius

Beilstein J. Org. Chem. 2020, 16, 1142–1153, doi:10.3762/bjoc.16.101

• summarized in Table 1. The ionization potential (IPCV) and electron affinity (EACV) values were estimated accordingly from the oxidation and reduction onset potentials against ferrocene (Eox/Ered,onset vs Fc). The IPCV values demonstrated the similar and collaborative electron-donating effect of the

• . The potentials were calibrated against the standard ferrocene/ferrocenium (Fc/Fc+) redox system [24]. The ground-state geometries were optimized by using the B3LYP (Becke three parameters hybrid functional with Lee–Yang–Perdew correlation) [25] functional at the 6-31G (d, p) level of theory in vacuum

Synthesis of novel multifunctional carbazole-based molecules and their thermal, electrochemical and optical properties

• Nuray Altinolcek,
• Ahmet Battal,
• Mustafa Tavasli,
• William J. Peveler,
• Holly A. Yu and
• Peter J. Skabara

Beilstein J. Org. Chem. 2020, 16, 1066–1074, doi:10.3762/bjoc.16.93

• tetrabutylammonium hexafluorophosphate as the electrolyte (Figure 2). A platinum disk was used as a working electrode, silver wire as the reference electrode and platinum wire as the counter electrode. The ferrocene-ferrocenium redox couple was used as an internal reference. At positive potentials, compounds 7a and

• molecular orbital and the lowest unoccupied molecular orbital energy levels (EHOMO, ELUMO) of compounds 7a and 7b were also calculated from the half-way anodic oxidation and onset cathodic reduction peak potentials, with respect to the energy level of ferrocene (4.8 eV below vacuum level) [38] by using the

Fluorinated phenylalanines: synthesis and pharmaceutical applications

• Laila F. Awad and
• Mohammed Salah Ayoup

Beilstein J. Org. Chem. 2020, 16, 1022–1050, doi:10.3762/bjoc.16.91

• -catalyzed asymmetric hydrogenation of the α-amidocinnamic acid 63 using the less frequently used ferrocene-based ligand Me-BoPhoz led to the N-acetyl-ʟ-phenylalanine derivative 64 with complete conversion and with 94% ee. The desired enantiomer (S)-65 was obtained as a single isomer (>99% ee) after

Suzuki–Miyaura cross coupling is not an informative reaction to demonstrate the performance of new solvents

• James Sherwood

Beilstein J. Org. Chem. 2020, 16, 1001–1005, doi:10.3762/bjoc.16.89

• observed throughout unless noted subsequently. The first case study was adapted from that developed by Watson and co-workers [3][6]. The desired coupling is of 4-bromotoluene to produce 4-phenyltoluene, assisted by the inclusion of the bis(diphenylphosphino)ferrocene ligand and 3 equivalents of base

Visible-light-induced addition of carboxymethanide to styrene from monochloroacetic acid

• Kaj M. van Vliet,
• Nicole S. van Leeuwen,
• Albert M. Brouwer and
• Bas de Bruin

Beilstein J. Org. Chem. 2020, 16, 398–408, doi:10.3762/bjoc.16.38

• ferrocene with 0.1 M [TBA][PF6] in MeCN. The potential is referenced to the Fc/Fc+ redox couple (0 V). The excited state reduction potentials of two different reducing photoredox catalysts (in red and green) are shown in the figure. EPR spectra measured (black) and simulated (red) based on the structure of

Architecture and synthesis of P,N-heterocyclic phosphine ligands

• Wisdom A. Munzeiwa,
• Bernard Omondi and
• Vincent O. Nyamori

Beilstein J. Org. Chem. 2020, 16, 362–383, doi:10.3762/bjoc.16.35

• 57. Coupling of 57 with Ph2PCl·BH3 resulted in the boron-protected ligand 58, which was deprotected with Et3N. Alternatively, 1,1’-bis(diphenylphosphino)ferrocene (dppf) with palladium(II) acetate was used to catalyze the reduction of 55 generating the pyridine scaffold 57. Subsequent lithiation and

• ][112]. Phosphines with amine functional groups can easily undergo Mannich condensation reactions. Ferrocene-based Schiff base ligands containing pyridine-n-yl ring (n = 2, 3, 4) (Scheme 27) were synthesized by Hu et al. [113] through the Mannich condensation of ferrocenylphosphine amine 142 and the

• a Zn-oxazole complex 148. Finally, ligand exchange with 2,2-bipyridine generated the desired 2-(diphenylphosphine)oxazole 149. Metallocenes have been used as ligand building blocks for many catalytic transformations. Especially, ferrocene has been used due to its high electron-donating capability

Copper-promoted/copper-catalyzed trifluoromethylselenolation reactions

• Clément Ghiazza and
• Anis Tlili

Beilstein J. Org. Chem. 2020, 16, 305–316, doi:10.3762/bjoc.16.30

• and molecular oxygen as the oxidant, the substrates were successfully converted to the trifluoromethylselenylated analogs in good to very good yields. The substrate scope highlighted a broad functional group tolerance, including electron-withdrawing and -donating groups, heterocycles, and ferrocene

A new approach to silicon rhodamines by Suzuki–Miyaura coupling – scope and limitations

• Thines Kanagasundaram,
• Antje Timmermann,
• Carsten S. Kramer and
• Klaus Kopka

Beilstein J. Org. Chem. 2019, 15, 2569–2576, doi:10.3762/bjoc.15.250

• '-bis(diphenylphosphino)ferrocene). Remarkably, not only the yield was increased with PdCl2(dppf) from 49% to 67%, even the dye 22 was obtained with high purity after column chromatography without the necessity of further HPLC purification (Table 1, entry 8). Exploration of substrate scope Next we

Formation of alkyne-bridged ferrocenophanes using ring-closing alkyne metathesis on 1,1’-diacetylenic ferrocenes

• Celine Bittner,
• Dirk Bockfeld and
• Matthias Tamm

Beilstein J. Org. Chem. 2019, 15, 2534–2543, doi:10.3762/bjoc.15.246

• isolated from THF solution. Keywords: alkyne metathesis; ferrocene; homogeneous catalysis; molybdenum; terminal alkynes; Introduction Alkyne metathesis, the reversible making and breaking of carbon–carbon triple bonds, is clearly gaining more attention. Not only could a great number of active catalysts

• illustrated for alkyne metathesis reactions of organometallic compounds. After some stoichiometric reactions of ruthenium and rhenium half sandwich complexes [70], several reactions have been described exploiting the reactivity of acetylenic ferrocene compounds [71][72][73][74][75]. For most of these

• conversions the Mortreux catalyst system Mo(CO)6/ArOH was used at elevated temperatures. Because of the electronic properties of the ferrocene unit, polymers of acetylenic ferrocenes can be used for example as molecular wires [75]. Coming to ferrocenophanes, mainly carbon-bridged compounds are known [76][77

Experimental and computational electrochemistry of quinazolinespirohexadienone molecular switches – differential electrochromic vs photochromic behavior

• Eric W. Webb,
• Jonathan P. Moerdyk,
• Kyndra B. Sluiter,
• Benjamin J. Pollock,
• Amy L. Speelman,
• Eugene J. Lynch,
• William F. Polik and
• Jason G. Gillmore

Beilstein J. Org. Chem. 2019, 15, 2473–2485, doi:10.3762/bjoc.15.240

• nitrogen-purged MBraun MBS-SPS 07-299 solvent purification system) or highest anhydrous grade (used as received). Acetonitrile-d3 and acetone-d6 were used as received in 1 g ampules (Cambridge Isotope Labs). Ferrocene, tetrabutylammonioum hexafluorophosphate (TBAH), and silver nitrate were of

• through a Teflon cell cap. Rather than relying on either the Ag/AgNO3 reference or Ag wire pseudo-reference, the voltammetry was corrected to a ferrocene external reference. Ferrocene solutions were cyclically scanned before and after each analyte experiment, beginning in the positive (oxidative

• oxidation–reduction of ferrocene had a peak separation of ca. 60 mV and good peak shape without entering oscillation. Typical iR compensation in acetonitrile ranged from 150–230 Ω. Photochromic solutions were cyclically scanned beginning in the negative (reductive) direction at 0.1–0.5 V/s with 1 mV sample