- 1,2-DISUBSTITUIERTE FERROCENE VIA 2-FERROCENYL-2-OXAZOLINE
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2-Ferrocenyl-2-oxazolines, available from the reaction of chlorocarbonylferrocene with aziridines and subsequent acid-catalyzed isomerisation, are metallated (lithiated) regiospecifically in the 2-position of the ferrocenyl moiety.Further reaction of the metallated compounds with electrophiles gives 1,2-disubstituted ferrocenes solely.In contrast to the analogous 2-phenyl-2-oxazolines, 2-ferrocenyl-2-oxazolines exhibit high stability under acid-catalyzed solvolytic attack conditions.The reason for this unexpected behaviour is discussed.
- Schmitt, Guenter,Klein, Peter,Ebertz, Wolfgang
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- Asymmetric synthesis of planar chiral ferrocenes by enantioselective intramolecular C-H arylation of N-(2-haloaryl)ferrocenecarboxamides
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The palladium-catalyzed intramolecular C-H arylation reaction of N-(2-bromoaryl)ferrocenecarboxamides furnishes planar chiral ferrocene derivatives. TADDOL-derived phosphoramide ligands induce enantioselectivities ranging from 91:9 to 98:2 er. (Chemical Equation Presented).
- Liu, Lantao,Zhang, An-An,Zhao, Rui-Juan,Li, Feng,Meng, Tuan-Jie,Ishida, Naoki,Murakami, Masahiro,Zhao, Wen-Xian
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- Palladium-Catalyzed C-H Functionalization of Ferrocenecarboxylic Acid by using 8-Aminoquinoline as a Removable Directing Group
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A mild and efficient palladium-catalyzed synthetic method for the C-H functionalization of N-(quinolin-8-yl)ferrocenecarboxamide has been developed. Various aryl iodides containing I, NO2, CN, COMe, CO2Et, and NH functionalities and also alkyl iodides underwent the Pd-catalyzed intermolecular carbon-carbon bond forming reaction with ferrocenecarboxamide successfully which led to a diverse array of bis(aryl/alkyl)ferrocenecarboxamides in 34-92% yields. Cross-coupling of the ferrocenyl C-H bond with aryl iodides can also be achieved utilizing an economical Ni catalyst. Additionally, selective monoalkylation of ferrocenecarboxamide was studied using sodium bicarbonate as base and dibenzylphosphoric acid as additive under Pd-catalyzed reaction conditions. Subsequently, removal of the directing group, 8-aminoquinoline, from bis(aryl)ferrocenecarboxamides led to bis(aryl)ferrocenes bearing versatile methyl ester and carboxaldehyde functional groups.
- Sattar, Moh.,Praveen,Durga Prasad, Ch.,Verma, Ajay,Kumar, Shailesh,Kumar, Sangit
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- Electrochemical Assay for Extremely Selective Recognition of Fructose Based on 4-Ferrocene-Phenylboronic Acid Probe and β-Cyclodextrins Supramolecular Complex
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The aim of the present paper is to highlight a novel electrochemical assay for an extremely-selective detection of fructose thanks to the use of a supramolecular complex between β-cyclodextrins (β-CDs) and a chemically modified ferrocene with boronic acid named 4-Fc-PB/natural-β-CDs. Another kind of β-CDs, the 4-Fc-PB/3-phenylboronic-β-CDs, is proposed for the detection of glucose. The novel electrochemical probe is fully characterized by 1H nuclear magnetic resonance, mass spectroscopy, and elemental analysis, while the superior electrochemical performance is assessed in terms of sensitivity and detection limit. The novelty of the present work consists in the role of CDs that for the first time are employed in electrochemistry with a unique detection mechanism based on specific chemical interactions with the target molecule by the introduction of proper binding groups. A?highly selective detection of fructose is obtained and it is believed that the proposed mechanism of detection represents a new way to electrochemically sense other molecules by varying the combination of specific groups of the supramolecular complex. The findings are of impactful importance since a quick, easy, cheap, and extremely selective detection of fructose is not yet available in the market, here achieved by using electrochemical methods which are a very growing field.
- Casulli, Maria Antonietta,Taurino, Irene,Hashimoto, Takeshi,Carrara, Sandro,Hayashita, Takashi
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- Functionalized ferrocenes: The role of the para substituent on the phenoxy pendant group
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Six ferrocenecarboxylates with phenyl, 4-(1H-pyrrol-1-yl)phenyl, 4-fluorophenyl, 4-chlorophenyl, 4-bromophenyl, 4-iodophenyl as pendant groups were synthesized and fully characterized by spectroscopic, electrochemical and X-ray diffraction methods. The anti-proliferative activity of these complexes were investigated in hormone dependent MCF-7 breast cancer and MCF-10A normal breast cell lines, to determine the role of the para substituent on the phenoxy pendant group. The 4-fluorophenyl ferrocenecarboxylate is inactive in both cell lines while 4-(1H-pyrrol-1-yl)phenyl ferrocenecarboxylate is highly cytotoxic in both cell lines. 4-chlorophenyl and 4-bromophenyl ferrocenecarboxylates have moderate to good anti-proliferative activity in MCF-7 and low anti-proliferative activity on normal breast cell line, MCF-10A whereas the 4-iodophenyl analog is highly toxic on normal breast cell line. The phenyl ferrocenecarboxylate has proliferative effects on MCF-7 and is inactive in MCF-10A. Docking studies between the complexes and the alpha-estrogen receptor (ERα) were performed to search for key interactions which may explain the anti-proliferative activity of 4-bromophenyl ferrocenecarboxylate. Docking studies suggest the anti-proliferative activity of these ferrocenecarboxylates is attributed to the cytotoxic effects of the ferrocene group and not to anti-estrogenic effects.
- Vera, José L.,Rullán, Jorge,Santos, Natasha,Jiménez, Jesús,Rivera, Joshua,Santana, Alberto,Briggs, Jon,Rheingold, Arnold L.,Matta, Jaime,Meléndez, Enrique
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- Synthesis, characterization and electrical conductance of ferrocenylazobenzene
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Ferrocenylazobenzene was synthesized by condensing an aminoazobenzene dye with ferrocenecarboxylic acid previously treated with oxalyl chloride. The compound displayed an anticipated chemically reversible one-electron oxidation process and gave a formal potential, E° = 0.65 V. In the UV-Vis region, the azo π-π and n-π transitions appeared at 355 and 460 nm respectively. On oxidation of the ferrocenyl moiety, the azo π-π band was blue-shifted to 348 nm with an increase in intensity, while a new broad, lower energy absorption band assigned to the ligand-to-metal charge transfer appeared at 622 nm. The growth of this new band was concurrent with the bleaching of the metal-to-ligand charge transfer band which was largely obscured by the azo n-π band at 460 nm. The compound in the form of thin film gave an average electrical conductivity of 0.239 ± 0.001 Scm-1 and a non-linear I-V curve with knee voltage at 2.3 V in dark condition.
- Tagg, Tei,Jamali, Siti Athirah Mohamad,Salleh, Hasiah,Hegde, Gurumurthy
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- N-Cobaltocenium Amide as Reactive Nucleophilic Reagent for Donor-Acceptor Bimetallocenes
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Deprotonation of the aminocobaltocenium ion [Cc-NH2]+ ([H-1]+) generates the nucleophilic imine CcNH (1). Reaction of 1 with acid chlorides R-COCl (R = Ph, Fc, and Cc+) yields the reference amide [Ph-CO-NH-Cc]+ (2+) and the amide-linked hetero- and homobimetallocenes [Fc-CO-NH-Cc]+ (3+) and [Cc-CO-NH-Cc]2+ (42+), respectively. Cation-anion interactions of charged amides 2+-42+ in the solid state and in solution are probed by single crystal X-ray diffraction and NMR and IR spectroscopy. Intramolecular metal-metal interactions in donor-acceptor heterobimetallocene 3+ and in mixed-valent homobimetallocene 4+ (prepared electrochemically) are discussed within the Marcus-Hush framework aided by spectroelectrochemical experiments and time-dependent density functional theory calculations.
- Lauck, Maximilian,F?rster, Christoph,Heinze, Katja
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- Synthesis of Chiral-Substituted 2-Aryl-ferrocenes by the Catellani Reaction
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A palladium-catalyzed and norbornene-mediated methodology has been developed for the synthesis of chiral 2-aryl-ferroceneamides from chiral 2-iodo-N,N-diisopropylferrocencarboxamide, iodoarenes, and alkenes using a JohnPhos ligand and potassium carbonate as a base in dimethylformamide at 105 °C. The developed three-component coupling protocol allows the compatibility of electron-withdrawing fluoro, chloro, ester, and nitro and electron-donating methyl, methoxy, dimethoxy, benzyl ether-substituted iodo-benzenes, other iodoarenes, such as iodo-naphthalene, heteroarenes, such as iodothiophene, and terminating substrates, such as methyl, ethyl, tert-butyl acrylates, and substituted styrenes with 2-iodo-N,N-diisopropylferrocencarboxamide. Furthermore, the developed three-component Catellani method proceeded with the retention of the configuration of the planar chiral ferrocene, which depends on the role of the participating carbon-iodine bond in ferrocene. Consequently, the developed protocol enabled the formation of densely substituted chiral 2-aryl ferroceneamides, exhibiting good to excellent enantioselectivity. The conversion of an ester of the synthesized chiral 2-aryl ferroceneamides has also been carried out to further accommodate the easily expendable acid and alcohol functionalities.
- Thorat, Raviraj Ananda,Jain, Saket,Sattar, Moh.,Yadav, Prateek,Mandhar, Yogesh,Kumar, Sangit
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- Self-assembled bio-organometallic nanocatalysts for highly enantioselective direct aldol reactions
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Supramolecular nanocatalysts were designed for asymmetric reactions through the self-assembly process of a bio-organometallic molecule, ferrocene-L-prolinamide (Fc-CO-NH-P). Fc-CO-NH-P could self-assemble into versatile nanostructures in water, including nanospheres, nanosheets, nanoflowers, and pieces. In particular, the self-assembled nanoflowers exhibited a superior specific surface area, high stability, and delicate three-dimensional (3D) chiral catalytic active sites. The nanoflowers could serve as heterogeneous catalysts with an excellent catalytic performance toward direct aldol reactions in aqueous solution, achieving both high yield (>99%) and stereoselectivity (anti/syn = 97:3, ee% >99%). This study proposed a significant strategy to fabricate supramolecular chiral catalysts, serving as a favorable template for designing new asymmetric catalysts.
- Yang, Xuejiao,Zhang, Liwei,Liang, Yaoyu,Wang, Yuefei,Shen, Yuhe,Xing, Qiguo,Qi, Wei,Wang, Pengfei,Liu, Xiao,Yang, Mengyao,Su, Rongxin,He, Mingxia,He, Zhimin
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- Ferrocene derivatives of liquid chiral molecules allow assignment of absolute configuration by X-ray crystallography
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The present study investigates a synthetically simple ferrocene derivatization of natural products and active pharmaceutical ingredients. Seven new crystal structures are analyzed together with 16 structures of ferrocene derivatives reported previously. In all cases, the unambiguous determination of the absolute structure was established from anomalous dispersion using the methods of Flack and Parsons. A comparison with other derivatization approaches shows the advantage of the described ferrocene derivatization for establishing the absolute configuration of novel compounds.
- Holstein, Philipp M.,Holstein, Julian J.,Escudero-Adán, Eduardo C.,Baudoin, Olivier,Echavarren, Antonio M.
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- Synthesis and characterization of novel ferrocene-containing pyridylamine ligands and their ruthenium(II) complexes: Electronic communication through hydrogen-bonded amide linkage
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Tris(2-pyridylmethyl)amine (TPA) derivatives with one or two ferrocenoylamide moieties at the 6-position of one or two pyridine rings of TPA were synthesized. The compounds, N-(6-ferrocenoylamide-2-pyridylmethyl)-N,N- bis(2-pyridylmethyl)amine (Fc-TPA; L1) and N,N-bis(6-ferrocenoylamide-2- pyridylmethyl)-N-(2-pyridylmethyl)amine (Fc2-TPA; L2), were characterized by spectroscopic methods, cyclic voltammetry, and X-ray crystallography. Their Ru(II) complexes were also prepared and characterized by spectroscopic methods, cyclic voltammetry, and X-ray crystallography. [RuCl(L1)(DMSO)]PF6 (1) that contains S-bound dimethyl sulfoxide (DMSO) as a ligand and an uncoordinated ferrocenoylamide moiety exhibited two redox waves at 0.23 and 0.77 V (vs ferrocene/ferrocenium ion as 0 V), due to Fc/Fc+ and Ru(II)/Ru(III) redox couples, respectively. [RuCl(L2)]PF6 (2) that contains both coordinated and uncoordinated amide moieties showed two redox waves that were observed at 0.27 V (two electrons) and 0.46 V (one electron), assignable to Ru(II)/Ru(III) redox couples overlapped with the uncoordinated Fc/Fc+ redox couple and the coordinated Fc/Fc+, respectively. In contrast to 2, an acetonitrile complex, [Ru(L2)(CH3CN)](PF6)2 (3), exhibited three redox couples at 0.26 and 0.37 V for two kinds of Fc/Fc+ couples, and 0.83 V for the Ru(II)/Ru(III) couple (vs ferrocene/ferrocenium ion as 0 V). In this complex, the redox potentials of the coordinated and the uncoordinated Fc-amide moieties were discriminated in the range of 0.11 V. Chemical two-electron oxidation of 1 gave [RuIIICl(L1 +)(DMSO)]3+ to generate a ferromagnetically coupled triplet state (S = 1) with J = 13.7 cm-1 (H = -JS1S 2) which was estimated by its variable-temperature electron spin resonance (ESR) spectra in CH3CN. The electron spins at the Ru(III) center and the Fe(III) center are ferromagnetically coupled via an amide linkage. In the case of 2, its two-electron oxidation gave the same ESR spectrum, which indicates formation of a similar triplet state. Such electronic communication may occur via the amide linkage forming the intramolecular hydrogen bonding.
- Kojima, Takahiko,Noguchi, Daisuke,Nakayama, Tomoko,Inagaki, Yuji,Shiota, Yoshihito,Yoshizawa, Kazunari,Ohkubo, Kei,Fukuzumi, Shunichi
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- Synthesis, anti-migration properties and burning rate catalytic properties of ferrocene-based compounds
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Five ferrocene (Fc)-based compounds (HQ-Fcs) were synthesized by the condensation reaction of ferrocenecarbonyl chloride with corresponding hydroquinone derivatives. Nuclear magnetic resonance (1H NMR), and Fourier transform infrared (FT-IR) we
- Usman, Muhammad,Wang, Li,Yu, Haojie,Haq, Fazal,Liang, Ruixue,Ullah, Raja Summe,Khan, Amin,Nazir, Ahsan,Elshaarani, Tarig,Naveed, Kaleem-ur-Rehman
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- Acylderivate der Ferrocenchalkogenole Fe(C5H5)(C5H4EH) und Fe(C5H4EH)2 (E=S, Se, Te)
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A series of nine ferrocene chalcogenol derivatives of the type Fe(C5H5)(C5H4EC(O)R) and of nine 1,1'-ferrocene dichalcogenol derivatives of the type Fe(C5H4EC(O)R)2 has been prepared in which the chalcogen (E=S, Se, Te) and the acyl group (C(O)R=benzoyl, 2-thenoyl, ferrocenoyl) were systematically varied.The crucial step of the synthesis includes insertion of the chalcogen E into the Li-C bond of the lithioferrocene to give the chalcogenolate intermediate Fe(C5H5)(C5H4ELi) or Fe(C5H4ELi)2, respectively, to be subsequently treated with the acyl chloride, RC(O)Cl.The 1H and 13C NMR spectra of the new compounds are discussed.
- Herberhold, Max,Leitner, Peter,Doernhoefer, Christine,Ott-Lastic, Jutta
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- Cyclopalladation of a ferrocene acylphosphine and the reactivity of the C-H activated products
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Acylphosphines are an attractive subclass of phosphine ligands with specific reactivity and ligating properties. This study describes the synthesis of a ferrocene-based acylphosphine, FcC(O)PPh2 (1, Fc = ferrocenyl), the corresponding phosphine chalcogenides FcC(O)P(E)Ph2 (E = O, S and Se), and palladium(ii) complexes resulting from the orthometallation of 1, viz. [Pd(μ-X)(1 - H)]2 (2-X, where X = Cl, Br and I), which in turn serve as a convenient entry point to a range of monopalladium complexes. Thus, the cleavage of 2-X with phosphines, 4-(dimethylamino)pyridine and in situ-generated 1,3-dimesitylimidazolin-2-ylidene (L) provided complexes [PdX(L)(1 - H)] (3-5), which are typically obtained as single isomers by crystallisation but undergo spontaneous isomerisation in solution leading to equilibrium mixtures of cis and trans isomers. Upon treatment with sodium acetylacetonate (Na(acac)), 2-Cl was transformed into [Pd(acac)(1 - H)] (6), which reacted with (diphenylphosphino)acetic acid under proton transfer to give [Pd(Ph2PCH2CO2-κ2O,P)(1 - H)] (7), while the reaction with allylating agents produced the π-allyl complex [Pd(η3-C3H5)(1 - H)] (9). Compound [PdCl(PMe3)(1 - H)] was further used to prepare a series of diorganopalladium complexes [Pd(R)(PMe3)(1 - H)] (8; R = Me, 4-C6H4Me, 4-C6H4CF3, CHCHC6H4Me-4 and CCC6H4Me-4). All compounds were structurally characterised using spectroscopic methods and, in most cases, also by X-ray diffraction analysis. The structural data indicated the rigidity of the Pd(1 - H)+ fragment and revealed variations in the Pd-donor distances dictated by an interplay between the trans influence and steric demands of the ligands surrounding Pd(ii). Moreover, some compounds were studied by DFT to rationalise their isomerisation equilibria and electrochemical properties, which were examined by cyclic voltammetry.
- Vosáhlo, Petr,Schulz, Ji?í,Císa?ová, Ivana,?těpni?ka, Petr
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- Cobalt-Catalyzed C?H Alkoxylation of Ferrocenes with Alcohols under Mild Conditions
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Herein we reported a protocol for synthesis of oxy-substituted ferrocenes via cobalt-catalyzed direct C?H alkoxylation under mild conditions. Notably, alcohol serves as an both alkoxide reagent and a solvent. Various ferrocene amides including estrone-derived ferrocene amide are compatible with these reaction conditions. Moreover, control experiments suggested that this alkoxylation might undergo a Co(III)/Co(IV)/Co(II) catalytic cycle. (Figure presented.).
- Cheng, Jie,Yao, Qi-Jun,Yue, Qiang,Zhang, Zhuo-Zhuo,Zhou, Gang
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- The crystal structures, molecular spectra and thermal behaviour of carbamoylferrocene and ferrocenecarbonylhydrazide
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Carbamoylferrocene (1) and ferrocenecarbonylhydrazide (2) were synthesised by modified literature procedures and studied by a combination of the conventional spectroscopic methods (IR, MS and NMR), X-ray crystallography and thermal analysis. The crystal structures of two new polymorphs of amide 1 and the structure of hydrazide 2 were determined, revealing extensive hydrogen bonding interactions of the polar ferrocene substituents and supportive π?π stacking interactions. Whereas the thermal behaviour of hydrazide 2 was relatively complicated, thermolysis of amide 1 in the presence of air oxygen led to a complete elimination of the organic constituents in a single step under mild conditions affording essentially pure hematite (α-Fe2O3). Mo?ssbauer spectra, powder X-ray diffraction and high-resolution transmission electron microscopy indicated the pyrolytic hematite to result in the form of random aggregates of well crystalline nanoparticles.
- ?těpni?ka, Petr,Císa?ová, Ivana,Ni?ňansky, Daniel,Bakardjieva, Snejana
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- Synthesis and catalytic performance of ferrocene-based compounds as burning rate catalysts
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To overcome migration problems of ferrocene-based burning rate catalysts and to enhance burning rate of ammonium perchlorate (AP)-based propellants, eleven ferrocene-based compounds (1–11) were synthesized by the condensation reaction of ferrocenecarbonyl chloride with corresponding amines and alcohols. The synthesis of 1–11 was confirmed using 1H NMR, Fourier transform infrared and UV–visible spectroscopy. Their electrochemical properties were analyzed using cyclic voltammetry. The compounds showed redox behavior due to the presence of ferrocene. Their catalytic behavior in the thermal decomposition of AP was investigated using thermogravimetry (TG) and differential TG (DTG). In the presence of 5?wt% 1–11, the thermal decomposition temperature of AP was significantly decreased. TG and DTG analyses showed that 1–11 had a good catalytic effect in the thermal decomposition of AP. Anti-migration studies showed that migration of 1–11 was slower than that of 2,2-bis(ethylferrocenyl)propane (catocene) and ferrocene. The effect of the presence of polar elements like oxygen and nitrogen on anti-migration behavior of small ferrocene-based compounds was also investigated. Oxygen-containing compounds showed better anti-migration behavior than nitrogen-containing compounds.
- Zain-ul-Abdin,Wang, Li,Yu, Haojie,Saleem, Muhammad,Akram, Muhammad,Khalid, Hamad,Abbasi, Nasir M.,Khan, Rizwan Ullah
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- Study on anion electrochemical recognition based on a novel ferrocenyl compound with multiple binding sites
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A novel ferrocenyl anion receptor N,N,N,N-(dimethyl, ethyl, ferrocenecarboxylic amidodimethylene) ammonium fluoborate 2 with multiple binding sites was synthesized. Its anion recognition behaviors were investigated by CV, 1H NMR and UV-vis spectrum. It was found that the combination of two interactions enforced the anion binding ability and the binding selectivity of 2 to phosphate anion. The effects of scan rate on the CV curves of 2 with phosphate were also investigated. In different scan rate, the CV curves kept stable which indicated the strong binding between 2 and phosphate. According to relationships of peak potential, peak currents and scan rate of 2 binding with phosphate, the kinetic parameters of electrode process such as diffusion coefficient Dapp, surface transfer coefficient αnα, and standard rate constant k0 were calculated.
- Tan, Qiaohua,Wang, Li,Ma, Liang,Yu, Haojie,Ding, Jianhua,Liu, Qingquan,Xiao, Anguo,Ren, Guoqing
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- Synthesis, Structural Reassignment, and Antibacterial Evaluation of 2,18-Seco-Lankacidinol B
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Lankacidins are a group of polyketide natural products with activity against several strains of Gram-positive bacteria. We developed a route to stereochemically diverse variants of 2,18-seco-lankacidinol B and found that the stereochemical assignment at C4 requires revision. This has interesting implications for the biosynthesis of natural products of the lankacidin class, all of which possessed uniform stereochemistry prior to this finding. We have evaluated 2,18-seco-lankacidinol B and three stereochemical derivatives against a panel of pathogenic Gram-positive and Gram-negative bacteria.
- Yao, Yanmin,Cai, Lingchao,Seiple, Ian B.
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- Synthesis of ferrocene-based saccharides and their anti-migration and burning rate catalytic properties
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In the search for ferrocene-based burning rate catalysts (BRCs) with good burning rate catalytic properties and low migration, we synthesized four ferrocene-based saccharides (S-Fcs). The synthesis of S-Fcs was confirmed by energy-dispersive X-ray (EDX), nuclear magnetic resonance (1H NMR), Fourier transform infra-red (FT-IR) and ultraviolet-visible (UV-Vis) spectroscopy. The electrochemical behavior of ferrocene-based BRCs is important to investigate the electron transfer burning rate catalytic mechanism. Therefore, the electrochemical behavior of the S-Fcs was investigated by cyclic voltammetry. The burning rate catalytic properties of the S-Fcs on thermal disintegration of ammonium perchlorate (AP) were determined by TG and DTG techniques. Thermal analysis results showed that the S-Fcs were thermally stable and showed good burning rate catalytic effects on thermal disintegration of AP. The S-Fcs were also analyzed in anti-migration studies in comparison with the most commonly used ferrocene-based burning rate catalyst (catocene) and ferrocene. It was found that S-Fcs showed excellent anti-migration behavior in AP-based propellant as compared to catocene and ferrocene.
- Zain-Ul-Abdin,Wang, Li,Yu, Haojie,Saleem, Muhammad,Abbasi, Nasir M.,Khan, Rizwan Ullah,Ullah, Raja Summe,Haroon, Muhammad
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- A two-step palladium-catalyzed coupling scheme for the synthesis of ferrocene-labeled amino acids
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This work describes a Pd-catalyzed coupling of ferrocene alkyne derivatives to iodo amino acids. Ferrocene carboxylic acid propargyl amides were easily obtained in high yield. The crystal structures of the propargyl amine derivative 3 and the 1,1-diethylpropargylamine derivative 4 have been determined by X-ray diffraction. Pd-catalyzed coupling to p-iodoanilide amino acids gave the corresponding ferrocene-labeled amino acid derivatives, which were easily purified by diethyl ether extraction in the case of the 1,1- diethyl derivatives 8. The coupling reaction did not require anhydrous solvents and tolerated a variety of functional groups present in peptides such as alcohols (8a, Ser), thioethers (8b, Met), disulfide bonds (cystine, 12) esters (as in the N-labeled Leu derivative 10) and of course amides. A minor by-product of the coupling reaction, namely the homo-dimer bis(ferrocene carboxylic acid propargylamide) 9, was identified in the crude reaction mixtures by mass spectrometry and independently synthesized by oxidative coupling (Glaser and Eglington) of 3. All new compounds were completely characterized spectroscopically, including 15N- and 2D NMR spectroscopy, Mossbauer spectroscopy and electrochemistry. This work introduces a versatile procedure for a selective functionalization of amino acids with organometallics at the C-terminus which is expected to be of general applicability to peptide chemistry.
- Brosch, Oliver,Weyhermueller, Thomas,Metzler-Nolte, Nils
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- Asymmetric intermolecular cyclopropanation of alkenes and N–H insertion of aminoesters by diazoacetylferrocene catalyzed by ruthenium and iron porphyrins
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The asymmetric addition of diazoacetylferrocene to styrene derivatives to give optically active cyclopropyl acetylferrocenes (ee up to 96%) was carried out using chiral ruthenium porphyrins as homogeneous catalysts. Intermolecular N–H functionalization of
- Carrié, Daniel,Roisnel, Thierry,Simonneaux, Gérard
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- Approach to ferrocenyl-podophyllotoxin analogs and their evaluation as anti-tumor agents
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Podophyllotoxin is a natural product endowed of a high antimitotic activity and a high affinity for tubulin. Its action results in the cessation of cell division, inducing cell death. However, its high toxicity restrains its use as drug. To overcome this drawback, several chemical modifications of the native podophyllotoxin have been made. However, to date, no reports have so far been directed toward incorporation of a metallocene moiety. The search for new organometallic drugs is a central field in drug discovery, including the domain of cancer therapy. In particular, metallocenyl moieties are known to increase or decrease, depending on the degree of conjugation in the organometallic motif, the selectivity of drugs toward cancer cells. The conjugate organometallic compound reduces the damage of healthy tissues, yet permitting the selective desired antimitotic and cytotoxic effects of the active principle. We report here the synthesis of ferrocene-containing podophyllotoxin analogs and preliminary antiproliferative tests.
- Beaupérin, Matthieu,Polat, Dilan,Roudesly, Fares,Top, Siden,Vessières, Anne,Oble, Julie,Jaouen, Gérard,Poli, Giovanni
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- Ferrocenoyl-Substituted Pyrimidine Nucleobases: An Experimental and Computational Study of Regioselective Acylation of Uracil, Thymine, and 5-Fluorouracil
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Uracil, thymine, and 5-fluorouracil (5-FU) have been ferrocenoylated selectively at the N1 position. Deprotonated pyrimidine nucleobases, prepared with sodium hydride (NaH) in N,N-dimethylformamide (DMF), reacted with either ferrocenoyl chloride (FcCOCl) or ferrocenoyl ethyl carbonate (FcCOOCOOEt), in DMF to give a single product. The regioselectivity of these reactions were analyzed in detail by using NMR spectroscopy and quantum chemical calculations. The 1H and 19F NMR spectra of reaction mixtures, and 13C NMR and 2D NOESY spectra of products, confirmed the formation of the N1-isomer only. The calculated energy barrier for acetylation at the N3-position is significantly higher (> 40 kJ/mol), which suggests that the analogous reaction at the N1-position is kinetically controlled. The nucleophilic addition of pyrimidine bases to the carbonyl group of FcCOCl proceeds through a concerted SN2-like mechanism with the absence of the generally assumed tetrahedral intermediate. NMR spectroscopy and quantum chemical calculations (DFT) were employed to rationalize the regioselectivity in the formation of ferrocenoyl-substituted pyrimidine nucleobases. A facile one-step method is reported for the synthesis of N1-substituted derivatives.
- Lapic, Jasmina,Havaic, Valentina,akic, Davor,Sankovic, Kreimir,Djakovic, Senka,Vrek, Valerije
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- Electron Transfer between Amphiphilic Ferrocenes and Electrodes in Cationic Micellar Solution
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Standard heterogeneous electron-transfer rate constants (k') for ferrocene (Fc) esters attached to the 2- and 5-carbon atoms (I and II) away from nitrogen on the hydrocarbon chain of dodecyltrimethylammonium ions were similar to each other and to ferrocene (Fc) in homogeneous organic solvent.However, in micellar solutions of cetyltrimethylammonium bromide (CTAB), differences were found for k' in the order Fc > I > II.Activation free energies from temperature dependences of k' and microenvironmental polarities from spectroscopic studies were similar for I and II in CTAB solutions, suggesting similar reorganization energies.The distance dependence of k' in micellar solution was consistent with predictions of Marcus theory using a through-space model with average distances of electron transfer estimated from molecular dynamics or a through-bond model assuming bonding of head groups to the electrode.Results suggest that CTAB adsorbed to the electrode helps to orient the electroactive surfactants with alkylammonium head groups down on the Pt surface prior to electron transfer.Electron transfer to Pt from Fc in cationic micellar solutions occurs over a shorter distance than for I.
- Abbott, Andrew P.,Gounili, Giv,Bobbitt, James M.,Rusling, James F.,Kumosinski, Thomas F.
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- Covalently Attached Porphycene-Ferrocene Dyads: Synthesis, Redox-Switched Emission, and Observation of the Charge-Separated State
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Two new porphycenes functionalized with ferrocenyl pendants have been synthesized and characterized spectroscopically and structurally. The porphycene-based emission in porphycene-ferrocene dyads was switched on and off by the reversible control of the ferrocenyl pendant redox states. Transient absorption spectroscopy with a femtosecond laser-pulsed technique has successfully detected the picosecond charge-separated excited state of the dyad upon Q-band excitation of the porphycene ring.
- Abe, Masaaki,Yamada, Hiroaki,Okawara, Toru,Fujitsuka, Mamoru,Majima, Tetsuro,Hisaeda, Yoshio
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- Tris(2-aminoethyl)amine-based ferrocene-terminated dendrimers as burning rate catalysts for ammonium perchlorate-based propellant decomposition
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Ferrocene-based derivatives show potential application as burning rate catalysts (BRCs) for solid composite propellants. However, migration problems of simple ferrocene-based derivatives limit their application as BRCs in solid composite propellants. To o
- Zain-ul-Abdin,Wang, Li,Yu, Haojie,Khan, Rizwan Ullah,Ullah, Raja Summe,Haroon, Muhammad
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- Alkali-metal binding properties of simple ferrocenyl- and ruthenocenyl-substituted aza-crown ethers
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Reaction of 1-chlorocarbonyl-ferrocene or -ruthenocene with aza-15-crown-5 (1,4,7,10-tetraoxa-13-aza-cyclopentadecane) afforded the respective amide-linked metallocene crowns. Nucleophilic displacement of trimethylamine from trimethylammoniomethyl-ferrocene or -ruthenocene iodides with aza-15-crown-5 yielded the corresponding methylene-linked crowns. Variable-temperature 13C NMR investigation of the hindered rotation about the amide links of the amide-linked crowns in the presence of guest cations indicated that cation complexation occurs exclusively within the crown ring. Extraction experiments with a range of metal-cation dye salts revealed a favourable binding capacity for the methylene-linked crowns. Detailed 13C NMR analysis of sodium and potassium ion binding by these systems suggests the presence of a stabilising interaction between the metallocene π system and the crown-bound cation. Cyclic voltammetric analysis of metal-ion binding by the amine-linked crowns revealed cation-induced shifts of the appropriate redox couple comparable with those reported for related systems.
- Grossel, Martin C.,Hamilton, Darren G.,Fuller, Jason I.,Millan-Barios, Enrique
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- Electrochemistry at the air/water interface. Lateral diffusion of an octadecylferrocene amphiphile in langmuir monolayers
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A new electrochemical method is described to investigate the dynamics of lateral diffusion processes in Langmuir monolayers at the air/water interface. The key element of this technique is a gold microband electrode, which can be positioned in the plane of the water surface and which functions as a 1D electrode in contact with a 2D collection of electroactive, water insoluble molecules. Investigations of N-octadecylferrocenecarboxamide (C18Fc) monolayers and mixed monolayers of C18Fc and octadecanol on 0.05 M HClO4 at 28 °C showed that they remain fluid without undergoing any phase transitions, in a surface concentration range of 3.3 × 10-10 to 7 × 10-11 mol/cm2. Lateral diffusion of C18Fc can be modeled as a 2D fluid of hard disks with the cross sectional area equal to the projected area of the ferrocene head group. The diffusion coefficient increases linearly with the average free area per molecule on the water surface.
- Charych, Deborah H.,Landau, Ehud M.,Majda, Marcin
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- Tetrablock Metallopolymer Electrochromes
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Multi-block polymers are highly desirable for their addressable functions that are both unique and complementary among the blocks. With metal-containing polymers, the goal is even more challenging insofar as the metal properties may considerably extend the materials functions to sensing, catalysis, interaction with metal nanoparticles, and electro- or photochrome switching. Ring-opening metathesis polymerization (ROMP) has become available for the formation of living polymers using highly efficient initiators such as the 3rd generation Grubbs catalyst [RuCl2(NHC)(=CHPh)(3-Br-C5H4N)2], 1. Among the 24 possibilities to introduce 4 blocks of metallopolymers into a tetrablock metallocopolymer by ROMP using the catalyst 1, two viable pathways are disclosed. The synthesis, characterization, electrochemistry, electron-transfer chemistry, and remarkable electrochromic properties of these new nanomaterials are presented.
- Gu, Haibin,Ciganda, Roberto,Castel, Patricia,Moya, Sergio,Hernandez, Ricardo,Ruiz, Jaime,Astruc, Didier
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- Preparation and biodistribution of 1-((2-methoxyphenyl) piperazine)ferrocenecarboxamide labeled with technetium-99m as a potential brain receptor imaging agent
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The goal of this study is to develop a novel brain receptor imaging agent. This study reports the synthesis, characterization and the biological evaluation of 1-((2-methoxyphenyl) piperazine)ferrocenecarboxamide labeled with technetium-99 m (99mTc-MP). The 99mTc-MP was obtained quickly (radiolabelling time 99mTc-complex, characterized by HPLC (20-50% ACN of 0 at 5 min then 50% ACN of 5 at 17 min to finally with 50 at 20% ACN of 17 at 20 min), is stable, neutral and lipophilic enough to cross the blood-brain barrier which was confirmed by octanol/water partition coefficient (LogP = 1.82). In vivo biodistribution indicated that this complex had exceptional brain uptake (2.47% ID/g at 5 min and 0.75% ID/g at 60 min). The distribution of the activity at 15 min post-injection in various rat brain regions showed a higher accumulation in the hippocampus area. After blocking with 8-hydroxy-2-(dipropylamino) tetralin, the uptake of hippocampus was decreased significantly from 0.87% ID/g to 0.21% ID/g at 15 min p.i., while the cerebellum had no significant decrease. The new 99mTc-cyclopentadienyltricarbonyl technetium complex reported here showed promising biological results, making it an interesting starting point for the development of a new 99mTc-complex as brain receptor imaging agent.
- Saied, Nadia Malek,Mejri, Najoua,El Aissi, Radhia,Benoist, Eric,Saidi, Mouldi
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- Synthesis and research of electrochemical behavior of magnetic nanocomposites based on Fe3O4
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The nanocomposites including magnetite nanoparticles, polymer coating and electrochemically active molecules were synthesized and investigated: poly(vinylbenzyl) chloride coating modified by quinoline; coating based on polypyrrole, silica coating modified
- Kozitsina,Malysheva,Verbitsky,Utepova,Glazyrina,Mitrofanova,Rusinov,Matern,Chupakhin,Brainina
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- Chiral oxazolinylferrocene-phosphine hybrid ligand for the asymmetric hydrosilylation of ketones
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A new type of chiral oxazolinylferrocene - phosphine hybrid is a very effective ligand for Rh(I)-catalyzed asymmetric hydrosilylation of simple ketones to give the corresponding sec-alcohols (91% ee) after acid hydrolysis. Similar reactions also proceed highly selectively (96% ee) by use of Ir(I) catalyst, but the configuration of the products is completely reverse.
- Nishibayashi, Yoshiaki,Segawa, Kyohei,Ohe, Kouichi,Uemura, Sakae
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- Synthesis, electrochemistry and IR spectroelectrochemistry of bisferrocenyl bridged benzene derivates
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Two novel biferrocenylcarboxylate benzene derivatives, namely, 1,4-bis(2-Ferrocenecarboxylate) benzene (Fc2B) and 1,4-bis(2-Ferrocenecarboxylate)-2′-methylbenzene (Fc2M), have been synthesized. The as-prepared complexes have been con
- Huang, Peng,Jin, Baokang,Liu, Peng,Cheng, Longjiu,Cheng, Wangxing,Zhang, Shengyi
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- Assessment of the nematocidal activity of metallocenyl analogues of monepantel
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In this study, we present the design, synthesis, characterization and biological evaluation of structurally new ferrocenyl and ruthenocenyl derivatives of the organic anthelmintic monepantel (Zolvix). All seven metallocenyl derivatives prepared (4a/b, 5a/b, 6a/b and 7) were isolated as racemates and characterized by 1H, 13C and 19F NMR spectroscopies, mass spectrometry, IR spectroscopy and elemental microanalysis. The molecular structures of four compounds (4a/b, 6a and 7) were further confirmed by X-ray crystallography. The biological activities of the organometallic intermediates (4a/b) and organometallic derivatives of monepantel (5a/b, 6a/b and 7) were evaluated in vitro using parasitic nematodes of major importance in livestock, namely Haemonchus contortus and Trichostrongylus colubriformis. Two ferrocenyl compounds (4a and 6a) showed nematocidal activity, while the analogous ruthenocenyl compounds (4b and 6b) were not active at the highest concentration tested (10 μg mL-1). In order to obtain insight into the difference in activity between ferrocenyl and ruthenocenyl derivatives, the potential of the compounds for reactive oxidative species (ROS) production in live cells was assessed. Interestingly, neither the ferrocenyl nor the ruthenocenyl compounds (4a/b and 6a/b) produced significant ROS in HeLa cells when checked after 22 h, potentially indicating a redox-independent activity of 4a and 6a on the parasites. The selectivity of the compounds on parasites was confirmed by investigating their cytotoxicity profiles. None of these compounds was toxic either to HeLa or MRC-5 cells. Thus, 4a and 6a could be considered as interesting leads for further development of new classes of anti-parasitic agents.
- Hess, Jeannine,Patra, Malay,Jabbar, Abdul,Pierroz, Vanessa,Konatschnig, Sandro,Spingler, Bernhard,Ferrari, Stefano,Gasser, Robin B.,Gasser, Gilles
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- Ferrocenecarboxylic anhydride: Identification of a new polymorph
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A new monoclinic polymorph of ferrocenecarboxylic anhydride, [Fe2(C5H5)2(C12H8O3)], was obtained. Three molecules are present in the asymmetric unit, two of them being nearly identical (r.m.s. deviation = 0.11 ?), with the Fe atoms on the same side of the anhydride functional group. In the third molecule, the two Fe atoms are located at opposite sides of the functional group (ferrocene-ferrocene pseudo-torsion angle = 146.2), a very unsual feature in metallocene anhydrides. A network of weak intermolecular hydrogen bonds was also disclosed.
- Tazi, Mehdi,Roisnel, Thierry,Mongin, Florence,Erb, William
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- Palladacycles Based on 8-Aminoquinoline Carboxamides of Cobalt and Iron Sandwich Compounds and a New Method to α-Alkylate Cp Rings of Metal Sandwich Carboxamides
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Reactions of {η5-C5H4[C(O)Cl]}Co(η4-C4Ph4) and {η5-C5H4[C(O)Cl]}Fe(η5-Cp) with 8-aminoquinoline resulted in cobalt and iron sandwich derived carboxamides. The reaction of these carboxamides with Pd(OAc)2 in acetonitrile resulted in αC-H activation of the Cp rings of the sandwich compounds and formation of novel palladacycles 3 and 4, having both N-H and one α-C-H hydrogen atom of the Cp ring displaced and palladium forming a square planar complex with acetonitrile as the fourth ligand. These air-stable palladacycles reacted with MeI and EtI in acetic acid, resulting in mono- and 2,5-di-α-alkylated sandwich carboxamides, thereby providing a new method to realize Cp-multisubstituted sandwich compounds. Selectivity in α-substitution was observed in the presence of NaHCO3. The cobalt sandwich carboxamide 1, the new palladacycles 3 and 4, and the 2,5-dimethylated cobalt sandwich carboxamide 5 have also been structurally characterized using single-crystal X-ray structural studies.
- Singh, Jatinder,Deb, Mayukh,Elias, Anil J.
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- Two convenient new syntheses of ferrocenoyl chloride by triphosgene
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Two convenient new syntheses of ferrocenoyl chloride by triphosgene were reported. Firstly, ferrocenoyl chloride was conveniently prepared in 61.5% yield when triphosgene was reacted with ferrocene carboxylic acid in methylene dichloride at room temperature in the presence of triethylamine and DMAP. This new method for the synthesis of ferrocenoyl chloride enjoys a number of advantages in that the reaction is carried out under mild conditions and is cleaner without the formation of POCl3, H3PO3 or SO2 and dark-colored impurities. Secondly, ferrocene underwent reaction with one-third equivalent of triphosgene to give ferrocenoyl chloride in 38.1% yield. The main advantage of the second method for the synthesis of ferrocenoyl chloride is using cheap ferrocene as starting material.
- Qingmin, Wang,Runqiu, Huang
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- Synthesis and properties of stimuli-responsive ferrocene-and azobenzene-based copolymers P(FHEMA-co-MAAT)s
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Three novel polymers (P(FHEMA-co-MAAT)s) having redox and photoresponsive moieties were prepared by free radical polymerization. The structures and molecular weights of the synthesized copolymers were characterized by nuclear magnetic resonance (1H NMR) and gel permeation chromatography (GPC) respectively. Thermal properties, optical features and electroactive properties were studied with the help of thermogravimetric (TG), differential thermogravimetric (DTG) analysis, ultraviolet-visible spectroscopy (UV-vis) and cyclic voltammetry (CV). It was seen that synthesized copolymers had excellent redox and photoresponsive properties. These results exhibited that these polymers can be applied further for redox/photo responsive information storage devices.
- Khan, Amin,Wang, Li,Yu, Haojie,Haroon, Muhammad,Ullah, Raja Summe,Nazir, Ahsan,Elshaarani, Tarig,Usman, Muhammad,Fahad, Shah,Naveed, Kaleem-ur-Rehman
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- Synthesis of poly(2-(methacryloyloxy) ethyl ferrocene carboxylate-co-methacrylic acid)s and their anti-migration and burning rate catalytic properties
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A series of copolymers of poly(2-(methacryloyloxy) ethyl ferrocene carboxylate-co-methacrylic acid)s (P(FHEMA-co-MAA)s) were synthesized as burning rate catalysts (BRCs). Their structures were verified using proton nuclear magnetic resonance (1H NMR) and Fourier transforms infrared (FT-IR) spectroscopy. The electrochemical behavior of P(FHEMA-co-MAA)s was investigated by cyclic voltammetry (CV). The CV results indicated that P(FHEMA-co-MAA)s showed redox behavior. Anti-migration test proved that P(FHEMA-co-MAA)s possesses better anti-migration properties than ferrocene (Fc) and 2, 2-bis (ethylferrocenyl) propane (Catocene). The burning rate (BR) catalytic effect of P(FHEMA-co-MAA)s on thermal decomposition of AP was examined through thermogravimetry (TG) and differential thermogravimetry (DTG). P(FHEMA-co-MAA)s were found to have high catalytic effects in accelerating thermal decomposition of ammonium perchlorate (AP).
- Elshaarani, Tarig,Fahad, Shah,Khan, Amin,Li, Xuefeng,Naveed, Kaleem-ur-Rehman,Nazir, Ahsan,Qian, Jianguo,Usman, Muhammad,Wang, Li,Yu, Haojie
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- Amide-Directed Cobalt(III)-Catalyzed C-H Amidation of Ferrocenes
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The amide-directed cobalt(III)-catalyzed C-H amidation of ferrocene carboxamides using 1,4,2-dioxazol-5-ones as robust and efficient amidating reagents has been developed. This reaction proceeds efficiently under mild reaction conditions with good functional group tolerance, providing expedient access to a broad range of ferrocenes containing a nitrogen group on the Cp ring.
- Huang, Dan-Ying,Yao, Qi-Jun,Zhang, Shuo,Xu, Xue-Tao,Zhang, Kun,Shi, Bing-Feng
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- Concise Asymmetric Syntheses of Streptazone A and Abikoviromycin**
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Streptazone A and abikoviromycin are alkaloids that both feature an unusual arrangement of reactive functionalities within a compact tricyclic ring system. Here, we report a highly concise asymmetric synthesis of both natural products. The route first constructs another family member, streptazone B1, using a rhodium-catalyzed distal selective allene-ynamide Pauson–Khand reaction. A regio- and enantioselective epoxidation under chiral phase-transfer catalytic conditions directly afforded streptazone A in 8 steps overall. In one additional step, a chemoselective, iridium-catalyzed reduction of the enaminone system then gave abikoviromycin. The reactivity of streptazone A towards a cysteine mimic, N-acetylcysteamine, was studied and revealed unanticipated transformations, including bis-thiol conjugation which may proceed via formation of a cyclopentadienone intermediate. With flexible access to these compounds, studies aimed to identify their direct biological targets are now possible.
- W?rmer, Gustav J.,Villadsen, Nikolaj L.,N?rby, Peter,Poulsen, Thomas B.
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- Synthesis of ferrocene[c]pyridin-2(1H)-one derivatives via Pd(II)-catalyzed C–H activation reaction under air
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A Pd(II)-catalyzed C–H activation annulation under air has been successfully developed for efficient synthesis of ferrocene[c]pyridin-2(1H)-one derivatives with high yields and good regiochemistry. This method shows highly atom- and step-economical access to prepare ferrocene-fused heterocycles under mild conditions.
- Liu, Hua-Yu,Mou, Rui-Qi,Sun, Chuan-Zhi,Zhang, Sheng-Yan,Guo, Dian-Shun
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- 2-(4′-Aminophenyl)benzothiazole Labeled with 99mTc-Cyclopentadienyl for Imaging β-Amyloid Plaques
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The development of a 99mTc-radiotracer for imaging of β-amyloid (Aβ) plaques with single photon emission computed tomography (SPECT) is strongly anticipated to provide a low cost and broadly accessible diagnostic tool for Alzheimer's disease (AD). Within this framework, 2-(4′-aminophenyl)benzothiazole, known to display affinity and specificity for Aβ plaques, has been joined to the tricarbonyl fac-[M(CO)3]+ (M = Re(I), 99mTc(I)) core through the cyclopentadienyl moiety to yield stable, neutral, and lipophilic complexes (Re-1 and 99mTc-1, respectively). The Re-1 complex was completely characterized with spectroscopic methods and was shown to selectively stain Aβ plaques on sections of human AD brain tissue. The 99mTc-1 complex displayed satisfactory initial brain uptake (0.53% ID/g at 2 min) and in vivo stability in healthy mice, while in transgenic 5xFAD mice, models for AD, a notable retention in the brain was noted (1.94% ID/g at 90 min). The results are encouraging and contribute to the effort of developing a SPECT amyloid imaging agent.
- Kiritsis, Christos,Mavroidi, Barbara,Shegani, Antonio,Palamaris, Lazaros,Loudos, George,Sagnou, Marina,Pirmettis, Ioannis,Papadopoulos, Minas,Pelecanou, Maria
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- Directed Iron-Catalyzed ortho-Alkylation and Arylation: Toward the Stereoselective Catalytic Synthesis of 1,2-Disubstituted Planar-Chiral Ferrocene Derivatives
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The iron-catalyzed directed ortho-functionalization of arenes developed to an important method in the field of C-H activation. On the other hand, the iron-catalyzed ortho-functionalization of ferrocenes bearing ortho-directing groups (ODGs) has scarcely been investigated. Herein we present the iron-catalyzed ortho-alkylation and -arylation of ODG-substituted ferrocenes bearing a bidentate ODG with the formation of racemic 1,2-disubstituted ferrocenes in up to 94% yield. The approach toward an enantioselective iron-catalyzed C-H activation resulted in an ortho-phenylation with a promising enantiomeric excess of 46%. The first iron-catalyzed diastereoselective ortho-methylation gave an excellent diastereomeric excess of ≥99%.
- Schmiel, David,Butensch?n, Holger
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- Synthesis and electrochemical properties of ferrocene formylated curcumin
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Ferrocene formylated curcumin was synthesized from ferrocene monocarboxylic acid and curcumin. Its structure was characterized by MS, IR and 1H NMR. The voltammetric behaviour of the new compound was investigated, appearing a pair of well defined redox wave at oxidation potential 0.768 V and reduction potential 0.219 V, respectively in the range of 0-1.0 V. The experimental result showed that curcumin had a great influence on the reversibility of the ferrocene, changing its oxidation peak position by the bridge of ester bond. It could have great current change in the range of 0-1.0 V, which is possible to be used as molecular level electronic switch.
- Xu, Xiu-Shang,Kong, Ling-Kai,Huai, Qi-Yong
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- Direct Synthesis of Enamides via Electrophilic Activation of Amides
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A novel, one-step N-dehydrogenation of amides to enamides is reported. This reaction employs the unlikely combination of LiHMDS and triflic anhydride, which serves as both the electrophilic activator and the oxidant, and is characterized by its simple setup and broad substrate scope. The synthetic utility of the formed enamides was readily demonstrated in a range of downstream transformations.
- Berger, Martin,Kaiser, Daniel,Maulide, Nuno,Spie?, Philipp
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supporting information
p. 10524 - 10529
(2021/07/28)
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- Diastereoselective Double C?H Functionalization of Chiral Ferrocenes with Heteroaromatics
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Diastereoselective double C?H heteroarylation of chiral ferrocenes provides valuable compounds with multiple functionalities using mild reaction conditions and simple reagents. Pd-Complexes with chiral mono-protected amino acids afforded corresponding heteroarylated ferrocenyl amines in good yields and high diastereomeric purities. In this way, a variety of indole, thiophene, pyrrole, or furan substituents were introduced to the ferrocene moiety. Furthermore, a range of relevant functional groups, for example ketone, ester, chloro, nitro, or silyl, are tolerated by this method. An alternative combination of amino acid and ferrocenyl amine configurations was leveraged to provide the complementary diastereomeric products. The products of C?H heteroarylation can be transformed into corresponding phosphines. Absolute configurations of CH-activation products were confirmed by the combination of X-ray crystallographic analysis and CD spectroscopy. 19F NMR kinetic study and DFT calculations provided insights into the reaction mechanism and reasons governing stereoinduction.
- Plevová, Kristína,Kisszékelyi, Péter,Vargová, Denisa,Andrej?ák, Samuel,Tóth, Viktor,Fertá?, Luká?,Rakovsky, Erik,Filo, Juraj,?ebesta, Radovan
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supporting information
p. 15501 - 15507
(2021/10/07)
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- N-Ammonium Ylide Mediators for Electrochemical C-H Oxidation
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The site-specific oxidation of strong C(sp3)-H bonds is of uncontested utility in organic synthesis. From simplifying access to metabolites and late-stage diversification of lead compounds to truncating retrosynthetic plans, there is a growing need for new reagents and methods for achieving such a transformation in both academic and industrial circles. One main drawback of current chemical reagents is the lack of diversity with regard to structure and reactivity that prevents a combinatorial approach for rapid screening to be employed. In that regard, directed evolution still holds the greatest promise for achieving complex C-H oxidations in a variety of complex settings. Herein we present a rationally designed platform that provides a step toward this challenge using N-ammonium ylides as electrochemically driven oxidants for site-specific, chemoselective C(sp3)-H oxidation. By taking a first-principles approach guided by computation, these new mediators were identified and rapidly expanded into a library using ubiquitous building blocks and trivial synthesis techniques. The ylide-based approach to C-H oxidation exhibits tunable selectivity that is often exclusive to this class of oxidants and can be applied to real-world problems in the agricultural and pharmaceutical sectors.
- Saito, Masato,Kawamata, Yu,Meanwell, Michael,Navratil, Rafael,Chiodi, Debora,Carlson, Ethan,Hu, Pengfei,Chen, Longrui,Udyavara, Sagar,Kingston, Cian,Tanwar, Mayank,Tyagi, Sameer,McKillican, Bruce P.,Gichinga, Moses G.,Schmidt, Michael A.,Eastgate, Martin D.,Lamberto, Massimiliano,He, Chi,Tang, Tianhua,Malapit, Christian A.,Sigman, Matthew S.,Minteer, Shelley D.,Neurock, Matthew,Baran, Phil S.
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supporting information
p. 7859 - 7867
(2021/05/26)
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- Supramolecular hydrogel capable of being decomposed through light control and preparation method and application thereof
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The invention discloses supramolecular hydrogel capable of being decomposed through light control and a preparation method and application thereof. According to the supramolecular hydrogel, hyaluronic acid is adopted as a gel network main chain, beta-cyclodextrin and ferrocene are respectively modified on the hyaluronic acid to serve as host and guest molecules, the supramolecular hydrogel is constructed by virtue of host-guest interaction, meanwhile, a photosensitizer is loaded in the network of the supramolecular hydrogel. The supramolecular hydrogel can be used for loading small molecular drugs. Under near-infrared irradiation, the photosensitizer releases active oxygen, and the active oxygen realizes the disassembly of the hydrogel through ferrocene oxide and causes the release of the loaded medicine, so that the on-demand release under the near-infrared irradiation is realized. The method is ingenious in design and easy to implement. The degradation of the supramolecular hydrogel is regulated and controlled by the near-infrared illumination position, illumination time and illumination power, so that the precise release of the loaded medicine can be realized by utilizing light-controlled degradation, and the supramolecular hydrogel has a good application prospect.
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Paragraph 0070; 0074
(2021/07/14)
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- Mitochondria-Targeted delivery and light controlled release of iron prodrug and CO to enhance cancer therapy by ferroptosis
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Mitochondrial malfunction is considered to be a decisive signal of apoptosis. It would be a promising strategy to target mitochondria in cancer cells to generate reactive oxygen species (ROS), thus directly inducing mitochondrial damage. We herein reported a mitochondria-Targeted, photo-responsive polymer (Mito-PNBE), which can self-Assemble into nanoparticles (Fe-CO@Mito-PNBE) encapsulated with diphenylcyclopropenone (light-responsive CO prodrugs) and aminoferrocene-based prodrugs via hydrophobic interactions. Upon UV-irradiation, the rapid release of CO and aminoferrocene-based prodrugs caused by disassembly was observed. On one hand, the released carbon monoxide in mitochondria could enhance ROS generation and accelerate oxidative metabolism. On the other hand, the aminoferrocene-based prodrugs will release Fe3+/Fe2+ ions in the tumor microenvironment, thus triggering the Fenton reaction, which generates more ROS and damages the mitochondria. Thus, the synergistic effect of the two drugs produces enough amounts of ROS in the mitochondria, leading to mitochondrial collapse with an enhanced cancer therapeutic effect. This multifunctional platform has potential in precision cancer therapy.
- Gao, Fan,Gao, Fan,Zhang, Wen-Jian,Hong, Chun-Yan,You, Ye-Zi,Nie, Xuan,Zhang, Ze,Chen, Guang,Xia, Lei,Wang, Long-Hai,Zhang, Wen-Jian,Hong, Chun-Yan,You, Ye-Zi,Wang, Fei,Wang, Chang-Hui,Hao, Zong-Yao
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supporting information
p. 3478 - 3486
(2020/03/06)
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- Synthesis of ferrocenylated-aminopyridines and ferrocenylated-aminothiazoles and their anti-migration and burning rate catalytic properties
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For overcoming the migration problems of ferrocene (Fc)-based burning rate catalysts (BRCs) as well as for enhancing burning rate (BR) of ammonium perchlorate (AP)-based propellants, ferrocenylated-amino pyridines (AP-Fcs) and ferrocenylated-amino thiazol
- Fahad, Shah,Khan, Amin,Lemenovskiy, Dmitry A.,Naveed, Kaleem-ur-Rehman,Nazir, Ahsan,Usman, Muhammad,Wang, Li,Yu, Haojie,Zarubin, Dmitry N.,Zhizhko, Pavel A.
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- Cp?Co(III)/MPAA-Catalyzed Enantioselective Amidation of Ferrocenes Directed by Thioamides under Mild Conditions
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Cp?Cobalt(III)-catalyzed enantioselective C-H amidation of ferrocenes using monoprotected amino acids (MPAAs) as chiral ligands was developed. The reaction was performed under mild conditions in high yields (up to 97%) with moderate enantioselectivity (up to 77.5:22.5 er), providing a promising strategy to create planar chirality via base-metal-catalyzed enantioselective C-H activation.
- Liu, Yan-Hua,Li, Peng-Xiang,Yao, Qi-Jun,Zhang, Zhuo-Zhuo,Huang, Dan-Ying,Le, Minh Dong,Song, Hong,Liu, Lei,Shi, Bing-Feng
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supporting information
(2019/03/19)
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- Carbon-Rich Trinuclear Octamethylferrocenophanes
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Several trinuclear ferrocenes are obtained by Friedel-Crafts reaction of octamethylferrocene with ferrocenoyl chloride and subsequent modifications. 1,1′-Diferrocenoyloctamethylferrocene (3) is transformed to the divinyl derivative (4a) by reaction with MeLi and AlCl3. The reactive 4a cyclizes spontaneously to a [4]ferrocenophane with buta-1,3-diene handle (5) or in the presence of AlCl3 to a [3]ferrocenophane with propene handle (6). Structure assignments are supported by X-ray crystallography and NMR spectroscopy, and mechanisms are proposed. Electrochemical behavior of the compounds was investigated with cyclic voltammetry, and assignments of the redox processes were carried out with the aid of density functional theory calculations. The synthesized compounds and demonstrated transformations represent useful tools for preparation of materials for charge-transport studies in metal-molecule-metal junctions.
- Roemer, Max,Wild, Duncan A.,Sobolev, Alexandre N.,Skelton, Brian W.,Nealon, Gareth L.,Piggott, Matthew J.,Koutsantonis, George A.
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p. 3789 - 3799
(2019/03/17)
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- Chemoenzymatic Total Synthesis of ent-Oxycodone: Second-, Third-, and Fourth-Generation Strategies
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Four distinct approaches to ent-oxycodone were designed and accomplished. All rely on the same starting material, the diene diol derived from phenethyl acetate by the whole-cell fermentation with E. coli JM109 (pDTG601A), a strain that overexpresses toluene dioxygenase. The key step in the first-generation approach involves the construction of the C-9/C-14 bond by a SmI2-mediated cyclization of a keto aldehyde. The second-generation design relies on the use of the Henry reaction to accomplish this task. In both of these syntheses, Parker's cyclization was employed to construct the D-ring. The third-generation synthesis provides an improvement over the second in that the nitrogen atom at C-9 is introduced by azidation of the C-9/C-10 olefin, followed by reduction and lactam formation between the C-9 amine and the Fukuyama-type lactone. Finally, the fourth generation takes advantage of the keto-nitrone reductive coupling to generate the C-9/C-14 linkage. The four generations of the total syntheses of ent-oxycodone were accomplished in 13, 18, 16, and 11 operations (19, 23, 24, and 18 steps), respectively. Experimental and spectral data are provided for all new compounds.
- Makarova, Mariia,Endoma-Arias, Mary Ann A.,Dela Paz, Helen E.,Simionescu, Razvan,Hudlicky, Tomas
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supporting information
p. 10883 - 10904
(2019/08/27)
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- NOVEL CHIRAL DOPANT AND LIQUID CRYSTAL COMPOSITION
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PROBLEM TO BE SOLVED: To provide a cholesteric liquid crystal capable of changing a reflected color even if a low voltage is applied. SOLUTION: The invention provides a compound represented by formula (I) in the figure. [X1 and X2 each represent an oxygen atom or the like; Y represents a single bond, a substituted/unsubstituted C1-10 alkylene group, a nitrogen atom, or P(=O)-O; T represents a linking group; Fc represents ferrocene or a derivative thereof; n, s and t each represent an integer from 0 to 2, provided that one or two thereof represent 1 or 2; R1 and R2 each represent a C1-18 alkyl group; and p and q each represent an integer from 0 to 6.] SELECTED DRAWING: Figure 1 COPYRIGHT: (C)2019,JPOandINPIT
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Paragraph 0071; 0075; 0076
(2019/12/31)
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- Practical Chromatography-Free Synthesis of 2-Iodo- N, N -diiso propylferrocenecarboxamide and Further Transformations
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An efficient procedure able to deliver grams of racemic and enantioenriched 2-iodo- N, N -diisopropylferrocenecarboxamide without chromatographic purification was developed. To introduce the halogen, two procedures, one using the n BuLi-TMEDA chelate and one using a lithium amide in the presence of ZnCl 2 as in situ trap were developed. Further functionalization by Suzuki-Miyaura and Ullman-type cross-couplings was investigated to access a variety of ferrocene derivatives.
- Dorcet, Vincent,Erb, William,Roisnel, Thierry
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p. 3205 - 3213
(2019/08/28)
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- Design, synthesis and fungicidal activity studies of 3-ferrocenyl-N-acryloylmorpholine
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Ferrocene and its derivatives have been widely used in many fields and also used to modify and improve the performance. Particularly, their low toxicity also attract much attention in medical and pesticide fields. In order to get fungicides with higher biological activity, ferrocenyl groups were introduced into the skeleton of dimethomorph instead of phenyl groups and a series of 3-ferrocenyl-N-acryloylmorpholine were synthesized. The fungicidal bioassay results indicated that most of compounds showed moderate fungicidal activities against 14 kinds of agricultural pathogenic fungi and some compounds displayed higher fungicidal activities than that of dimethomorph. Intrestlingly, compounds 5(Z) exhibited better fungicidal activity against Sclerotinia sclerotiorum than that of compound 5(E).
- Chen, Peiqi,Liu, Chunjuan,Hu, Jianfeng,Zhang, Hao,Sun, Ranfeng
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p. 113 - 121
(2017/12/12)
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- Redox-Responsive Chiral Dopant for Quick Electrochemical Color Modulation of Cholesteric Liquid Crystal
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Here, we report the first redox-active chiral dopant FcD, which electrically alters its helical twisting power (HTP) for a cholesteric liquid crystalline (LC) medium and quickly changes the reflection color. FcD is composed of an axially chiral binaphthyl unit in conjunction with a redox-active ferrocene unit. A cholesteric LC phase of 4′-pentyloxy-4-cyanobiphenyl, doped with FcD (3.0 mol %), developed a blue reflection color. When nitrosyl tetrafluoroborate, a one-electron oxidant, was added to this cholesteric LC phase, FcD was oxidized to decrease its original HTP value by 13%, so that a green reflection color was developed. In the presence of a supporting electrolyte, the reflection color was electrochemically modulated using a sandwich-type glass cell with indium tin oxide electrodes. In quick response to the applied voltage of +1.5 V, the reflection color changed from blue to green within 0.4 s. When 0 V was applied, the reflection color returned to its original blue color. The FcD-doped cholesteric LC is characterized by its fastest electrochemical response and lowest operating voltage among those reported for electrically driven cholesteric LC devices.
- Tokunaga, Shoichi,Itoh, Yoshimitsu,Tanaka, Hiroyuki,Araoka, Fumito,Aida, Takuzo
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p. 10946 - 10949
(2018/09/06)
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- Ferrocenyl Janus mixed-dendron stars and their stabilization of Au and Ag nanoparticles
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Janus molecular architectures have recently attracted attention due to their structures and properties that differ from those of traditional symmetric structures. Herein, two new small redox-reversible mixed-dendron star-shape molecules containing three ferrocenyl groups have been synthesized by linking two distinct dendrons using an esterification reaction. These organometallic nano structures were characterized by 1H and 13C NMR, MS, IR and UV–vis. spectroscopies and cyclic voltammetry confirming the number of ferrocenyl groups and AFM and DLS showing micellar assemblies. Au and Ag nanoparticles were stabilized in the presence of a mixed-dendron structure having amidoferrocene termini upon reaction of the nanoparticle metal precursor with NaBH4. Compared reactions of the two star-molecules with HAuCl4 showed a slow redox reaction leading to Au nanoparticles only with the star-molecule terminated with triazolyferrocene termini, which is taken into account by the difference of their redox potentials.
- Liu, Yue,Mu, Shengdong,Liu, Xiong,Ling, Qiangjun,Hang, Chaodong,Ruiz, Jaime,Astruc, Didier,Gu, Haibin
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p. 4777 - 4789
(2018/07/31)
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- Ferrocenecarboxylic acid and microwave-assisted synthesis of ferrocenoyl hydrazones
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A protocol to access ferrocenecarboxylic acid via carboxylation of ferrocene with carbon dioxide in the presence of aluminum chloride was elaborated. An efficient microwave-assisted synthesis of ferrocenoyl hydrazones by condensation of ferrocene carbohydrazide with carbonyl compounds was developed. Structures of the synthesized compounds were examined by NMR spectroscopy and mass spectrometry. Structures of N′-(4-chlorobenzylidene)ferrocenecarbohydrazide, N′-(4-methoxybenzylidene)ferrocenecarbohydrazide, and N′-(2-hydroxybenzylidene)ferrocenecarbohydrazide were determined by X-ray diffraction analysis. Synthesized compounds were found to have no toxicity against P. aeruginosa, E. coli, S. aureus, B. subtilis, M. rubrum, and C. albicans.
- Kulikov,Nikulin,Arkhipov,Rodionov,Babusenko,Kovalenko,Belousov, Yu. A.
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p. 537 - 544
(2017/09/15)
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- Synthesis and in vitro Biological Evaluation of Ferrocenyl Side-Chain-Functionalized Paclitaxel Derivatives
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Taxanes, including paclitaxel, are widely used in cancer therapy. In an attempt to overcome some of the disadvantages entailed with taxane chemotherapy, we devised the synthesis of ferrocenyl-functionalized paclitaxel derivatives and studied their biological properties. The cytotoxic activity was measured with a panel of human cancer cell lines of various tissue origin, including multidrug-resistant lines. A structure–activity study of paclitaxel ferrocenylation revealed the N-benzoyl-ferrocenyl-substituted derivative to be the most cytotoxic. In contrast, substitution of the 3′-phenyl group of paclitaxel with a ferrocenyl moiety led to less potent antiproliferative compounds. However, these agents were able to overcome multidrug resistance, as they were virtually unrecognized by ABCB1, a major cellular exporter of taxanes. Interestingly, the redox properties of these ferrocenyl derivatives appear to play a less important role in their mode of action, as there was no correlation between intracellular redox activity and cytotoxicity/cell-cycle distribution. The antiproliferative activity of ferrocenyl taxanes strongly depends on the substitution position, and good tubulin polymerization inducers, as confirmed by molecular docking, were usually more cytotoxic, whereas compounds with stronger pro-oxidative properties exhibited lower antiproliferative activity.
- Pla?uk, Damian,Wieczorek, Anna,Ciszewski, Wojciech M.,Kowalczyk, Karolina,B?au?, Andrzej,Pawl?dzio, Sylwia,Makal, Anna,Eurtivong, Chatchakorn,Arabshahi, Homayon J.,Reynisson, Jóhannes,Hartinger, Christian G.,Rychlik, B?a?ej
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p. 1882 - 1892
(2017/11/10)
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- Borylation, silylation and selenation of C-H bonds in metal sandwich compounds by applying a directing group strategy
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Palladium-mediated borylation, silylation, and selenation have been achieved by C-H activation using bidentate directing groups linked on iron and cobalt sandwich compounds. Herein, the first examples of borylation and silylation using pyridine-N-oxide and (2-methylthio)phenyl directing groups have been shown using Pd(OAc)2 as a catalyst. In the case of C-H selenation, the product was formed by treating diphenyl-diselenide with an 8-aminoquinoline-based palladacycle. The novel palladacycle intermediates of the C-B, C-Si, and C-Se bond formation have been isolated and structurally characterized. A correlation between the type of heteroatom added and the donor atom of the installed bi-dentate directing group has also been presented.
- Deb, Mayukh,Singh, Jatinder,Mallik, Shuvadip,Hazra, Susanta,Elias, Anil J.
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supporting information
p. 14528 - 14538
(2017/11/28)
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- From 2- to 3-Substituted Ferrocene Carboxamides or How to Apply Halogen dance to the Ferrocene Series
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Two methods were compared to convert ferrocene into N,N-diisopropylferrocenecarboxamide, N,N-diethylferrocenecarboxamide, N,N-dimethylferrocenecarboxamide, and (4-morpholinocarbonyl)ferrocene, namely, deprotometalation followed by trapping using dialkylcarbamoyl chlorides and amide formation from the intermediate carboxylic acid. The four ferrocenecarboxamides were functionalized at C2 in the case of the less hindered and more sensitive amides, recourse to a mixed lithium-zinc 2,2,6,6-tetramethylpiperidino-based base allowed us to achieve the reactions. Halogen migration using lithium amides was next optimized. Whereas it appeared impossible to isolate the less hindered 3-iodoferrocenecarboxamides, 3-iodo-N,N-diisopropylferrocenecarboxamide proved stable and was converted to new 1,3-disubstituted ferrocenes by Suzuki coupling or amide reduction. DFT calculations were used to rationalize the results obtained.
- Tazi, Mehdi,Erb, William,Halauko, Yury S.,Ivashkevich, Oleg A.,Matulis, Vadim E.,Roisnel, Thierry,Dorcet, Vincent,Mongin, Florence
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supporting information
p. 4770 - 4778
(2018/02/07)
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- Ferrocene - quinolone amide compound and its preparation method and application
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The invention discloses a series of ferrocene-quinolone amide compounds as well as a preparation method and application thereof. The preparation method comprises the following steps: 1) selecting quinolone bulk drug according to a target compound to be prepared, placing the selected quinolone bulk drug and methyl alcohol in a reactor to be subjected to reflux reaction, adjusting the pH of the reaction liquid to be 8-10, then, extracting by using an extraction agent, collecting an organic phase, and removing the solvent through evaporation, so as to obtain corresponding floxacin methyl ester; 2) taking the floxacin methyl ester and triethylamine, placing the floxacin methyl ester and triethylamine in a first organic solvent, and adding chlorocarbonyl ferrocene for reaction under the protection of inert gas, and performing suction filtration, so as to obtain an intermediate body; 3) taking the intermediate body and an alkaline substance, dissolving the intermediate body and the alkaline substance with a second organic solvent, performing reflux reaction, adjusting the pH of the reaction liquid to be 1-4, filtering, and collecting sediments, so as to obtain the target compound. The compound provided by the invention has obvious inhibiting effect on certain bacteria, and is expected to be used for preparing antibacterial drug.
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Paragraph 0022; 0039-0040
(2018/11/04)
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- Evolution of a Polyene Cyclization Cascade for the Total Synthesis of (?)-Cyclosmenospongine
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We report a full account on the development of a unique cationic polyene cyclization for the total synthesis of the tetracyclic meroterpenoid (?)-cyclosmenospongine. A highly convergent three-component coupling strategy enabled rapid access to individual cyclization precursors that were tested for their reactivity. The successful transformation generates three rings and sets four consecutive stereocenters in a single operation proceeding in a highly efficient manner to give exclusively the trans-decalin framework. In addition, we found that the enol ether geometry and the relative configuration of C3 and C8 are crucial for the success of the polyene cyclization.
- Speck, Klaus,Magauer, Thomas
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supporting information
p. 1157 - 1165
(2017/02/05)
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- Construction of Redox Responsive Vesicles Based on a Supra-Amphiphile for Enzyme Confinement
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Redox responsive vesicles were constructed based on self-assembly of a supra-amphiphile built by the host- guest interaction between β-cyclodextrin and a ferrocene derivative. The structure and destruction-reconstruction reversibility of the “smart” vesicles were clearly characterized by electron microscopy and dynamic light scattering. Notably, these vesicles were proved to be capable of controlled release function and bringing protease resistance to the enzyme, showing great biocompatibility and promising applications.
- Pan, Tiezheng,Zou, Huixin,Sun, Hongcheng,Liu, Yao,Liu, Shengda,Luo, Quan,Dong, Zeyuan,Xu, Jiayun,Liu, Junqiu
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supporting information
p. 871 - 875
(2017/06/27)
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- Intramolecular Direct C-H Arylation via a Metallocenic Radical Pathway: Stereospecific Approach to Planar-Chiral Ferrocenes
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Transition metal-free synthesis of planar-chiral 1,2-fused ferrocenes via intramolecular direct C-H bond arylation was achieved. The C-H arylation reactions promoted by a catalytic amount of 1,10-phenanthroline highlighted a unique planar-chiral metallocenic radical intermediate, generated from iodoferrocenes via a single-electron transfer process.
- Liu, Yang,Xu, Jiancong,Zhang, Jinling,Xu, Xiaohua,Jin, Zhong
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p. 5709 - 5712
(2017/10/25)
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- Enantioselective Palladium-Catalyzed Intramolecular α-Arylative Desymmetrization of 1,3-Diketones
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An efficient enantioselective protocol has been reported to build highly oxygenated and densely substituted bicyclo[m.n.1] skeletons through intramolecular asymmetric α-arylative desymmetrization of 1,3-diketones. Employing Pd catalyst and FOXAP ligand, various bicyclo[m.n.1] skeleton with different size can be accessed with high enantio- and diastereoselectivities. Utilizing the present method as a key step, formal asymmetric total synthesis of the (-)-parvifoline has been demonstrated.
- Zhu, Chendan,Wang, Dingyi,Zhao, Yue,Sun, Wei-Yin,Shi, Zhuangzhi
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supporting information
p. 16486 - 16489
(2017/11/30)
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- Ferrocene-based polyethyleneimines for burning rate catalysts
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Ferrocene-based polymers and their derivatives have the ability to catalyze the burning process of composite solid propellants efficiently. However, the simple and volatile ferrocene migrates to the surface of the solid propellant on prolonged storage, wh
- Zain-Ul-Abdin,Wang, Li,Yu, Haojie,Saleem, Muhammad,Akram, Muhammad,Abbasi, Nasir M.,Khalid, Hamad,Sun, Ruoli,Chen, Yongsheng
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p. 3155 - 3163
(2016/05/09)
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- Synthesis of MeO-PEG2000-supported chiral ferrocenyl oxazoline carbinol ligand and its application in asymmetric catalysis
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A simple method for the synthesis of a MeO-PEG-supported chiral ferrocenyl oxazoline carbinol ligand has been developed. The chiral ligand was successfully applied to the catalytic asymmetric addition of diethylzinc to aryl aldehydes, affording secondary alcohols in high yields and with excellent enantioselectivities (up to 94% ee). The chiral ligand can be recovered and reused twice with no apparent loss of catalyst efficiency.
- Zhao, Wen-Xian,Liu, Guan-Jun,Wang, Jingjing,Li, Feng,Liu, Lantao
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p. 1133 - 1144
(2016/11/11)
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- Chiral and Redox-Active Room-Temperature Ionic Liquids Based on Ferrocene and l-Proline
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The syntheses of room-temperature ionic liquids (RTILs) combining the naturally occurring amino acid l-proline and ferrocene (Fc) building blocks are reported. After quaternization of ({[(2S)-N-methylpyrrolidine-2-yl]methyleneoxy}carbonyl)ferrocene (1) with alkyl iodides and anion exchange, the resulting diastereomeric (1S,2S)- and (1R,2S)-[(ferrocenylcarbonyl)oxy]methylene-N,N-dialkylpyrrolidine-1-ium RTILs are redox-active and air- and water-stable. They are also thermally stable up to 263 °C. The electrochemical FeII/FeIIIpotential is shifted to +0.28 V versus Fc/Fc+. Before anion exchange, several iodide derivatives were obtained as crystalline products, and their crystal structures are reported. According to the NMR spectroscopic data cation–anion aggregates are present in the non-coordinating solvent CDCl3. In contrast, in the polar solvent [D6]dimethyl sulfoxide ([D6]DMSO), the ion pairs are separated.
- Bouvet, Carola B.,Krautscheid, Harald
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supporting information
p. 4573 - 4580
(2016/10/11)
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- Expedient Iron-Catalyzed C-H Allylation/Alkylation by Triazole Assistance with Ample Scope
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Triazole assistance set the stage for a unified strategy for the iron-catalyzed C-H allylation of arenes, heteroarenes, and alkenes with ample scope. The versatile catalyst also proved competent for site-selective methylation, benzylation, and alkylation with challenging primary and secondary halides. Triazole-assisted C-H activation proceeded chemo-, site-, and diastereo-selectively, and the modular TAM directing group was readily removed in a traceless fashion under exceedingly mild reaction conditions. One for all: A unified strategy for iron-catalyzed C-H allylation and alkylation was developed by the use of a triazole directing group that could be cleaved under exceedingly mild conditions.
- Cera, Gianpiero,Haven, Tobias,Ackermann, Lutz
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supporting information
p. 1484 - 1488
(2016/02/12)
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