- Methylenespiro[2.3]hexanes via Nickel-Catalyzed Cyclopropanations with [1.1.1]Propellane
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[1.1.1]Propellane is a highly strained tricyclic hydrocarbon whose reactivity is dominated by addition reactions across the central inverted bond to provide bicyclo[1.1.1]pentane derivatives. These reactions proceed under both radical and two-electron pathways, hence, providing access to a diverse array of products. Conversely, transition metal-catalyzed reactions of [1.1.1]propellane are underdeveloped and lack synthetic utility, with reported examples generally yielding mixtures of ring-opened structural isomers, dimers, and trimers, often with poor selectivity. Herein, we report that nickel(0) catalysis enables the use of [1.1.1]propellane as a carbene precursor in cyclopropanations of a range of functionalized alkenes to give methylenespiro[2.3]hexane products. Computational studies provide support for initial formation of a Ni(0)-[1.1.1]propellane complex followed by concerted double C-C bond activation to give the key 3-methylenecyclobutylidene-nickel intermediate.
- Yu, Songjie,Noble, Adam,Bedford, Robin B.,Aggarwal, Varinder K.
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- A versatile electrochemical sensing receptor based on a molecularly imprinted polymer
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Electrochemical molecularly imprinted polymers (e-MIPs) are reported for the first time. Their elaboration is based on the introduction of a redox tracer (vinylferrocene) inside the binding cavities of a cross-linked MIP. Determination of the analyte (benzo[a]pyrene) can be simply performed by measuring the redox tracer signal. the Partner Organisations 2014.
- Udomsap, Dutduan,Branger, Catherine,Culioli, Gérald,Dollet, Pascal,Brisset, Hugues
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- Synthesis and Characterization of a Family of Air-Stable Ferrocene- and Ruthenocene-Containing Primary, Secondary, and Tertiary Phosphines
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The synthesis and characterization of a family of air-stable primary, secondary, and tertiary phosphines containing all possible combinations of ethylferrocene and ethylruthenocene substituents are reported. Each phosphine was characterized by 1H, 13C, and 31P NMR spectroscopy, IR and UV-vis absorption spectroscopy, mass spectrometry, and elemental analysis. With the exception of primary ethylruthenocene phosphine 8a, all of the title compounds have been studied by single-crystal X-ray crystallography. Ferrocene-containing phosphines showed maximum absorption at wavelengths of ca. 440 nm and qualitatively reversible oxidation waves in their cyclic voltammograms with intensities scaling to the number of ferrocene units present. The average metal-cyclopentadienyl centroid distances observed for ferrocene-containing phosphines were shorter than those of ruthenocene-containing phosphines, which also had maximum absorption wavelengths of ca. 320 nm and underwent irreversible electrochemical oxidation. Phosphines containing both ethylferrocene and ethylruthenocene substituents displayed properties consistent with the presence of both metallocene types.
- Kenaree, Amir Rabiee,Cuthbert, Tyler J.,Barbon, Stephanie M.,Boyle, Paul D.,Gillies, Elizabeth R.,Ragogna, Paul J.,Gilroy, Joe B.
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- Reactions of Cp2TiMe2 with ferrocene and (n5-Cp)Co(n4-C4Ph4) derived esters and amides: A new route for 1-methylvinyl and methyl ketone derived metal sandwich compounds
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Reactions of Cp2TiMe2, with the ester derivatives of organometallic sandwich compounds (n5-RC5H4)Fe(n5-C5H5) and (n5-RC5H4)Co(n4-C4Ph4) (R=ester groups) gave products having R=C(CH2)Me, instead of the expected vinyl ethers indicating conversion of the ester units by Cp2TiMe2 to methyl ketones followed by methylenation. A reaction of Cp2TiMe2 with the diester (n5-RC5H4)Co(n4-C4Ph3R)(R=C(O)OMe) also gave similar results. The study has also been successfully extended to metal sandwich derived amides, thio and seleno esters. By controlling the amount of Cp2TiMe2, the reactions were also stopped at the methyl ketone stage and the methyl ketones were isolated in good yields and characterized. The method provides an easy and direct access to convert organometallic sandwich derived esters and related compounds to 1-methylvinyl derived products.
- Singh, Jatinder,Ghosh, Sanjib,Deb, Mayukh,Elias, Anil J.
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- Synthesis, characterization and second-order nonlinear optical behaviour of ferrocene-diketopyrrolopyrrole dyads: The effect of alkene: Vs. alkyne linkers
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New, thermally stable dipolar ferrocene-diketopyrrolopyrrole (Fc-DPP) dyads with alkene as a linker exhibited structure dependent first hyperpolarizabilities, βHRS, recorded by a femtosecond HRS technique using a femtosecond (120 fs) pulsed laser light system at 900 nm at ambient temperature. On the basis of linear optical, electrochemical and TD-DFT studies, a good structure-polarization relationship has been established to account for the observed trends in first hyperpolarizabilities. The dyads exhibited fluctuating but matching solvatochromism. Nonlinear optical properties are modulated both by the strength of the acceptor as well as the length and nature of the π-conjugation bridge. βHRS of the dyads were compared with structurally related dyads in which the DPP core and the Fc donor are linked via an alkyne bridge. It is interesting to observe that the replacement of an alkyne link with alkene in these D-π-A chromophores does not necessarily furnish enhanced βHRS.
- Kaur, Sarbjeet,Van Steerteghem, Nick,Kaur, Paramjit,Clays, Koen,Singh, Kamaljit
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- Pd-catalyzed rearrangement of ferrocenylalkyl vinyl ethers to the related aldehydes and ketones
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Ferrocenylalkyl vinyl ethers undergo a facile rearrangement (CH2Cl2, 20–25 °C, 0.5 h) in the presence of 3–4 mol% PdCl2(MeCN)2, to give the corresponding ferrocenyl alkanals or alkanones in high yields. Yttrium and lanthanide triflates and Lewis acids (AlCl3) were less effective as catalysts.
- Kolyvanov, Nikita A.,Oparina, Ludmila A.,Tarasova, Olga A.,Albanov, Alexander I.,Gusarova, Nina K.,Trofimov, Boris A.
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- Synthesis, spectra and crystal structure of (E)-(CO)2(NO)Cr[(η5-C5H 4)-CH=CH(η5-C5H4)]Cr(CO) 2(NO)
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Compounds 1,2-bis[(η5-cyclopentadienyl)dicarbonylnitrosylchromium]ethene (7) (hereafter called 1,2-dicynichrodenylethene) and 1,2-diferrocenylethene (10) were prepared from formylcynichrodene (3) and formylferrocene (9), respectively, via the McMurry's low-valent titanium coupling method. Compounds (η5-vinylcyclopentadienyl)dicarbonylnitrosylchromium (6) and vinylferrocene (11) were obtained by the dehydration of the corresponding alcohols. The structure of 7 was solved by an X-ray diffraction study: space group, P21/c; monoclinic; a=6.379(5), b=11.295(3) and c=11.9352(24); Z=2. It turns out that compound 7 adopts a transoid conformation at the ethenylene bridge and the two cyclopentadienyl rings are coplanar. The nitrosyl group in each cynichrodenyl moiety of 7 is located at the side towards the corresponding ethenylene carbon atom with a twist angle of 46.5°. The chemical shifts of H(2)-H(5) protons and C(2)-C(5) carbon atoms of a series of vinyl derivatives of compounds bearing cyclopentadienyl rings have been assigned using two-dimensional HetCOR-NMR spectroscopy. For the derivatives of cynichrodene (1) and ferrocene, it was found that the shielding of C(2,5) and C(3,4) carbon atoms is parallel to the shielding of the ortho- and para-carbon atoms of benzene derivatives. The electron density distribution in the cyclopentadienyl ring is discussed on the basis of 13C-NMR data. Surprisingly, the vinyl group donates electron density to the adjacent cynichrodene moieties rather than withdraws from them.
- Wang, Yu-Pin,Lui, Xen-Hum,Lin, Bi-Son,Tang, Wei-Der,Lin, Tso-Shen,Liaw, Jen-Hai,Wang, Yu,Liu, Yi-Hung
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- Dynamic parallel kinetic resolution of α-ferrocenyl cation initiated by chiral Br?nsted acid catalyst
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The dynamic parallel kinetic resolution (DPKR) of an α-ferrocenyl cation intermediate under the influence of a chiral conjugate base of a chiral phosphoric acid catalyst has been demonstrated in an SN1 type substitution reaction of a racemic ferrocenyl derivative with a nitrogen nucleophile. The present method provides efficient access to a ferrocenylethylamine derivative in a highly enantioselective manner, which is potentially useful as a key precursor of chiral ligands for metal catalysis. The mechanism of the present intriguing resolution system was elucidated by control experiments using the enantio-pure precursor of relevant α-ferrocenyl cation intermediates and the hydroamination of vinylferrocene. Further theoretical studies enabled the elucidation of the origin of the stereochemical outcome as well as the efficient DPKR. The present DPKR, which opens a new frontier for kinetic resolution, involves the racemization process through the formation of vinylferrocene and the chemo-divergent parallel kinetic resolution of the enantiomeric α-ferrocenyl cations generated by the protonation/deprotonation sequence of vinylferrocene.
- Kikuchi, Jun,Korenaga, Toshinobu,Obayashi, Ren,Terada, Masahiro,Toda, Yasunori
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- Synthesis of ferrocenyl-bearing dendrimers with a resorcinarene core
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A series of ferrocenyl ended dendrons containing π-conjugated systems were obtained using Wittig and Heck reactions. The dendrons were attached to eight functionalized resorcinarenes via Williamson reaction obtaining high molecular weight dendrimers. No electronic communication between metal centers was observed by cyclic voltammetry. All the dendrimers were characterized by 1H, 13C NMR, FTIR, UV-Vis, MALDI-TOF, elemental analyses, and electrochemical studies.
- Valderrama, M.I. Reyes,García, R.A. Vázquez,Klimova,Klimova,Ortiz-Frade,García, M. Martínez
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- First-and second-generation heterometallic dendrimers containing ferrocenyl-ruthenium(II)-arene motifs: Synthesis, structure, electrochemistry, and preliminary cell proliferation studies
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Four first- and second-generation heterometallic ferrocenyl derived p-cymene-Ru(II) metallodendrimers, of general formula [DAB-PPI{(κ6-p-cymene)Ru((C7H5NO)-2-N,O)PTA(5-ferrocenylvinyl)}n][PF6/su
- Govender, Preshendren,Lemmerhirt, Heidi,Hutton, Alan T.,Therrien, Bruno,Bednarski, Patrick J.,Smith, Gregory S.
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- Solvent-free synthesis of ferrocenylethene derivatives
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Herein, we report a fast, mild, efficient and simple Wittig reaction in a dry state to get ferrocenylethene derivatives. The Z and E isomers can be separated by chromatography and many isomers are characterized for the first time.
- Liu, Wan-Yi,Xu, Qi-Hai,Ma, Yong-Xiang,Liang, Yong-Min,Dong, Ning-Li,Guan, De-Peng
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- Synthesis, structures and some chemical and electrochemical properties of E-1,2-diferrocenyl-3-methylthioprop-2-enone and its ketals
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2,3-Diferrocenyl-1-methylthiocyclopropenylium iodide reacts with water, metal alkoxides, phenolates and with alcohols in the presence of Et3N to give E-1,2-diferrocenyl-3-methylthioprop-2-enone or its ketals. Their structures were established b
- Berestneva, Tatiana Klimova,García, Marcos Martínez,Ortiz-Frade, Luis,Ortega, Simon Hernández,Toscano, Ruben A.,Klimova, Elena
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- Synthesis of ferrocenyl-containing silicone rubbers via platinum-catalyzed Si–H self-cross-linking
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Self-cross-linkable ferrocenyl-containing polymethylhydrosiloxanes were synthesized. Karstedt's catalyst and cis-[PtCl2(BnCN)2] were examined as cross-linking catalysts at room temperature for the reaction between Si–H groups of the ferrocenyl-containing polymethylhydrosiloxanes. Cis-[PtCl2(BnCN)2] is an effective catalyst that allows cross-linked ferrocenyl-containing silicones (silicone rubbers) to be obtained with no visible mechanical defects (bubbles or cracks) compared with Karstedt's catalyst. The ferrocene content of the ferrocenyl-containing silicone rubbers was found to be approximately 50?wt.% by energy-dispersive X-ray analysis. Compared with cross-linked non-modified polymethylhydrosiloxanes, the ferrocenyl-containing silicone rubbers exhibited improved tensile properties (the tensile strength increased from 0.47 to 0.75?MPa) and a 1.5–2.5 times lower cross-linking degree. The surface resistivity of the ferrocenyl-containing silicone rubbers (50?wt.% ferrocenyl units) was approximately 7 × 109?Ω/□, which was 10,000 times lower than that of pure polymethylhydrosiloxane. The obtained flexible electroactive ferrocenyl-containing silicone rubbers can potentially be applied as coatings for electronic and electrostatic-sensitive devices, interfaces, and sensors.
- Deriabin, Konstantin V.,Lobanovskaia, Ekaterina K.,Kirichenko, Sergey O.,Barshutina, Marie N.,Musienko, Pavel E.,Islamova, Regina M.
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- A Practical Three-Step Synthesis of Vinylferrocene
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An improved, short and efficient synthesis of vinylferrocene is reported. This three-step synthesis includes Friedel-Crafts acylation, reduction, and a one-pot mesylation/elimination step to afford the target compound in 62% yield over three steps.
- Plevová, Kristína,Mudráková, Brigita,?ebesta, Radovan
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- Synthesis of α-arylalkylferrocenes through cesium fluoride-promoted coupling of arylboronic acids with N-tosylhydrazones
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A cesium fluoride-promoted reductive coupling reaction of acylferrocene tosylhydrazones with arylboronic acids has been developed, producing highly substituted α-arylalkylferrocenes in moderate to excellent yields. The reaction employs anionic fluorine to facilitate the cleavage of C–B bond. The developed methodology demonstrates a wide substrate scope and high functional groups tolerance. Moreover, the α-arylalkylferrocenes compounds were also obtained on a multi-gram scale.
- Liu, Yueqiang,Ma, Xiaowei,Liu, Yan,Liu, Ping,Dai, Bin
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- Synthesis and properties of optically active ferrocenylethylindazoles
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The stereochemistry of two processes, viz., α-ferrocenylalkylation of indazole with optically active S-(+)-1-ferrocenylethanol and the thermal rearrangement of S-(+)-2-N-(ferrocenylethyl)indazole into S-(+)-1-N- (ferrocenylethyl)indazole, was studied. Bot
- Simenel,Kuzmenko, Yu. V.,Ilyin,Gumenyuk,Snegur,Nekrasov, Yu. S.
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- Wittig Olefination Using Phosphonium Ion-Pair Reagents Incorporating an Endogenous Base
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Despite common perception, the use of strong bases in Wittig chemistry is utterly unnecessary: we report a series of novel ion-pair phosphonium carboxylate reagents which are essentially "storable ylides". These reagents are straightforwardly prepared in excellent yields, and their fluxional nature permits clean olefination of a broad range of aldehydes and even hemiacetals.
- Vetter, Anna C.,Gilheany, Declan G.,Nikitin, Kirill
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supporting information
p. 1457 - 1462
(2021/03/08)
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- Carbosulfenylation of Alkenes with Organozinc Reagents and Dimethyl(methylthio)sulfonium Trifluoromethanesulfonate
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The electrophilic alkylthiolation of alkenes, initiated by dimethyl(methylthio)sulfonium salts and the subsequent addition of various heteronucleophilies has been well-established. Regarding the use of carbon nucleophiles, however, only carefully designed sp-type carbon sources have been successfully applied. We herein present our findings on the methylthiolation of alkenes with dimethyl(methylthio)sulfonium trifluoromethanesulfonate, followed by carbon-carbon bond formation in the presence of organozinc reagents, thus achieving a catalyst-free protocol toward to the carbosulfenylation of alkenes.
- Tang, Meizhong,Han, Shuxiong,Huang, Shenglan,Huang, Shenlin,Xie, Lan-Gui
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supporting information
p. 9729 - 9734
(2020/12/21)
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- Functionalization of Alkenyl C-H Bonds with D 2 O via Pd(0)/Carboxylic Acid Catalysis
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We report herein a simple catalytic method for the extensive labeling of alkenyl C-H bonds through the combination of a palladium(0) complex and a carboxylic acid in the presence of deuterium oxide. The reaction can be applied to a variety of terminal alkenes and the best results are obtained with aryl-substituted examples. This method represents a convenient approach for the preparation of extensively labeled chemicals from the cheapest and safest source of deuterium.
- Bigi, Franca,Camedda, Nicola,Cera, Gianpiero,Maestri, Giovanni,Maggi, Raimondo,Serafino, Andrea
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supporting information
p. 1762 - 1772
(2020/06/08)
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- An Interrupted Pummerer/Nickel-Catalysed Cross-Coupling Sequence
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An interrupted Pummerer/nickel-catalysed cross-coupling strategy has been developed and used in the elaboration of styrenes. The operationally simple method can be carried out as a one-pot process, involves the direct formation of stable alkenyl sulfonium salt intermediates, utilises a commercially available sulfoxide, catalyst, and ligand, operates at ambient temperature, accommodates sp-, sp2-, and sp3-hybridised organozinc coupling partners, and delivers functionalised styrene products in high yields over two steps. An interrupted Pummerer/cyclisation approach has also been used to access carbo- and heterocyclic alkenyl sulfonium salts for cross-coupling.
- Aukland, Miles H.,Talbot, Fabien J. T.,Fernández-Salas, José A.,Ball, Matthew,Pulis, Alexander P.,Procter, David J.
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supporting information
p. 9785 - 9789
(2018/07/31)
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- Interfacial charge transport studies and fabrication of high performance DSSC with ethylene cored unsymmetrical dendrimers as quasi electrolytes
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In this paper, authors focus the synthesis of conjugated unsymmetrical stilbenoid dendrimers by Heck and Horner-Wadsworth-Emmons coupling. In UV–visible absorption spectrum, the intensity of the absorption increases with increase in the generation of dendrimers. Further, bathochromic shift is observed on increasing the generation of the dendrimer from zero to first due to the greater widening of the energy gap between π-π* orbitals of the dendrimer system. Interfacial charge transport kinetics such as resistance, chemical capacitance and relaxation lifetime of the fabricated dye-sensitized solar cells (DSSC) are investigated using Nyquist and Bode phase plots by electrochemical impedance spectroscopy. Reduced electron relaxation lifetime (τe) of 1.83 ms (LiI + 7) and 1.04 ms (LiI + 8) provides efficient charge injection and thus reducing recombination process in the device. The performance of DSSC fabricated using unsymmetrical conjugated dendrimers with iodide electrolyte shows higher power conversion efficiency (PCE) than standard LiI based device. Two fold increments are achieved in PCE with first generation unsymmetrical dendrimers compared to their zeroth counterpart. The first generation unsymmetrical dendrimer 8 shows better PCE of 9.037% than all other synthesized dendrimers in the newly fabricated DSSC.
- Ravivarma, Mahalingam,Kumar, Kaliamurthy Ashok,Rajakumar, Perumal,Pandurangan, Arumugam
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p. 717 - 726
(2018/07/23)
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- Well-Defined Rhodium-Gallium Catalytic Sites in a Metal-Organic Framework: Promoter-Controlled Selectivity in Alkyne Semihydrogenation to E-Alkenes
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Promoters are ubiquitous in industrial heterogeneous catalysts. The wider roles of promoters in accelerating catalysis and/or controlling selectivity are, however, not well understood. A model system has been developed where a heterobimetallic active site comprising an active metal (Rh) and a promoter ion (Ga) is preassembled and delivered onto a metal-organic framework (MOF) support, NU-1000. The Rh-Ga sites in NU-1000 selectively catalyze the hydrogenation of acyclic alkynes to E-alkenes. The overall stereoselectivity is complementary to the well-known Lindlar's catalyst, which generates Z-alkenes. The role of the Ga in promoting this unusual selectivity is evidenced by the lack of semihydrogenation selectivity when Ga is absent and only Rh is present in the active site.
- Desai, Sai Puneet,Ye, Jingyun,Zheng, Jian,Ferrandon, Magali S.,Webber, Thomas E.,Platero-Prats, Ana E.,Duan, Jiaxin,Garcia-Holley, Paula,Camaioni, Donald M.,Chapman, Karena W.,Delferro, Massimiliano,Farha, Omar K.,Fulton, John L.,Gagliardi, Laura,Lercher, Johannes A.,Penn, R. Lee,Stein, Andreas,Lu, Connie C.
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supporting information
p. 15309 - 15318
(2018/11/30)
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- (Planar-Chiral) Ferrocenylmethanols: From Anionic Homo Phospho-Fries Rearrangements to α-Ferrocenyl Carbenium Ions
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The reaction of FcCH2OH with chlorophosphates gave ferrocenyl phosphates FcCH2OP(O)(OR)2 [Fc = Fe(η5-C5H5)(η4-C5H4)], which readily separate into phosphate anions and ferrocenyl carbo-cations. The latter species undergoes consecutive reactions, for example, electrophilic aromatic substitutions. When nitriles, instead of alcohols, are treated with FcLi or tBuLi and chlorophosphates, chiral-pool based ferrocenylimino phosphoramidates Fc-CR=N-P(O)(OR*)2 are formed, which are promising candidates for anionic homo phospho-Fries rearrangements. Moreover, the sterically demanding chiral chlorophosphate with R* enabled oxidative couplings of the imines to form a diferrocenylazine. Similarly, the reaction of Fc–Li with 9-anthrylnitrile produced a 10-ferrocenyl-substituted product, contrary to a reaction at the C≡N functionality. A planar-chiral ortho-P(S)Ph2-functionalized ferrocenylmethanol also gave carbo-cations under acidic conditions. These species can be sulfurized in a unique way giving thio ethers, whereby the in situ formed 1,2-P(S)Ph2,CH2+ ferrocene cation acts as the sulfur and electron source. However, lowering the substrate concentration prevents sulfur migration, resulting in electrophilic substitution reactions with aromatic solvents. Planar-chiral ferrocenylmethyl thio or anisyl derivatives were applied as ligands in Pd-catalyzed Suzuki–Miyaura C,C cross-couplings for the atroposelective synthesis of hindered biaryls with up to 26 % ee at low catalyst loadings (1 mol-% Pd).
- Korb, Marcus,Mahrholdt, Julia,Lang, Heinrich
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supporting information
p. 4028 - 4048
(2017/09/20)
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- Enantiopure Ferrocene-Based Planar-Chiral Iridacycles: Stereospecific Control of Iridium-Centred Chirality
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Reaction of [IrCp?Cl2]2 with ferrocenylimines (Fc=NAr, Ar=Ph, p-MeOC6H4) results in ferrocene C-H activation and the diastereoselective synthesis of half-sandwich iridacycles of relative configuration Sp?,RIr?. Extension to (S)-2-ferrocenyl-4-(1-methylethyl)oxazoline gave highly diastereoselective control over the new elements of planar chirality and metal-based pseudo-tetrahedral chirality, to give both neutral and cationic half-sandwich iridacycles of absolute configuration Sc,Sp,RIr. Substitution reactions proceed with retention of configuration, with the planar chirality controlling the metal-centred chirality through an iron-iridium interaction in the coordinatively unsaturated cationic intermediate.
- Arthurs, Ross A.,Ismail, Muhammad,Prior, Christopher C.,Oganesyan, Vasily S.,Horton, Peter N.,Coles, Simon J.,Richards, Christopher J.
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supporting information
p. 3065 - 3072
(2016/03/23)
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- Internal adduct formation of active intramolecular C4-bridged frustrated phosphane/borane Lewis pairs
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The tetramethylene-bridged PMes2/B(C6F 5)2 frustrated Lewis pair (FLP) 8 was prepared by hydroboration of Mes2P-(CH2)2CH=CH2 with HB(C6F5)2. It is an active FLP that splits dihydrogen under mild conditions and, consequently, serves as a metal-free hydrogenation catalyst for a variety of substrates. It also reacts typically with terminal acetylenes. The C4-bridged FLP 23 was prepared by HB(C6F5)2 hydroboration of 1- dimesitylphosphino-2-vinylferrocene. It represents a rare example of a FLP where the equilibrium between the open form and the closed internal P/B adduct form is experimentally observable. It also shows a variety of typical FLP reactions, including dihydrogen splitting. The FLPs 8 and 23 (open form) and many precursors and products were characterized by X-ray diffraction.
- Wang, Xiaowu,Kehr, Gerald,Daniliuc, Constantin G.,Erker, Gerhard
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supporting information
p. 3293 - 3303
(2014/03/21)
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- Facile regio- and stereoselective hydrometalation of alkynes with a combination of carboxylic acids and group 10 transition metal complexes: Selective hydrogenation of alkynes with formic acid
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A facile, highly stereo- and regioselective hydrometalation of alkynes generating alkenylmetal complex is disclosed for the first time from a reaction of alkyne, carboxylic acid, and a zerovalent group 10 transition metal complex M(PEt3)4 (M = Ni, Pd, Pt). A mechanistic study showed that the hydrometalation does not proceed via the reaction of alkyne with a hydridometal generated by the protonation of a carboxylic acid with Pt(PEt 3)4, but proceeds via a reaction of an alkyne coordinate metal complex with the acid. This finding clarifies the long proposed reaction mechanism that operates via the generation of an alkenylpalladium intermediate and subsequent transformation of this complex in a variety of reactions catalyzed by a combination of Bronsted acid and Pd(0) complex. This finding also leads to the disclosure of an unprecedented reduction of alkynes with formic acid that can selectively produce cis-, trans-alkenes and alkanes by slightly tuning the conditions.
- Shen, Ruwei,Chen, Tieqiao,Zhao, Yalei,Qiu, Renhua,Zhou, Yongbo,Yin, Shuangfeng,Wang, Xiangbo,Goto, Midori,Han, Li-Biao
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p. 17037 - 17044
(2011/12/04)
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- Deamination of 1-aminoethylferrocene and the crystal structure of ethenylferrocene
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Ethenylferrocene, C12H12Fe, was an unexpected product of the thermolysis of 1-aminoethylferrocene in a melt reaction with naphthalene-2,3-dicarboxylic acid. It was characterized by single crystal X-ray diffraction which revealed that the cyclopentadiene rings are slightly staggered and the ethenyl substituent lies approximately in the plane of the substituted cyclopentadiene ring. In the crystal structure C-H?π interactions link molecules into parallel rows.
- McAdam, C. John,Robinson, Brian H.,Simpson, Jim
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p. 2172 - 2175
(2009/01/30)
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- Synthesis and properties of ferrocenylalkyl derivatives of indazole
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Ferrocenylmethylation and α-ferrocenylethylation of indazole were carried out for the first time. Both reactions afforded two isomers, which were characterized by physical and physicochemical methods, among them by X-ray diffraction analysis. 1-(α-Ferroce
- Gumenyuk,Starikova,Nekrasov,Babin
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p. 1894 - 1899
(2007/10/03)
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- Efficient regio- and diastereo-controlled synthesis of 1,1′- and 1,1′,2,2′-functionalised ferrocenes and the formation of 2-oxa[3]ferrocenophanes
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The synthesis of a C2 symmetric 1,1′ ,2,2′-tetrasubstituted ferrocene system was discussed. The route involved the reduction of ferrocenyl carbonyl compounds which gave access to a range of alcohols, alkenes, alkanes, ethers, and 2-oxa[3]ferrocenophanes depending on the precise conditions used. The loss of optical activity of 1,1′-bis(hydroxymethyl)ferrocenes and 1,1′-bis(hydroxymethyl)ruthenocenes, which had been prepared by asymmetric reduction, was demonstrated in an acidic medium by extensive 1H NMR studies.
- Carroll, Michael A.,White, Andrew J.P.,Widdowson, David A.,Williams, David J.
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p. 1551 - 1557
(2008/10/08)
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- The Wittig reaction in the generation of organometallic compounds containing alkenes as side groups
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The Wittig reaction has been identified as a viable route to transition metal monomers.It has been used to synthesize (η5-C5>Mn(CO)3 from acetylcymantrene and the appropriate phosphorane at room temperature. 5-C5H4>(η5-C5H5)Fe 5-C5(CH=CRR')H4>(η5-C5H5)Fe have been produced from formylferrocene and phosphorane in refluxing benzene.E/Z isomeric ratios were identified for alkenylcymantrenes and are consistent with past Wittig studies.The aldol reaction has been identified as a side route in the Wittig reactions of acetylferrocene and phosphoranes.Carbomethoxyphosphoranes did not produce alkenes at room temperature with nonpolar solvents.
- Miller, Edward J.,Weigelt, Carolyn A.,Serth, Judith A.,Rusyid, Rusydi,Brenner, Jeffery,et al.
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- The reactions of α-phenyl- and α-ferrocenylcarbinols with diiron nonacarbonyl
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Diiron nonacarbonyl oxidized a series of α-phenylcarbinols to their corresponding aldehydes and ketones.In addition, this resagent converted 4-methoxybenzyl alcohol to 4-methoxybenzyl ether, albeit in low yield.Under the same reaction conditions, oxidation was a minor with a group of α-ferrocenylcarbinols as ether synthesis was the major reaction with those substrates which could not dehydrate; however, stereoselective olefin synthesis predominated when elimination was possible.
- Bankston, D.
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p. 129 - 138
(2007/10/02)
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