- Fine-tuning hydroxylamines as single-nitrogen sources for Pd(0)-catalyzed diamination of o-bromo(or chloro)-biaryls
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Transition metal-catalyzed diamination by hydroxylamines is a common approach for making three-membered aziridines, while its use for building the larger N-heterocycles is still underdeveloped. Herein, we report an efficient Pd(0)-catalyzed inter-molecular [4+1] annulation of o-bromo(or chloro)-biaryls with bifunctional secondary hydroxylamines for the one-step assembly of synthetically useful carbazoles. Noteworthily, a linchpin for this domino reaction was the judicious selection of both the amino-sources and Pd(0)-catalysts for enabling the prerequisite oxidative addition of aryl halides to Pd(0)-species in the presence of hydroxylamines with a labile N-O bond. [Figure not available: see fulltext.].
- Bai, Jiaxing,Ding, Pin,Han, Lingbo,Liu, Jingjing,Luan, Xinjun
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- Zirconium-redox-shuttled cross-electrophile coupling of aromatic and heteroaromatic halides
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Transition metal-catalyzed cross-electrophile coupling (XEC) is a powerful tool for forging C(sp2)–C(sp2) bonds in biaryl molecules from abundant aromatic halides. While the synthesis of unsymmetrical biaryl compounds through multimetallic XEC is of high synthetic value, the selective XEC of two heteroaromatic halides remains elusive and challenging. Herein, we report a homogeneous XEC method, which relies on a zirconaaziridine complex as a shuttle for dual palladium-catalyzed processes. The zirconaaziridine-mediated palladium (ZAPd)-catalyzed reaction shows excellent compatibility with various functional groups and diverse heteroaromatic scaffolds. In accord with density functional theory (DFT) calculations, a redox transmetallation between the oxidative addition product and the zirconaaziridine is proposed as the crucial elementary step. Thus, cross-coupling selectivity using a single transition metal catalyst is controlled by the relative rate of oxidative addition of Pd(0) into the aromatic halide. Overall, the concept of a combined reducing and transmetallating agent offers opportunities for the development of transition metal reductive coupling catalysis.
- Fu, Yue,Liu, Fang-Jie,Liu, Peng,Tang, Jian-Tao,Toste, F. Dean,Wu, Ting-Feng,Ye, Baihua,Zhang, Yue-Jiao
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supporting information
p. 1963 - 1974
(2021/07/07)
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- Self-assembly of catalytically active supramolecular coordination compounds within metal?organic frameworks
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Supramolecular coordination compounds (SCCs) represent the power of coordination chemistry methodologies to self-assemble discrete architectures with targeted properties. SCCs are generally synthesized in solution, with isolated fully coordinated metal atoms as structural nodes, thus severely limited as metal-based catalysts. Metal?organic frameworks (MOFs) show unique features to act as chemical nanoreactors for the in situ synthesis and stabilization of otherwise not accessible functional species. Here, we present the self-assembly of PdII SCCs within the confined space of a pre-formed MOF (SCCs@MOF) and its post-assembly metalation to give a PdII?AuIII supramolecular assembly, crystallography underpinned. These SCCs@MOFs catalyze the coupling of boronic acids and/or alkynes, representative multi-site metal-catalyzed reactions in which traditional SCCs tend to decompose, and retain their structural integrity as a consequence of the synergetic hybridization between SCCs and MOFs. These results open new avenues in both the synthesis of novel SCCs and their use in heterogeneous metal-based supramolecular catalysis.
- Adam, Rosa,Mon, Marta,Greco, Rossella,Kalinke, Lucas H.G.,Vidal-Moya, Alejandro,Fernandez, Antonio,Winpenny, Richard E.P.,Domenech-Carbo, Antonio,Leyva-Perez, Antonio,Armentano, Donatella,Pardo, Emilio,Ferrando-Soria, Jesus
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supporting information
p. 10350 - 10360
(2019/08/20)
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- Self-Assembly of Catalytically Active Supramolecular Coordination Compounds within Metal-Organic Frameworks
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Supramolecular coordination compounds (SCCs) represent the power of coordination chemistry methodologies to self-assemble discrete architectures with targeted properties. SCCs are generally synthesized in solution, with isolated fully coordinated metal atoms as structural nodes, thus severely limited as metal-based catalysts. Metal-organic frameworks (MOFs) show unique features to act as chemical nanoreactors for the in situ synthesis and stabilization of otherwise not accessible functional species. Here, we present the self-assembly of PdII SCCs within the confined space of a pre-formed MOF (SCCs?MOF) and its post-assembly metalation to give a PdII-AuIII supramolecular assembly, crystallography underpinned. These SCCs?MOFs catalyze the coupling of boronic acids and/or alkynes, representative multi-site metal-catalyzed reactions in which traditional SCCs tend to decompose, and retain their structural integrity as a consequence of the synergetic hybridization between SCCs and MOFs. These results open new avenues in both the synthesis of novel SCCs and their use in heterogeneous metal-based supramolecular catalysis.
- Adam, Rosa,Mon, Marta,Greco, Rossella,Kalinke, Lucas H. G.,Vidal-Moya, Alejandro,Fernandez, Antonio,Winpenny, Richard E. P.,Doménech-Carbó, Antonio,Leyva-Pérez, Antonio,Armentano, Donatella,Pardo, Emilio,Ferrando-Soria, Jesús
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supporting information
p. 10350 - 10360
(2019/08/27)
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- Aerobic and Ligand-Free Manganese-Catalyzed Homocoupling of Arenes or Aryl Halides via in Situ Formation of Aryllithiums
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Ligand-free manganese-catalyzed homocoupling of arenes or aryl halides can be carried out under aerobic conditions via the in situ formation of the corresponding aryllithiums. A wide range of biaryls and derivatives has been obtained, and a mechanism involving monomeric manganese-oxo complexes has been proposed on the basis of DFT calculations.
- Liu, Yujia,Bergès, Julien,Zaid, Yassir,Chahdi, Fouad Ouazzani,Van Der Lee, Arie,Harakat, Dominique,Clot, Eric,Jaroschik, Florian,Taillefer, Marc
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p. 4413 - 4420
(2019/03/26)
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- Acid-catalyzed rearrangements in arenes: Interconversions in the quaterphenyl series
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Arenes undergo rearrangement of phenyl, alkyl, halogen and other groups through the intermediacy of ipso arenium ions in which a proton is attached at the same carbon as the migrating substituent. Interconversions among the six quaterphenyl isomers have b
- Skraba-Joiner, Sarah L.,Holt, Carter J.,Johnson, Richard P.
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p. 2655 - 2663
(2019/12/11)
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- Desulfurization of dibenzothiophene and dibenzothiophene sulfone via Suzuki–Miyaura type reaction: Direct access to o-terphenyls and polyphenyl derivatives
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The reactivity of dibenzothiophene (DBT) or dibenzothiophene sulfone (DBTO2) with a variety of phenylboronic acids was mediated by the nickel precursor [Ni(dippe)Cl2] in the presence of a base. The reaction was performed under relatively mild conditions (70–100 °C), in aqueous media. The study of the reactivity revealed the role of water as a hydrogen source and showed a competition between the desulfurization of the corresponding substrates via a hydrodesulfurization (HDS) or by a hydrodesulfurative cross-coupling (HDSCC) reaction. Furthermore, in the absence of water sulfur-free poly-phenylic compounds were obtained in good yields as a result of a Suzuki–Miyaura type reaction, being the main product in most of the cases the corresponding o-terphenyl derivative, these products are valuable building blocks in the synthesis of more complex materials.
- Gutiérrez-Ordaz, Rubén,García, Juventino J.
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p. 373 - 381
(2018/08/31)
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- Organocopper(III) spiro complexes: Synthesis, structural characterization, and redox transformation
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Reductive elimination of Cu(III) intermediates is often proposed as a key step in many coppercatalyzed or -mediated formation of C-C or C- heteroatom bonds. However, there still lacks concrete evidence on this key step, mainly because Cu(III) complexes are usually too unstable to be isolated and structurally characterized. In this work, novel organocopper(III) spiro complexes and their analogous organocopper(I) spiro complexes were synthesized and structurally characterized. Single-crystal X-ray structural analysis revealed that the spiro Cu(III) atom adopted a distorted square-planar geometry while its corresponding spiro Cu(I) atom was tetrahedrally coordinated. A redox transformation between these spiro Cu(I) and Cu(III) complexes was experimentally observed by reacting with reductants or oxidants, respectively. As concrete evidence, the organocopper(III) spiro compounds were found to form C-C bonds intramolecularly via reductive elimination.
- Liu, Liang,Zhu, Miaomiao,Yu, Hai-Tao,Zhang, Wen-Xiong,Xi, Zhenfeng
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p. 13688 - 13691
(2017/11/07)
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- Palladium-Catalyzed Double-Suzuki-Miyaura Reactions Using Cyclic Dibenziodoniums: Synthesis of o-Tetraaryls
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Palladium-catalyzed double-Suzuki-Miyaura couplings between cyclic dibenziodoniums and arylboronic acids have been developed. As such, a wide range of o-tetraaryls were synthesized in good to excellent yields of 22-94%. Furthermore, tetraphenylene was pre
- Zhang, Yanxia,Han, Jianwei,Liu, Zhen-Jiang
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p. 1317 - 1323
(2016/03/01)
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- Role of the base and control of selectivity in the suzuki-miyaura cross-coupling reaction
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The outcome of the Suzuki-Miyaura cross-coupling for the direct competition reaction between two boronic acids was evaluated under routine synthesis conditions. The reaction selectivity was found to depend on the amount of the base used, with fewer bases
- Lima, Carlos F. R. A. C.,Rodrigues, Ana S. M. C.,Silva, Vera L. M.,Silva, Artur M. S.,Santos, Luis M. N. B. F.
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p. 1291 - 1302
(2014/05/20)
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- An active, general, and long-lived palladium catalyst for cross-couplings of deactivated (hetero)aryl chlorides and bromides with arylboronic acids
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An active, general, and long-lived palladium catalyst for Suzuki-Miyaura reactions of aryl and heteroaryl chlorides deactivated by steric hindrance, electron richness, and coordinating functional groups is reported. In reactions of arylbromide bearing two o-tert-butyl substituents, C(sp3)-H arylation of the tert-butyl group, rather than the Suzuki-Miyaura reaction, proceeded in excellent yield. The key to the success of the reactions was the development of biphenylene-substituted dicyclohexylruthenocenylphosphine (CyR-Phos) as a supporting ligand.
- Hoshi, Takashi,Honma, Tomonobu,Mori, Ayako,Konishi, Maki,Sato, Tsutomu,Hagiwara, Hisahiro,Suzuki, Toshio
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p. 11513 - 11524
(2013/12/04)
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- Iron-catalyzed homocoupling of aryl halides and derivatives in the presence of alkyllithiums
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Direct synthesis of biaryl derivatives from aryl halides takes place under very mild temperature conditions by using a ligand-free iron catalytic system. The procedure, which proceeds via an in situ quantitative aryl halide exchange with alkyllithiums, allows for excellent control of the reactivity and is in line with the sustainable development. The method is also applicable to styryl and benzyl halides and to phenylacetylene.
- Toummini, Dounia,Ouazzani, Fouad,Taillefer, Marc
-
supporting information
p. 4690 - 4693
(2013/10/08)
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- Parent o-phenylene oligomers: Synthesis, conformational behavior, and characterization
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The o-phenylenes are an unusual class of conjugated polymer, defined largely by substantial steric twisting along their backbones. Consequently, they exhibit limited conjugation but also interesting conformational behavior: they have been shown to adopt well-defined helical secondary structures, both in the solid state and in solution. While several examples of functionalized o-phenylene oligomers have been reported, most of the basic properties of the parent compounds are unknown. Here we report the synthesis and characterization of the series of unsubstituted o-phenylene oligomers up to the octamer. Through a combination of NMR spectroscopy, including dynamic NMR (EXSY), and computational chemistry, we have found that these compounds adopt compact helical conformations in solution with three repeat units per turn. Although formally conjugated, the oligomers have a very short effective conjugation length of necl ≈ 4 (based on UV-vis spectra), significantly shorter than most other conjugated systems. Also, unlike other (substituted) o-phenylenes, no hypochromicity is observed in their UV-vis spectra. The fluorescence spectra of the series exhibit a systematic blue shift with increasing length. We believe this unusual property results from increased steric congestion in the longer oligomers, which are therefore less able to accommodate structural relaxation in the excited state.
- Mathew, Sanyo M.,Hartley, C. Scott
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p. 8425 - 8432
(2012/03/11)
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- Controlling the Scholl reaction
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Guidelines for the application of the Scholl reaction were developed. Labeling experiments demonstrate that the Scholl reaction fails in small, unsubstituted oligophenylenes (e.g., o-terphenyl) due to oligomerization of the products (e.g., triphenylene). Incorporation of suitably placed blocking groups (e.g., t-butyl) suppresses oligomerization. The well-established directing group effects in electrophilic aromatic substitution predict the outcome of Scholl reactions of substituted substrates. Activating o,p-directing groups (e.g., MeO) direct bond formation o,p, either intramolecularly or intermolecularly. Deactivating o,p-directing groups (e.g., Br) also direct bond formation o,p but yields are lower. Deactivating m-directors (e.g., NO2) suppress reaction. MoCl5 and PhI(OOCCF3)2/BF 3·Et2O are general and effective reagents for the Scholl oxidation. Calculations (B3LYP/6-31G(d)) predict the Scholl reaction in alkoxyarenes to proceed via arenium cations, not radical cations. Suzuki-Miyaura couplings were used to generate 12 substituted o-terphenyl derivatives.
- King, Benjamin T.,Kroulik, Jiri,Robertson, Charles R.,Rempala, Pawel,Hilton, Cameron L.,Korinek, Justin D.,Gortari, Lisa M.
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p. 2279 - 2288
(2008/02/01)
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- Homocoupling of aryl halides using catalytic system of palladium and phosphite
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The palladium-catalyzed homocoupling of aryl halides was carried out using phosphite ligands. The optimized reaction conditions were Pd2(dba)3, phosphite 1, and NaOt-Bu in diglyme, and the desired homocoupling products were afforded in moderate to good yields. Copyright
- Moon, Jeongju,Nam, Hyungoog,Ju, Jinhun,Jeong, Miso,Lee, Sunwoo
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p. 1432 - 1433
(2008/03/14)
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- A Suzuki coupling based route to 2,2′-bis(2-indenyl)biphenyl derivatives
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Because of the promising performance in olefin polymerization of 2,2′-bis(2-indenyldiyl)biphenyl zirconium dichloride, we developed a new and broadly applicable route to 2,2′-bis(2-indenyl)biphenyl derivatives. Reaction of the known 2,2′-diiodobiphenyl (26) with the new 2-indenyl boronic acid (23) did not result in the desired 2,2′-bis(2-indenyl)biphenyl (10); instead an isomer thereof, (spiro-1,1-(2,2′-biphenyl)-2-(2-indenyl)indane) (27), was obtained. It was found that compound 10 could be made via a palladium-catalyzed reaction of 2,2-biphenyldiboronic acid (31) with 2-bromoindene (21) under standard Suzuki reaction conditions. However, the yield of this reaction was low at low palladium catalyst loadings, due to a competitive hydrolysis reaction of 2,2-biphenyldiboronic acid (31). HTE techniques were used to find an economically viable protocol. Thus, use of the commercially available 1.0 molar solution of (n-Bu)4NOH in methanol with cosolvent toluene led to precipitation of the pure product in a fast and clean reaction, using only 0.7 mol % (0.35 mol % per C-C) of the expensive palladium catalyst.
- IJpeij, Edwin G.,Beijer, Felix H.,Arts, Henricus J.,Newton, Claire,De Vries, Johannes G.,Gruter, Gert-Jan M.
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p. 169 - 176
(2007/10/03)
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- Oxovanadium(V)-Induced Cross-Coupling Reaction between Two Ligands of Organozinc Compounds
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Oxovanadium(V) compounds such as VO(OEt)Cl2 serve as useful oxidants for organozinc compounds, providing the corresponding cross-coupling products derived from two ligands of organozinc compounds. In particular, triorganozincates undergo selective cross-coupling smoothly by the action of oxovanadium(V).
- Hirao, Toshikazu,Takada, Takashi,Ogawa, Akiya
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p. 1511 - 1515
(2007/10/03)
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- Reaction of tris-arylgallium(III) with water: Biaryl coupling versus Ga- C hydrolysis
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Reaction of toluene solutions of tris(aryl)gallium(III) compounds with water results in intra-molecular biaryl coupling (70% yield) and an oligomeric organogallium(III) hydroxide/oxide [Ga12O14H4(aryl)12], whereas reaction in THF with water leads to hydrolysis, formation of arylH, and for aryl = Ph the trimeric THF hydrogen bonded trimer, [Ph2Ga(μ-OH)]3 ·3THF.
- Nichols, Peter J.,Papadopoulos, Stavroula,Raston, Colin L.
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p. 1227 - 1228
(2007/10/03)
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- Syntheses and Spectral Characteristics of Seven Polyphenyls Containing Highly Branched para-Phenylene Ring(s)
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Seven polyphenyls, including four new compounds, 2,2',6'- (2) and 3,2',6'-triphenyl-p-terphenyl (3), 3',5'-diphenyl-p-quarterphenyl (4), and 2-phenyl-3'-(2-biphenylyl)-p-terphenyl (7), were synthesized by the Ullmann coupling reaction of aryl iodide(s) or by the Kharash type coupling reaction of aryl Grignard reagent with an aryl iodide catalyzed by bis(acetylacetonato)-nickel(II).Infrared spectral studies of the polyphenyls showed that the range of 730-770 cm-1, generally accepted as the position of the out-of-plane C-H bending bands of the phenyl ring, should be widened slightly to 730-786 cm-1.The high frequency bands were confirmed to be correlated closely to the overcrowding by terminal rings in the complex structures.Proton magnetic resonance spectral studies indicated that he characteristic spectral features of the branched polyphenyls were consistent with their conformational aspects deduced from stereomodels.In the ultraviolet spetcral studies the polyphenyls containing highly branched p-phenylene ring(s) showed intense K-bands or shoulders at locations very similar to those of the corresponding linear polyphenyls containing the same number of p-phenylene rings. Keywords -- Ullmannn reaction; Ni-complex-catalyzed cross-coupling; quinquephenyl; sexiphenyl; octiphenyl; IR; UV; 1H-NMR
- Fujioka, Yasuhiro,Ozasa, Shigeru,Sato, Kazumi,Ibuki, Eiichi
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-
- Regiochemistry and Stereochemistry of Nickel-Promoted, Carbon-Carbon Bond-Forming Reactions of Cyclic Sulfur Compounds
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Reaction of methylmagnesium iodide and phenylmagnesium bromide with thianaphthene, dibenzothiophenone, thianthrene, and 2,3-dihydrothiapyran in the presence of nickel dichloride have been shown to yield, regioselectively in most cases, ring-opened products in which the carbon-sulfur bonds have been replaced by carbon-carbon bonds.Stereospecific carbon-carbon bond formation has taken place in the reactions of thianaphthene and 2,3-dihydrothiapyran, the products having maintained the cis-olefin configuration of the starting sulfur compounds.Isomerization into the more stable compounds has been observed in some cases.
- Tiecco, Marcello,Tingoli, Marco,Wenkert, Ernest
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p. 3828 - 3831
(2007/10/02)
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- Syntheses and Spectral Properties of several Branched-chain Polyphenyls containing 1,2,3-Trisubstituted Ring(s)
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Nine polyphenyls, including six new compound, 3'-phenyl-o-quaterphenyl (3), 2,6-diphenyl-m- (4), 2,6-diphenyl-p-terphenyl (5), 2,6,5'-triphenyl-m-terphenyl (6), 2',2''-diphenyl-m-quaterphenyl (8), and 2'-(phenyl-d5)-m-terphenyl (9), were synthesized by the Ullmann coupling reaction of aryl iodide(s) or by the Karash-type coupling reaction of deuterated aryl Grignard reagent with aryl iodide catalyzed by bis(acetylacetonato)-nickel(II).Infrared studies of the polyphenyls showed that the range 730-770 cm-1, generally accepted as the position of the C-H out-of-plane bending bands of phenyl rings, should be widened slightly to 730-781 cm-1.The high frequency bands were found to be correlated closely to the sterically overcrowded structure of terminal rings.Proton magnetic resonance spectral studies indicated that the characteristic spectral features of the polyphenyls containing 1,2,3-trisubstituted ring(s) were fully consistent with their conformational aspects deduced from stereomodels.Ultraviolet spectral data suggeted that the most probable conformation of the highly crowded 3',6''-diphenyl-o-quaterphenyl (1) is one in which the interplanar angles of the pivot bonds between the 1,2,3-trisubstituted ring and three benzene rings are rather smaller than those of the less crowded 2'-phenyl-m-terphenyl (2).Keywords - Ullmann reaction; nickel-complex-catalyzed cross-coupling; quaterphenyl; deuterated quaterphenyl; quinquephenyl; sexiphenyl; polyphenyl; IR; UV; 1H-NMR
- Ozasa, Shigeru,Fujioka, Yasuhiro,Kikutake, Jun-ichiro,Ibuki, Eiichi
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p. 1572 - 1581
(2007/10/02)
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- Preparation and Conformational Properties of Several 1,8-Diarylnaphthalenes
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Six new 1,8-diarylnaphthalenes, each having closely held parallel aromatic rings, were synthesized by a Kharash-type Grignard cross-coupling of arylmagnesium iodide and 1,8-diiodonaphthalene in the presence of N,N'-bis(1-methyl-3-oxobutylidene)ethylenediaminatonickel(II) as a catalyst.Among them, 1,8-di(1-naphthyl)naphthalene was obtained as cis and trans rotamers, caused by the restricted rotation at the 1,8-position.Interconversion between the rotamers on heating above their melting points was confirmed by differential scanning calorimetry.The proton magnetic resonance spectral studies of the 1,8-diarylnaphthalenes indicated the presence of a face-to-face arrangement of aromatic rings in the peri-position.Two new 8,8'-diaryl-1,1'-binaphthyls, each having two sets of closely held parallel aromatic rings, were isolated as minor coupling products.Trans-trans conformations were proposed for them on the basis of their thermal behavior.Several nickel(II) complexes were found to be effective catalysts for preparative Grignard cross-coupling reaction involving closely crowded geometry.
- Ibuki, Eiichi,Ozasa, Shigeru,Fujioka, Yasuhiro,Mizutani, Hiroshi
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p. 845 - 851
(2007/10/02)
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- Cross-coupling Reaction of Aryl Grignard Reagents with Aromatic Halides catakyzed by Bis(acetylacetonato)nickel(II)
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A series of cross-coupling reactions of aryl Grignard reagents with aromatic iodides catalyzed by bis(acetylacetonato)nickel(II) was studied to establish reaction conditions under which the cross-coupling proceeded selectively and quantitatively.Under the standard conditions thus selected, the coupling reactions proceeded within a few hours by a simple procedure and gave very pure product in high yield.Thus, the Kharash-type cross-coupling reaction was found to be very useful for the synthesis of a variety of polyphenyls.With some reactants of more or less crowded geometry, the reaction resulted in rather low yields of polyphenyls.This cross-coupling was successfully applied to the synthesis of a new compound, 2,6,2',6'-tetraphenylbiphenyl, having a highly non-planar arrangement of ?-systems.
- Ibuki, Eiichi,Ozasa, Shigeru,Fujioka, Yasuhiro,Yanagihara, Yoshihiko
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p. 802 - 809
(2007/10/02)
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- Studies of Polyphenyls and Polyphenylenes. II. The Synthesis and Physical Properties of Polyphenyls Containing Para Linkage
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Twelwe linear polyphenyls, including quinque- to octiphenyl, were synthesized by the Ullmann cross-coupling reaction of iodobiphenyl with diiodobenzene or iodoterphenyl.Ultraviolet spectral studies of the polyphenyls indicated that the positions of the K-bands above ca.260 nm, regardless of the presence of o- or m-phenylene unit(s), may be considered to be an indication of the approximate number of consecutive p-phenylene units.Infrared studies also showed that the locations of strong or medium bands in the 815-850 cm-1 region may give the same information.The HMO calculations of the longest wavelength absorption bands of twenty-four polyphenyls were carried out.A comparison between the calculated and observed wavelengths gave rather good agreement, except in the cases of two compounds.The signals of the proton magnetic resonanse spectra of eighteen polyphenyls were assigned tentatively.The correlations between the arrangement of the benzene rings and the spectral patterns are discussed.
- Ozasa, Shigeru,Hatada, Noriko,Fujioka, Yasuhiro,Ibuki, Eiichi
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p. 2610 - 2617
(2007/10/02)
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- Syntheses and Physical Properties of Several Octiphenyls and a Septiphenyl
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Six symmetrical linear octiphenyls were synthesized by the Ullmann homo-coupling reaction of iodoquaterphenyl.Another satisfactory method for synthesizing octiphenyls is also described, i.e., a Kharash-type Grignard cross-coupling of biphenylylmagnesium bromide and diiodoquaterphenyl in the presence of bis(acetylacetonato)nickel(II).Moreover, m-septiphenyl was succesfully synthesized by deamination of the corresponding amino compound.Infrared studies of the polyphenyls indicated that the fine-structure bands in the regions of 770-810 and 870-915 cm-1 may be considered as indicators of the presence of consecutive m-phenylene rings, regardless of the existence of o- or p-phenylene rings.The ultraviolet spectra of the octiphenyls, which contain two kinds of linkages, showed absorption curves closely related to those of quaterphenyls corresponding to the structural units of the former compounds.The nuclear magnetic resonance spectra of the polyphenyls without an o-phenylene ring showed multiplet peaks due to the resonances of an isolated m-phenylene proton at the lowest field within a narrow region (δ 7.81-7.95).Hueckel molecular orbital calculations of the longest wavelength absorption bands of ten polyphenyls were carried out.The calculated and observed wavelengths were in rather good agreement except for the cases of three compounds.Keywords - Ullmann reaction; Ni-complex-catalyzed cross-coupling; octiphenyls; septiphenyls; IR; UV; NMR; MO; quaterphenyl derivatives; polyphenyls
- Ozasa, Shigeru,Fujioka, Yasuhiro,Fujiwara, Michiko,Ibuki, Eiichi
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p. 3210 - 3222
(2007/10/02)
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- THE SYNTHESIS AND REACTIONS OF ortho BROMOPHENYLLITHIUM
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Experimental conditions have now been developed whereby o-bromophenyl-lithium(II) may be prepared in excellent yields and used as an organometallic intermediate for the synthesis of a variety of ortho bromo substituted phenyl compounds (o-BrC6H4X).The thermal stability, decomposition products and reactions of II were studied.Reactions between II and a variety of substrates, e.g., CO2, dimethylformamide, fluorinated esters, hexafluorobenzene, and organosilicon chlorides were examined.
- Chen, Loomis S.,Chen, Grace J.,Tamborski, Christ
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p. 283 - 292
(2007/10/02)
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- New Effective Nickel(II) Catalysts for the Cross-coupling of an Aryl Grignard Reagent with Aryl Halide
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It has been found that seventeen nickel complexes of the Ni-O4, Ni-S4, Ni-O2N2, Ni-O3N3-, Ni-N4, Ni-N6, and Ni-(C5)2 types exhibit a high catalytic activity for the selective cross-coupling reaction of an aryl Grignard reagent with aryl iodide, which make possible the synthesis of unsymmetrical aromatics of a high purity and in a high yield.
- Ibuki, Eiichi,Ozasa, Shigeru,Fujioka, Yasuhiro,Okada, Motofumi,Terada, Katsutoshi
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p. 821 - 822
(2007/10/02)
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- Syntheses and Physical Properties of Several Symmetrical Sexiphenyls
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Seven sexiphenyls, including three new isomers, 3,4,3',4'-tetraphenylbiphenyl (Id), 2,5,2',5'-tetraphenylbiphenyl (IIId), and 2,2'-di(3-biphenylyl)biphenyl (Vd), were synthesized by Ullmann homo-coupling of iodoterphenyl.The characteristic band of the infrared spectra (675-920 cm-1) and signals of the nuclear magnetic resonance spectra of the sexiphenyls were assigned tentatively and are discussed briefly.Infrared studies indicated that the range 730-770 cm-1, generally accepted as the position of the C-H out-of-plane bending bands of phenyl rings, should be widened slightly to 730-782 cm-1.The ultraviolet spectra commonly displayed an intense E-band in the narrow region of 192-207 nm.The prominent K-band above ca. 260 nm of branched sexiphenyls was taken as indicative of the presence of one or more p-linkages, as in the case of linear compounds.Keywords - polyphenyls; Ullmann reaction; infrared spectra; ultraviolet spectra; NMR spectra; iodoterphenyls
- Ibuki, Eiichi,Ozasa, Shigeru,Fujioka, Yasuhiro,Kitamura, Hirohiko
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p. 1468 - 1476
(2007/10/02)
-