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941.
Alistair Boyer 《Tetrahedron》2010,66(33):6468-5861
Rhodium(I) catalysts promote the transformation of o-alkynyl phenols and anilines to the corresponding benzo[b]furans and indoles. The reaction is postulated to proceed via a transient 3-rhodium heterocycle intermediate, which can be trapped with suitable electrophiles to give poly-substituted heterocycles. In the case of mono-substituted electron-withdrawn electrophiles, excellent yield and selectivity for conjugate addition versus Heck-Mizoroki reaction can be achieved. In the case of 2-alkynyl pyridine electrophiles, novel 2-(benzofuran-3-yl)vinylpyridines are formed. 相似文献
942.
Jiayun Li Jiajian Peng Guodong Zhang Xiaonian Li 《Journal of organometallic chemistry》2010,695(3):431-2477
Phosphines with 2-imidazolium ligands can specifically vary their physical and chemical properties by altering the attached substituents. Rhodium complexes (1b-7b) exhibited excellent catalytic activity and selectivity for hydrosilylation of olefins. The selectivity of the β-adduct clearly increased when the length of the alkyl chain bound to the imidazolium cation increased. Rhodium complex 1b in BMimPF6 can be reused without noticeable loss of catalytic activity and selectivity. 相似文献
943.
The mononuclear cationic complexes [(η6-C6H6)RuCl(L)]+ (1), [(η6-p-iPrC6H4Me)RuCl(L)]+ (2), [(η5-C5H5)Ru(PPh3)(L)]+ (3), [(η5-C5Me5)Ru(PPh3)(L)]+ (4), [(η5-C5Me5)RhCl(L)]+ (5), [(η5-C5Me5)IrCl(L)]+ (6) as well as the dinuclear dicationic complexes [{(η6-C6H6)RuCl}2(L)]2+ (7), [{(η6-p-iPrC6H4Me)RuCl}2(L)]2+ (8), [{(η5-C5H5)Ru(PPh3)}2(L)]2+ (9), [{(η5-C5Me5)Ru(PPh3)}2(L)]2+ (10), [{(η5-C5Me5)RhCl}2(L)]2+ (11) and [{(η5-C5Me5)IrCl}2(L)]2+ (12) have been synthesized from 4,4′-bis(2-pyridyl-4-thiazole) (L) and the corresponding complexes [(η6-C6H6)Ru(μ-Cl)Cl]2, [(η6-p-iPrC6H4Me)Ru(μ-Cl)Cl]2, [(η5-C5H5)Ru(PPh3)2Cl)], [(η5-C5Me5)Ru(PPh3)2Cl], [(η5-C5Me5)Rh(μ-Cl)Cl]2 and [(η5-C5Me5)Ir(μ-Cl)Cl]2, respectively. All complexes were isolated as hexafluorophosphate salts and characterized by IR, NMR, mass spectrometry and UV-vis spectroscopy. The X-ray crystal structure analyses of [3]PF6, [5]PF6, [8](PF6)2 and [12](PF6)2 reveal a typical piano-stool geometry around the metal centers with a five-membered metallo-cycle in which 4,4′-bis(2-pyridyl-4-thiazole) acts as a N,N′-chelating ligand. 相似文献
944.
Sengodagounder Muthusamy Datshanamoorthy Azhagan Boopathy Gnanaprakasam Eringathodi Suresh 《Tetrahedron letters》2010,51(43):5662-5665
Reaction of cyclic diazoamides and cyclic olefins or heteroaromatic systems using copper(I) triflate as a catalyst furnished a variety of strained spiro-cyclopropanooxindoles in a diastereoselective manner under mild reaction conditions. The effect of copper(I) triflate and rhodium(II) acetate catalysts on the cyclopropanation was also studied. 相似文献
945.
Dmitry V. Muratov Pavel V. Petrovskii Gerhard E. Herberich 《Journal of organometallic chemistry》2006,691(15):3251-3259
Triple-decker complexes with a bridging borole ligand (C4H4BPh)Rh(μ-C4H4BPh)ML (ML = RuCp, 2a; RuCp∗, 2b; FeCp∗, 3; Co(C4Me4), 4; Ir(cod), 5) were synthesized by stacking reactions of [Rh(C4H4BPh)2]− (1) with cationic [ML]+ fragments. The structures of 2a,b and (C4H4BPh)Rh(μ-C4H4BPh)Rh(C4H4BPh) (6) were determined by X-ray diffraction. 相似文献
946.
A novel Rh(I)-catalyzed cascade reaction was developed by combination of a hydroacylation of 4,6-dienal and a cycloisomerization of the resultant triene, giving the bicyclo[5.3.0]decenone derivative 8b in a stereoselective manner. It was found that the Thorpe-Ingold effect played an important role in the second cycloisomerization step of this cascade cyclization. From the cascade cyclization product, (±)-epiglobulol could be synthesized. 相似文献
947.
Rhodium is present at about 0.001 ppm in the earths crust. Rhodium metal is known for its stability in corrosive environments, physical beauty and unique physical and chemical properties. Recent interest in the medical and industrial significance of platinum and to a lesser extent palladium and rhodium has been accompanied by an increasing interest in their determination at low levels.Platinum group elements (PGEs: Pt, Pd, Rh, Ru, Ir and Os) play a decisive role in the performance of catalytic converters, world-wide applied in vehicles and in some household utensils, to reduce the emission of gaseous pollutants, such as carbon monoxide, nitrogen oxides and hydrocarbons. Since then, approximately 73% of the world production of rhodium is consumed in the production of autocatalyst. However, the hot exhaust gases flowing through the converter cause abrasion of these units, leading to the emission of these elements to the environment. The concentration level of rhodium (also platinum and palladium) is still very low in the nature; accordingly, their determination in environmental samples specially appears to be a challenging task for analytical chemists. In recent years, the development of analytical methods for the determination of rhodium has increased.The aim of the present review is to evaluate the utility of atomic absorption spectrometry, applied for the quantification of rhodium in different materials, such as environmental, biological, metallurgical and geological samples. 相似文献
948.
Eugenio Simón-Manso 《Journal of organometallic chemistry》2006,691(3):380-386
The chiral ligand S-(Ph2P)2N(CHMePh) reacts with Ni(CO)4 in benzene solution to yield the mononuclear complex [Ni(CO)2{κ2-(PPh2)2N(CHMePh)}] (1). The reactions of the chiral ligand with the solvated complexes [(η5-C5Me5)MCl(solvent)2]BF4 (M = Rh, Ir) or with the binuclear complex [{(η6-C6Me6)RuCl}2(μ-Cl)] in the presence of a chloride scavenger, give cationic complexes of the type [(ηn-ring)MCl{κ2-(PPh2)2N(CHMePh)}]BF4 [ηn-ring = η5-C5Me5; M = Rh (2), Ir (3). η6-C6Me6; M = Ru (4)]. The 31P NMR spectra of compounds 2-4 show two signals corresponding of two phosphorus nuclei with different chemical environments. The related complex [(η5-C5H5)Fe(CO){κ2-(PPh2)2N(CHMePh)}]BF4 (5) was prepared by reaction of the ligand with the complex [(η5-C5H5)Fe(CO)2I] in toluene following by a metathesis with AgBF4. This compound exhibits only one signal in the 31P NMR spectra at room temperature, which splits into two signals at low temperature (213 K). The crystal structures of complexes 2, 3 and 5 have been determined by X-ray diffraction studies. All complexes show the presence of an intramolecular π-stacking interaction. The separation between least-squares planes defined by the two intramolecularly stacked phenyl rings are in the range 3.318-3.649 Å. 相似文献
949.
Xueyun Zhang Zisong Qi Xingwei Li 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2014,126(40):10970-10974
[Cp*RhIII]‐catalyzed C H activation of arenes assisted by an oxidizing N O or N N directing group has allowed the construction of a number of hetercycles. In contrast, a polar N O bond is well‐known to undergo O‐atom transfer (OAT) to alkynes. Despite the liability of N O bonds in both C H activation and OAT, these two important areas evolved separately. In this report, [Cp*RhIII] catalysts integrate both areas in an efficient redox‐neutral coupling of quinoline N‐oxides with alkynes to afford α‐(8‐quinolyl)acetophenones. In this process the N O bond acts as both a directing group for C H activation and as an O‐atom donor. 相似文献
950.