Search results

Search for "iridium" in Full Text gives 124 result(s) in Beilstein Journal of Organic Chemistry.

Eosin Y-catalyzed visible-light-mediated aerobic oxidative cyclization of N,N-dimethylanilines with maleimides

  • Zhongwei Liang,
  • Song Xu,
  • Wenyan Tian and
  • Ronghua Zhang

Beilstein J. Org. Chem. 2015, 11, 425–430, doi:10.3762/bjoc.11.48

Graphical Abstract
  • light, which is clean, abundant, and renewable. The pioneering work in this research area, reported by the groups of MacMillan [7][8][9], Yoon [10][11], Stephenson [12][13] and others [14][15][16][17][18], has demonstrated that ruthenium and iridium complexes as visible light photoredox catalysts are
  • capable of catalyzing a broad range of useful reactions. A variety of new methods have been developed to accomplish known and new chemical transformations by means of these transition metal-based photocatalysts so far. However, the ruthenium and iridium catalysts usually are high-cost, potentially toxic
PDF
Album
Supp Info
Full Research Paper
Published 01 Apr 2015

Cross-dehydrogenative coupling for the intermolecular C–O bond formation

  • Igor B. Krylov,
  • Vera A. Vil’ and
  • Alexander O. Terent’ev

Beilstein J. Org. Chem. 2015, 11, 92–146, doi:10.3762/bjoc.11.13

Graphical Abstract
  • halides were used as oxidants. Ruthenium, iridium, and palladium complexes acted as catalysts. In most cases, structurally simple alcohols, which are taken in a large excess relative to the CH-reagent, served as OH-reagents. The exception is a study [95], in which the coupling was accomplished using an
PDF
Album
Review
Published 20 Jan 2015

An integrated photocatalytic/enzymatic system for the reduction of CO2 to methanol in bioglycerol–water

  • Michele Aresta,
  • Angela Dibenedetto,
  • Tomasz Baran,
  • Antonella Angelini,
  • Przemysław Łabuz and
  • Wojciech Macyk

Beilstein J. Org. Chem. 2014, 10, 2556–2565, doi:10.3762/bjoc.10.267

Graphical Abstract
  • ] [Cp*Rh(bpy)(H2O)]Cl2 [aquo(2,2’-bipyridine)(pentamethylcyclopentadienyl)]rhodium(III), where Cp* = pentamethylcyclopentadienyl. For comparison we have also used its iridium analog, with phenantroline as a bidentate N-ligand replacing bpy. Iridium showed interesting activity, comparable to that of Rh
PDF
Album
Full Research Paper
Published 03 Nov 2014

Visible light photoredox-catalyzed deoxygenation of alcohols

  • Daniel Rackl,
  • Viktor Kais,
  • Peter Kreitmeier and
  • Oliver Reiser

Beilstein J. Org. Chem. 2014, 10, 2157–2165, doi:10.3762/bjoc.10.223

Graphical Abstract
  • reduction potential (E0 = −1.51 V vs E0 = −1.31 V) [11]. Having identified a promising activation group for deoxygenation in combination with an iridium-based photocatalyst, different solvents and reaction temperatures were examined for the conversion of 3 (Table 2). Gratifyingly, toxic DMF could be
  • iridium-catalyzed hydrogenation mechanism as an alternative for a photochemical pathway of the reaction could be ruled out; in the presence of 5 atm H2 without irradiation under otherwise unchanged reaction conditions no deoxygenation of the benzoates could be observed even after prolonged reaction times
  • desirable to install the activating benzoate group in situ rather than in a foregoing reaction step. Also, considering its high price the employment of only small amounts of iridium-based catalyst and lower priced triethylamine instead of costly diisopropylethylamine would be desirable. Taking 14 as model
PDF
Album
Supp Info
Video
Full Research Paper
Published 10 Sep 2014

Visible-light-induced, Ir-catalyzed reactions of N-methyl-N-((trimethylsilyl)methyl)aniline with cyclic α,β-unsaturated carbonyl compounds

  • Dominik Lenhart and
  • Thorsten Bach

Beilstein J. Org. Chem. 2014, 10, 890–896, doi:10.3762/bjoc.10.86

Graphical Abstract
  • -induced, iridium-catalyzed addition reactions to cyclic α,β-unsaturated carbonyl compounds. Typical reaction conditions included the use of one equivalent of the reaction substrate, 1.5 equivalents of the aniline and 2.5 mol % (in MeOH) or 1.0 mol % (in CH2Cl2) [Ir(ppy)2(dtbbpy)]BF4 as the catalyst. Two
  • lactone and lactam substrates, the latter products were the only products isolated. For the six-membered lactones and lactams and for cyclopentenone the simple addition products prevailed. Keywords: cyclization; electron transfer; iridium; photochemistry; photoredox catalysis; radical reactions
  • as a co-solvent [39] and that the diastereoselectivity depends both on the stereogenic center at C5 and on the chirality of the menthyl (Men) backbone [40]. In more recent work [41][42], Nishibayashi et al. showed that iridium complexes can serve as efficient PET catalysts for the addition of α
PDF
Album
Supp Info
Full Research Paper
Published 17 Apr 2014

Metal and metal-free photocatalysts: mechanistic approach and application as photoinitiators of photopolymerization

  • Jacques Lalevée,
  • Sofia Telitel,
  • Pu Xiao,
  • Marc Lepeltier,
  • Frédéric Dumur,
  • Fabrice Morlet-Savary,
  • Didier Gigmes and
  • Jean-Pierre Fouassier

Beilstein J. Org. Chem. 2014, 10, 863–876, doi:10.3762/bjoc.10.83

Graphical Abstract
  • well as the typical oxidation and reduction agents used in both reductive or oxidative cycles are gathered. The chemical mechanisms associated with various systems are also given. As compared to classical iridium-based photocatalysts which are mainly active upon blue light irradiation, a new
  • photocatalyst Ir(piq)2(tmd) (also known as bis(1-phenylisoquinolinato-N,C2’)iridium(2,2,6,6-tetramethyl-3,5-heptanedionate) is also proposed as an example of green light photocatalyst (toward the long wavelength irradiation). The chemical mechanisms associated with Ir(piq)2(tmd) are investigated by ESR spin
  • of sustainable radical-mediated chemical processes under very soft irradiation conditions (e.g., household fluorescence or LED bulbs, halogen lamps, sunlight, Xe lamp), e.g., enantioselective alkylation, cycloaddition, etc. [1][2][3][4][5][6][7][8][9][10][11][12][13][14]. Ruthenium- and iridium-based
PDF
Album
Full Research Paper
Published 15 Apr 2014

Silica: An efficient catalyst for one-pot regioselective synthesis of dithioethers

  • Samir Kundu,
  • Babli Roy and
  • Basudeb Basu

Beilstein J. Org. Chem. 2014, 10, 26–33, doi:10.3762/bjoc.10.5

Graphical Abstract
  • and also as spacers in metal-organic frameworks [9][10][11][12][13][14]. For example, vicinal dithioether-based zirconium and titanium complexes have been used for alkene polymerization and hydroamination [15][16][17][18]. Chiral dithioethers have been prepared and their iridium complexes have been
PDF
Album
Supp Info
Full Research Paper
Published 07 Jan 2014

Recent advances in transition metal-catalyzed Csp2-monofluoro-, difluoro-, perfluoromethylation and trifluoromethylthiolation

  • Grégory Landelle,
  • Armen Panossian,
  • Sergiy Pazenok,
  • Jean-Pierre Vors and
  • Frédéric R. Leroux

Beilstein J. Org. Chem. 2013, 9, 2476–2536, doi:10.3762/bjoc.9.287

Graphical Abstract
  • proceed through the direct introduction of CnF2n+1+, CnF2n+1• or CnF2n+1−, but of a perfluoralkylmethylene (Scheme 10). 3.3.2 Ir-catalyzed perfluoroalkylation of Csp2–H bonds. As a preamble, it should be noted that D. W. C. MacMillan and E. J. Cho tested iridium complexes along with the ruthenium
  • analogues in the photoredox catalytic reactions discussed in section 3.3.1. Although also active, the iridium catalysts showed lower selectivity and are more expensive [105][106][107]. A different strategy was simultaneously reported by the groups of J. F. Hartwig and Q. Shen [35][37]. The approach consists
PDF
Album
Review
Published 15 Nov 2013

Silica sulfuric acid: a reusable solid catalyst for one pot synthesis of densely substituted pyrrole-fused isocoumarins under solvent-free conditions

  • Sudipta Pathak,
  • Kamalesh Debnath and
  • Animesh Pramanik

Beilstein J. Org. Chem. 2013, 9, 2344–2353, doi:10.3762/bjoc.9.269

Graphical Abstract
  • attention of synthetic as well as medicinal chemists [7][8][9]. Various methodologies for the synthesis of isocoumarins have been reported such as the reaction of o-halobenzoic acids and 1,3-diketones through a copper-catalyzed tandem sequential cyclization/addition/deacylation process [10][11], an iridium
PDF
Album
Supp Info
Full Research Paper
Published 04 Nov 2013

Studies on the photodegradation of red, green and blue phosphorescent OLED emitters

  • Susanna Schmidbauer,
  • Andreas Hohenleutner and
  • Burkhard König

Beilstein J. Org. Chem. 2013, 9, 2088–2096, doi:10.3762/bjoc.9.245

Graphical Abstract
  • Susanna Schmidbauer Andreas Hohenleutner Burkhard Konig Institut für Organische Chemie, Universität Regensburg, Universitätsstraße 31, D-93053 Regensburg, Germany 10.3762/bjoc.9.245 Abstract The photodegradation behavior of four well-established iridium emitters was investigated. Irradiation of
  • solvents are discussed for the different investigated iridium complexes. Some of the resulting degradation products could be identified by using LC–MS or other analytical techniques. The results show how even small structural changes can have a huge influence on rate and mechanism of the photodegradation
  • . The observations from this study may help to better understand degradation processes occurring during the handling of the materials, but also during device processing and operation. Keywords: iridium complexes; OLED; photoinduced degradation; phosphorescent emitters; Introduction For applications
PDF
Album
Supp Info
Full Research Paper
Published 11 Oct 2013

The chemistry of amine radical cations produced by visible light photoredox catalysis

  • Jie Hu,
  • Jiang Wang,
  • Theresa H. Nguyen and
  • Nan Zheng

Beilstein J. Org. Chem. 2013, 9, 1977–2001, doi:10.3762/bjoc.9.234

Graphical Abstract
  • ). Therefore, a photocatalyst is often required to initialize electron-transfer reactions with amines. Some of the frequently used photocatalysts include ruthenium [24][25][26] and iridium [27][28] polypyridyl complexes as well as organic dyes [29][30] that are absorbed in the visible-light region. They all
PDF
Album
Review
Published 01 Oct 2013

Aqueous reductive amination using a dendritic metal catalyst in a dialysis bag

  • Jorgen S. Willemsen,
  • Jan C. M. van Hest and
  • Floris P. J. T. Rutjes

Beilstein J. Org. Chem. 2013, 9, 960–965, doi:10.3762/bjoc.9.110

Graphical Abstract
  • Jorgen S. Willemsen Jan C. M. van Hest Floris P. J. T. Rutjes Radboud University Nijmegen, Institute for Molecules and Materials, Heyendaalseweg 135, 6525 AJ Nijmegen, The Netherlands 10.3762/bjoc.9.110 Abstract Water-soluble dendritic iridium catalysts were synthesized by attaching a reactive
  • examples, we decided to design a metallodendrimer that would show catalytic activity in a cascade process while compartmentalized under aqueous conditions. To this end, an iridium catalyst was selected that was known to be suitable for reductive amination in an aqueous environment. We showed that by
  • catalyst can also be easily removed from the reaction mixture after the reaction has been completed (Figure 1). Results and Discussion To study this approach, we selected iridium catalyst 3, which has been previously successfully applied in aqueous reductive aminations [27]. The catalyst is based on
PDF
Album
Supp Info
Full Research Paper
Published 17 May 2013

Tandem aldehyde–alkyne–amine coupling/cycloisomerization: A new synthesis of coumarins

  • Maddi Sridhar Reddy,
  • Nuligonda Thirupathi and
  • Madala Haribabu

Beilstein J. Org. Chem. 2013, 9, 180–184, doi:10.3762/bjoc.9.21

Graphical Abstract
  • , cobalt, iridium and iron. Similarly, cycloisomerization of alkynols and alkynamines has also been an attractive approach for the synthesis of various known and new heterocyclic frameworks [2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20][21][22]. Various alkynophilic catalysts such as
PDF
Album
Supp Info
Full Research Paper
Published 28 Jan 2013

Flow photochemistry: Old light through new windows

  • Jonathan P. Knowles,
  • Luke D. Elliott and
  • Kevin I. Booker-Milburn

Beilstein J. Org. Chem. 2012, 8, 2025–2052, doi:10.3762/bjoc.8.229

Graphical Abstract
  • also be performed with visible-light photocatalysis, in this case with either ruthenium or iridium catalysts (Scheme 14). Again, residence times in the 100 µL microreactor were significantly shorter than those for the batch reactor, and in this case the microflow system also allowed reactions that were
PDF
Album
Review
Published 21 Nov 2012

Rh(III)-catalyzed directed C–H bond amidation of ferrocenes with isocyanates

  • Satoshi Takebayashi,
  • Tsubasa Shizuno,
  • Takashi Otani and
  • Takanori Shibata

Beilstein J. Org. Chem. 2012, 8, 1844–1848, doi:10.3762/bjoc.8.212

Graphical Abstract
  • structures. For instance, a 1,2-disubstituted ferrocenyl ligand, Xyliphos ((R)-1-[(S)-2-(diphenylphosphanyl)ferrocenyl]ethyl bis(3,5-dimethylphenyl)phosphane) is used for iridium-catalyzed enantioselective hydrogenation to produce the herbicide (S)-metolachlor on a scale of more than 10000 tons/year [5
PDF
Album
Supp Info
Letter
Published 29 Oct 2012

Iridium-catalyzed intramolecular [4 + 2] cycloadditions of alkynyl halides

  • Andrew Tigchelaar and
  • William Tam

Beilstein J. Org. Chem. 2012, 8, 1765–1770, doi:10.3762/bjoc.8.201

Graphical Abstract
  • Andrew Tigchelaar William Tam Guelph-Waterloo Centre for Graduate Work in Chemistry and Biochemistry, Department of Chemistry, University of Guelph, Guelph, Ontario, Canada N1G 2W1 10.3762/bjoc.8.201 Abstract Iridium-catalyzed intramolecular [4 + 2] cycloadditions of diene-tethered alkynyl
  • halides were investigated by using [IrCl(cod)]2 as catalyst, and dppe was found to be the most suitable phosphine ligand for the reaction. No oxidative insertion of the iridium into the carbon–halide bond was observed, and the reactions proceeded to provide the halogenated cycloadducts in good yield (75
  • –94%). These results are the first examples of cycloadditions of alkynyl halides using an iridium catalyst. Keywords: alkynyl halide; cycloaddition; diene-tethered alkyne; iridium; transition-metal catalyst; Introduction Iridium complexes have been used as catalysts for a wide variety of reactions
PDF
Album
Supp Info
Full Research Paper
Published 16 Oct 2012

Metal–ligand multiple bonds as frustrated Lewis pairs for C–H functionalization

  • Matthew T. Whited

Beilstein J. Org. Chem. 2012, 8, 1554–1563, doi:10.3762/bjoc.8.177

Graphical Abstract
  • require cooperative activation of substrates. One well-defined case with iridium(I) carbenes generated by multiple C−H activations is explored as a proof of principle. Note that the purpose of this review is not to provide an exhaustive list of examples of reactivity consistent with the description of
  • character of Fe. In contrast to the silylene and borylene examples presented above, square-planar carbene complexes of iridium(I) often react in a fashion that is dictated by the nucleophilic metal center. An early example of this type of complex was an amidophosphine-supported iridium methylene reported by
  • release ethylene and make an iridium(I) trimethylphosphine complex (Scheme 10). More recently, Werner reported several square-planar iridium(I) carbene complexes that react with acid to selectively protonate the iridium center (i.e., the more basic/nucleophilic site) [66][67]. Whited and Grubbs explored
PDF
Album
Supp Info
Review
Published 18 Sep 2012

Stereoselective synthesis of trans-fused iridoid lactones and their identification in the parasitoid wasp Alloxysta victrix, Part I: Dihydronepetalactones

  • Nicole Zimmermann,
  • Robert Hilgraf,
  • Lutz Lehmann,
  • Daniel Ibarra and
  • Wittko Francke

Beilstein J. Org. Chem. 2012, 8, 1246–1255, doi:10.3762/bjoc.8.140

Graphical Abstract
  • chain at C5 through chelation. We chose Crabtree’s iridium catalyst ([Ir(cod)PCy3(py)]PF6) which has been reported to furnish excellent facial selectivities during directed hydrogenations of cyclic olefins [32][33][34]. Hydrogenation of acetate 16 in the presence of 11 mol % of Crabtree’s catalyst under
PDF
Album
Supp Info
Full Research Paper
Published 07 Aug 2012

Synthesis of highly functionalized β-aminocyclopentanecarboxylate stereoisomers by reductive ring opening reaction of isoxazolines

  • Melinda Nonn,
  • Loránd Kiss,
  • Reijo Sillanpää and
  • Ferenc Fülöp

Beilstein J. Org. Chem. 2012, 8, 100–106, doi:10.3762/bjoc.8.10

Graphical Abstract
  •  3). Combinations of NaBH4 (as a mild and selective reducing agent) with cobalt, nickel, iridium or rhodium halide have previously been employed for cleavage of the isoxazoline ring system, which is otherwise inert to NaBH4 without such metal halide additives [50]. Accordingly, we investigated the
PDF
Album
Full Research Paper
Published 17 Jan 2012

Asymmetric Au-catalyzed cycloisomerization of 1,6-enynes: An entry to bicyclo[4.1.0]heptene

  • Alexandre Pradal,
  • Chung-Meng Chao,
  • Patrick Y. Toullec and
  • Véronique Michelet

Beilstein J. Org. Chem. 2011, 7, 1021–1029, doi:10.3762/bjoc.7.116

Graphical Abstract
  • chiral iridium catalyst [41] (Scheme 1, reaction 2). We and others recently pursued the improvement and development of this enantioselective process, by employing platinum [42][43][44], rhodium [45] or gold [46][47][48] complexes. Following our previous work with chiral gold catalysts [46], we report a
  • % isolated yield respectively) resulting from 5-exo- and 6-endo cycloisomerization reactions [20][66]. Thus, the gold catalytic system cannot compete with the results obtained for the cyclizations of nitrogen-tethered enynes in the presence of iridium, platinum or rhodium catalysts [41][42][43][44][45]. The
PDF
Album
Supp Info
Full Research Paper
Published 26 Jul 2011

Advances in synthetic approach to and antifungal activity of triazoles

  • Kumari Shalini,
  • Nitin Kumar,
  • Sushma Drabu and
  • Pramod Kumar Sharma

Beilstein J. Org. Chem. 2011, 7, 668–677, doi:10.3762/bjoc.7.79

Graphical Abstract
  • composition and structure of the inhibitor [70]. Novel heteroleptic iridium complexes containing the 1-substituted-4-phenyl-1H-1,2,3-triazole cyclometalating ligand were synthesized by the [3 + 2] Huisgen dipolar cycloaddition method which was utilized to prepare a class of bidentate ligands by adding
  • different substituents to the triazole nucleus. By a judicious choice of ligands, a library of new luminescent ionic iridium complexes was prepared [71]. 3-Amino-1,2,4-triazole is an inhibitor of mitochondrial and chloroplast function. Commercial grade 3-amino-1,2,4-triazole is used as a herbicide and
PDF
Album
Review
Published 25 May 2011

Functional properties of metallomesogens modulated by molecular and supramolecular exotic arrangements

  • Alessandra Crispini,
  • Mauro Ghedini and
  • Daniela Pucci

Beilstein J. Org. Chem. 2009, 5, No. 54, doi:10.3762/bjoc.5.54

Graphical Abstract
  • ligand extensively used in the synthesis of cyclometallated iridium(III) and platinum(II) derivatives [46][47] but whose reactivity towards Pd(II) centres is unexplored. This kind of ligand has been functionalised with a chiral group such as a cholesteryl ester unit, introduced as terminal substituent in
PDF
Album
Review
Published 12 Oct 2009

Iridium-catalyzed asymmetric ring-opening reactions of oxabicyclic alkenes with secondary amine nucleophiles

  • Dingqiao Yang,
  • Ping Hu,
  • Yuhua Long,
  • Yujuan Wu,
  • Heping Zeng,
  • Hui Wang and
  • Xiongjun Zuo

Beilstein J. Org. Chem. 2009, 5, No. 53, doi:10.3762/bjoc.5.53

Graphical Abstract
  • Dingqiao Yang Ping Hu Yuhua Long Yujuan Wu Heping Zeng Hui Wang Xiongjun Zuo School of Chemistry and Environment, South China Normal University, Guangzhou 510006, People’s Republic of China, Fax: (+86)-20-39310187; Phone: (+86)-20-85210087 10.3762/bjoc.5.53 Abstract Iridium-catalyzed asymmetric
  • and 5 mol % bisphosphine ligand (S)-p-Tol-BINAP. The trans-configuration of 3f was confirmed by X-ray crystallography. Keywords: chiral bisphosphine ligand; iridium catalyst; oxabicyclic alkenes; ring-opening reaction; Introduction Substituted dihydronaphthalenes are important molecules with
  • metal catalysts may be used for asymmetric ring-opening reactions of oxabicyclic alkenes. These include complexes of copper [20][21][22][23][24][25], palladium [14][15][26][27][28][29][30][31], iron [32], and nickel [33][34][35][36]. Recently, we reported for the first time iridium-catalyzed asymmetric
PDF
Album
Supp Info
Full Research Paper
Published 09 Oct 2009

Sordarin, an antifungal agent with a unique mode of action

  • Huan Liang

Beilstein J. Org. Chem. 2008, 4, No. 31, doi:10.3762/bjoc.4.31

Graphical Abstract
  • -unsaturated ester, which was subjected to Pearlman hydrogenolysis of the benzyl group and selective catalytic reduction of the non-conjugated olefin with iridium black. The latter step proceeded in a predominately syn manner to afford intermediate 12, which was oxidized to cyclopentadiene 13 through TBS
PDF
Album
Review
Published 05 Sep 2008
Other Beilstein-Institut Open Science Activities