CF₃SO₂X (X = Na, Cl) as reagents for trifluoromethylation, trifluoromethylsulfenyl-, -sulfinyl- and -sulfonylation and chlorination. Part 2: Use of CF₃SO₂Cl

• Hélène Chachignon,
• Hélène Guyon and
• Dominique Cahard

Beilstein J. Org. Chem. 2017, 13, 2800–2818, doi:10.3762/bjoc.13.273

• ]iridium(III) hexafluorophosphate, Ir(ppy)2(dtbbpy)PF6, various aryl enol acetates carrying electron-donating or electron-withdrawing groups were converted into the corresponding products in high yields. Moreover, the reaction was compatible with cyclic and acyclic branched enol acetates. Quite

• interestingly, when the reaction was performed using an aryl or alkylsulfonyl chloride, instead of trifluoromethanesulfonyl chloride, no extrusion of the SO2 moiety was observed, and the sulfonated products were recovered. The reaction mechanism involved excitation of the iridium catalyst under visible light to

CF₃SO₂X (X = Na, Cl) as reagents for trifluoromethylation, trifluoromethylsulfenyl-, -sulfinyl- and -sulfonylation. Part 1: Use of CF₃SO₂Na

• Hélène Guyon,
• Hélène Chachignon and
• Dominique Cahard

Beilstein J. Org. Chem. 2017, 13, 2764–2799, doi:10.3762/bjoc.13.272

• authors also realised the same chemical transformation under visible light irradiation at 450 nm by means of the iridium photocatalyst Ir[dF(CF3)ppy]2(dtbbpy)PF6 ([4,4’-bis(tert-butyl)-2,2’-bipyridine]bis[3,5-difluoro-2-[5-(trifluoromethyl)-2-pyridinyl]phenyl]iridium(III) hexafluorophosphate), which

• presence of an iridium photoredox catalyst as reported by Zhu, Zhang and co-workers [41]. Of the photocatalysts tested, Ir[dF(CF3)ppy]2(dtbbpy)PF6 had appropriate redox potentials and gave the best results. A wide range of terminal alkenes featuring several functional groups reacted with exclusive anti

Mechanochemical synthesis of small organic molecules

• Tapas Kumar Achar,
• Anima Bose and
• Prasenjit Mal

Beilstein J. Org. Chem. 2017, 13, 1907–1931, doi:10.3762/bjoc.13.186

• the metal catalyst from rhodium to iridium. In 2016, using an Ir(III) catalyst an unprecedented ortho-selective Csp2–H bond amidation of benzamides with sulfonyl azides as the amide source was done under solvent-free ball mill conditions (Scheme 51) [183]. They could also isolate cyclic iridium

Oxidative dehydrogenation of C–C and C–N bonds: A convenient approach to access diverse (dihydro)heteroaromatic compounds

• Santanu Hati,
• Ulrike Holzgrabe and
• Subhabrata Sen

Beilstein J. Org. Chem. 2017, 13, 1670–1692, doi:10.3762/bjoc.13.162

• the ring containing the nitrogen atom. The dehydrogenation strategy is an atom economical, efficient and sustainable method to access nitrogen containing heteroaromatic molecules. They can be either achieved by metals (like iridium, ruthenium, aluminum etc.) mediated processes (in absence of hydrogen

• acceptor) or via oxidative dehydrogenation in the presence of appropriate oxidants. In absence of hydrogen acceptors, post dehydrogenation the hydrogen is released as H2↑. Catalysts such as iridium pincer complexes, CuAl2O3, hydroxyapatite bound palladium and ruthenium hydride complexes have been harnessed

• combination of heterogeneous polymer-supported bi-metallic platinum/iridium alloyed nanoclusters and 5,5’,6,6’-tetrahydroxy-3,3,3’,3’-tetramethyl-1,1’-spiro-bisindane (TTSBI) facilitated a one-pot condensation and oxidative dehydrogenation of o-aminobenzylamine to generate quinazoline derivatives 79 under

Chemoselective synthesis of diaryl disulfides via a visible light-mediated coupling of arenediazonium tetrafluoroborates and CS₂

• Jing Leng,
• Shi-Meng Wang and
• Hua-Li Qin

Beilstein J. Org. Chem. 2017, 13, 903–909, doi:10.3762/bjoc.13.91

• . Ru(bpy)3Cl2 catalyzed this coupling to afford the desired product 3a in a moderate yield of 65% (Table 3, entry 8). However, when the iridium-based photocatalysts Ir(ppy)3 [24], [Ir(ppy)2(bpy)]PF6 and [Ir(ppy)2(dtbbpy)]PF6 (bpy = 2,2’-bipyridine, ppy = 2-phenylpyridine, dtbbpy = 4,4’-di-tert-butyl

Ultrasound-promoted organocatalytic enamine–azide [3 + 2] cycloaddition reactions for the synthesis of ((arylselanyl)phenyl-1H-1,2,3-triazol-4-yl)ketones

• Gabriel P. Costa,
• Natália Seus,
• Juliano A. Roehrs,
• Raquel G. Jacob,
• Ricardo F. Schumacher,
• Thiago Barcellos,
• Rafael Luque and
• Diego Alves

Beilstein J. Org. Chem. 2017, 13, 694–702, doi:10.3762/bjoc.13.68

• most attractive way for their preparation is the thermal 1,3-dipolar cycloaddition of alkynes and azides, introduced by Huisgen which usually gives rise to a mixture of 1,4 and 1,5-isomers [16][17][18][19]. More recently, transition metal catalysts based on copper, ruthenium, silver and iridium salts

Effect of the ortho-hydroxy group of salicylaldehyde in the A³ coupling reaction: A metal-catalyst-free synthesis of propargylamine

• Sujit Ghosh,
• Kinkar Biswas,
• Suchandra Bhattacharya,
• Pranab Ghosh and
• Basudeb Basu

Beilstein J. Org. Chem. 2017, 13, 552–557, doi:10.3762/bjoc.13.53

• ], mercury [26], cobalt [27], iridium [28], ruthenium [29], indium [30] etc. Other methods towards the synthesis of propargylamine include: alkynylation of imine [31][32][33], enamine [34], and Csp³–H bonds adjacent to N-atoms [35][36]. In the A3 coupling, the role of the metal catalyst is believed to

Synthesis of 1-indanones with a broad range of biological activity

• Marika Turek,
• Dorota Szczęsna,
• Marek Koprowski and
• Piotr Bałczewski

Beilstein J. Org. Chem. 2017, 13, 451–494, doi:10.3762/bjoc.13.48

• substituents. In the previous studies of the reductive Nazarov cyclization, similar results were obtained – two E and Z dienone isomers were converted into one diastereoisomeric product [70][71]. A dicationic iridium(III)-catalyzed Nazarov cyclization has been applied for the synthesis of functionalized 1

• carried out in the presence of an iridium catalyst and antimony hexafluoride (AgSbF6) under mild conditions. The starting chalcones were almost completely converted into 1-indanones 138–142 and isolated in very good yields. Our research group synthesized 3-aryl-1-indanones 148 and previously unknown 3

NMR reaction monitoring in flow synthesis

• M. Victoria Gomez and
• Antonio de la Hoz

Beilstein J. Org. Chem. 2017, 13, 285–300, doi:10.3762/bjoc.13.31

• concentrations of 1 mmol L−1 in single-scan experiments. As a proof-of-concept, they studied the transfer hydrogenation process of acetophenone with isopropanol catalysed by iridium complexes. The reaction was performed in batch and the sample was introduced into the magnet with a pump and Teflon tubing to form

Copper-catalyzed asymmetric sp³ C–H arylation of tetrahydroisoquinoline mediated by a visible light photoredox catalyst

• Pierre Querard,
• Inna Perepichka,
• Eli Zysman-Colman and
• Chao-Jun Li

Beilstein J. Org. Chem. 2016, 12, 2636–2643, doi:10.3762/bjoc.12.260

• photoredox system might help, which indeed has improved the reaction yield and enantioselectivity. Different iridium and ruthenium photoredox catalysts were evaluated and [Ir(ppy)2(dtbbpy)]PF6 was found to be the most efficient [32]. With this iridium photoredox catalyst, TBHP, and copper(I) bromide co

• (SET), reducing the iridium complex to Ir(II) III and oxidizing the the nitrogen of THIQ IV to its radical cation V, which then undergoes a hydride abstraction to form the iminium salt form VI, of the THIQ. The pre-formed chiral PhCu–PyBox complex [38], coordinates to the iminium cation VI, followed by

High performance p-type molecular electron donors for OPV applications via alkylthiophene catenation chromophore extension

• Paul B. Geraghty,
• Calvin Lee,
• Jegadesan Subbiah,
• Wallace W. H. Wong,
• James L. Banal,
• Mohammed A. Jameel,
• Trevor A. Smith and
• David J. Jones

Beilstein J. Org. Chem. 2016, 12, 2298–2314, doi:10.3762/bjoc.12.223

• large scale use of tin reagents we required the key bis-borylated benzodithiophene (BDT) core 13, which was synthesised from the known BDT core 12 using iridium catalyzed borylation via CH-activation. The bis-borylated product was isolated by precipitation on addition of isopropanol (IPA), and an

Palladium-catalyzed ring-opening reactions of cyclopropanated 7-oxabenzonorbornadiene with alcohols

• Katrina Tait,
• Oday Alrifai,
• Rebecca Boutin,
• Jamie Haner and
• William Tam

Beilstein J. Org. Chem. 2016, 12, 2189–2196, doi:10.3762/bjoc.12.209

• the use of platinum catalysts [19] or palladium catalysts with zinc co-catalyst with phenol nucleophiles [20]. Meanwhile, anti-stereoisomeric products 5 and 6 are obtained when copper catalysts are used with alkyl nucleophiles [21], if rhodium [22] or iridium catalysts are used in the presence of

Experimental and theoretical investigations on the high-electron donor character of pyrido-annelated N-heterocyclic carbenes

• Michael Nonnenmacher,
• Dominik M. Buck and
• Doris Kunz

Beilstein J. Org. Chem. 2016, 12, 1884–1896, doi:10.3762/bjoc.12.178

• containing the tert-butyl substituted dipyridocarbene ligand dipiytBu. For iridium complexes [Ir(CO)2Cl(NHC)] (NHC = imidazolidin-2-ylidene) a preferred cis-CO exchange was reported and an activation energy of 12.7–12.9 kcal/mol was determined by NMR spectroscopy for this process [60]. However, an exchange

Cp₂TiCl/D₂O/Mn, a formidable reagent for the deuteration of organic compounds

• Antonio Rosales and
• Ignacio Rodríguez-García

Beilstein J. Org. Chem. 2016, 12, 1585–1589, doi:10.3762/bjoc.12.154

• C–H bonds [8][9]. More recently, organometallic catalysts have been used in the development of methods for deuteration of organic compounds. In this sense, it has been reported that iridium complexes can catalyse the H/D exchange of arenes, cyclic alkenes and vinyl groups [10][11][12]. Ruthenium

NeoPHOX – a structurally tunable ligand system for asymmetric catalysis

• Jaroslav Padevět,
• Marcus G. Schrems,
• Robin Scheil and
• Andreas Pfaltz

Beilstein J. Org. Chem. 2016, 12, 1185–1195, doi:10.3762/bjoc.12.114

• ligands were tested in the iridium-catalyzed asymmetric hydrogenation and palladium-catalyzed allylic substitution. In both reactions high enantioselectivities were achieved, that were comparable to the enantioselectivities obtained with the up to now best NeoPHOX ligand derived from expensive tert

• -leucine. Keywords: allylic substitution; asymmetric hydrogenation; iridium; N,P ligand; palladium; Introduction Since their introduction and first successful application in enantioselective palladium-catalyzed allylic substitution in 1993 [1][2][3], chiral phosphinooxazolines (PHOX ligands) have emerged

• as a widely used privileged ligand class [4][5][6][7][8][9][10][11][12]. One of the major areas of application of PHOX and related N,P ligands is the iridium-catalyzed asymmetric hydrogenation [13][14][15][16]. Compared to rhodium and ruthenium catalysts, iridium complexes derived from chiral N,P

Catalytic asymmetric synthesis of biologically important 3-hydroxyoxindoles: an update

• Bin Yu,
• Hui Xing,
• De-Quan Yu and
• Hong-Min Liu

Beilstein J. Org. Chem. 2016, 12, 1000–1039, doi:10.3762/bjoc.12.98

• Recently, iridium has emerged as a powerful catalyst for C–H bond functionalization [20][21][22][23]. In 2014, Yamamoto and co-workers reported a cationic iridium complex catalyzed asymmetric intramolecular hydroarylation of α-ketoamides, yielding 3-substituted 3-hydroxy-2-oxindoles with high

• plausible catalytic cycle was proposed as shown in Scheme 8: [Ir(cod)2](BArF4) and the ligand L4 formed the [Ir] precatalyst in situ, which then activated a C–H bond of the substrate to generate aryl–iridium complex A. Subsequent intramolecular asymmetric hydroarylation of intermediate B produced iridium

• alkoxide species C. Reductive elimination of species C gave the product and regenerated the active iridium catalyst. Recently, Qiu and co-workers developed a novel chiral ligand L5 based on a chiral-bridged biphenyl backbone and successfully achieved the asymmetric addition of arylboronic acids to N

1H-Imidazol-4(5H)-ones and thiazol-4(5H)-ones as emerging pronucleophiles in asymmetric catalysis

• Antonia Mielgo and
• Claudio Palomo

Beilstein J. Org. Chem. 2016, 12, 918–936, doi:10.3762/bjoc.12.90

• of thiazol-4(5H)-ones as pronucleophiles in asymmetric catalytic reactions has been investigated in the Michael addition reaction to nitroalkenes and α-silyloxyenones, phosphine-catalyzed γ-addition to allenoates and alkynoates, α-amination reactions and iridium-catalyzed allylic substitution

• bearing the quinoyl moiety provided once again better stereochemical results than 2-naphthylthiazolones. 2.2.3 Iridium-catalyzed allylic substitution reactions. Allylic substitution reactions catalyzed by cyclometalated iridium phosphoramidite complexes constitute a powerful tool for the construction of C

• very narrow range of nucleophiles have been reported to be efficient in this regard (α,α-disubstituted aldehydes [114] and β-ketoesters [115] among others). With the aim of expanding the nucleophile scope of this transformation, in 2014 Hartwig et al. reported a highly diastereoselective iridium

Enantioselective carbenoid insertion into C(sp³)–H bonds

• J. V. Santiago and
• A. H. L. Machado

Beilstein J. Org. Chem. 2016, 12, 882–902, doi:10.3762/bjoc.12.87

• promote the formation of a specific enantiomer. The search for the best balance of these properties of the carbenoid intermediates was also sought through the use of different metals such as copper [3], rhodium [4], iron [5], ruthenium [6], iridium [7], osmium [8], and others. From these, copper and

• , after addition of ligand 1c to the reaction media, the reaction afforded moderate yields, diastereomeric ratio and enantioselectivity. These catalysts were reused over three cycles with progressive yield and enantioselectivity decrease. Iridium-based chiral catalysts Most recently, chiral iridium

• complexes have been used as catalyst for insertion reactions in C(sp3)–H bonds. In 2009, Suematsu and Katsuki published the first study addressed to the use of iridium-based chiral complexes as catalyst for the formation of carbenoid intermediates (Figure 5) [51]. The authors conducted insertion reactions

A modular approach to neutral P,N-ligands: synthesis and coordination chemistry

• Vladislav Vasilenko,
• Torsten Roth,
• Clemens K. Blasius,
• Sebastian N. Intorp,
• Hubert Wadepohl and
• Lutz H. Gade

Beilstein J. Org. Chem. 2016, 12, 846–853, doi:10.3762/bjoc.12.83

• neutral κ2-P,N-ligands comprising an imine and a phosphine binding site. These ligands were reacted with rhodium, iridium and palladium metal precursors and the structures of the resulting complexes were elucidated by means of X-ray crystallography. We observed that subtle changes of the ligand backbone

• donors, with distinct consequences for their coordination chemistry (vide infra). Complex synthesis In the next step of our study we set out to explore the coordination chemistry and structural properties of the synthesized ligands with rhodium(I/III), iridium(I/III) and palladium(II) precursors

• . Reaction of ligands 2 and 3 with (i) preformed [Rh(cod)2]BF4 and (ii) stoichiometric amounts of [Ir(cod)Cl]2 in the presence of AgBF4 gave the corresponding rhodium(I) and iridium(I) complexes [2,3-M(cod)]BF4 in good to excellent yields (Scheme 3). In a similar fashion, analogous complexes of ligands 5 and

Iridium/N-heterocyclic carbene-catalyzed C–H borylation of arenes by diisopropylaminoborane

• Mamoru Tobisu,
• Takuya Igarashi and
• Naoto Chatani

Beilstein J. Org. Chem. 2016, 12, 654–661, doi:10.3762/bjoc.12.65

• C–H borylation of arenes has been widely used in organic synthesis because it allows the introduction of a versatile boron functionality directly onto simple, unfunctionalized arenes. We report herein the use of diisopropylaminoborane as a boron source in C–H borylation of arenes. An iridium(I

• borylation; iridium; N-heterocyclic carbene; Introduction Catalytic C–H borylation of arenes has become an essential tool in organic synthesis [1]. The eminent features of this methodology include 1) no directing group is needed, allowing the direct functionalization of simple arenes; 2) the

• regioselectivity is readily predictable based on steric factors; 3) the resulting boryl group is versatile and can be converted into a variety of carbon- or heteroatom-based substituents. An iridium complex in conjunction with 4,4’-di-tert-butylbipyridine (dtbpy) developed by Ishiyama, Miyaura and Hartwig has

Versatile deprotonated NHC: C,N-bridged dinuclear iridium and rhodium complexes

• Albert Poater

Beilstein J. Org. Chem. 2016, 12, 117–124, doi:10.3762/bjoc.12.13

• , and PMe3 later confirm the H-T coordination as the thermodynamically preferred. It is envisaged the exchange of the metal, from iridium to rhodium, confirming here the innocence of the nature of the metal for such arrangements of the bridging ligands. Keywords: DFT; head-to-head; head-to-tail

• ; iridium; isomerization; N-heterocyclic carbene; rhodium; Introduction In the framework of organometallic chemistry, N-heterocyclic carbenes (NHC) centre a well stablished class of relatively new ligands since in 1991 Arduengo and collaborators isolated the first stable NHC of the imidazole type with

• ], substrate recognition [29] and/or biological systems [30][31]. Among the synthetic methodologies to access to pNHC metal complexes [32][33][34][35][36][37][38][39][40], recently N-arylimine functionalized pNHC iridium complexes were obtained using excess of [Ir(cod)(µ-Cl)]2 [41], and next deprotonation of

Recent advances in metathesis-derived polymers containing transition metals in the side chain

• Ileana Dragutan,
• Valerian Dragutan,
• Bogdan C. Simionescu,
• Albert Demonceau and
• Helmut Fischer

Beilstein J. Org. Chem. 2015, 11, 2747–2762, doi:10.3762/bjoc.11.296

• , followed by functionalization of the latter with n-butylamine to yield 17b, and finally this organic polymer hydroaminated the ethynyl cobalticenium to produce 17 (Scheme 7B). Both protocols embody an elegant and original ROMP-based access to cobalticenium-containing polyelectrolytes. Ruthenium-, iridium

• . In addition, the film exhibited high methanol and base tolerance making it suitable for applications in fuel cells and anion-conducting devices. Owing to their high phosphorescent propensity, complexes based on iridium have been grafted onto polymers for the application as light-emitting diodes (LEDs

• ) [58]. In an earlier research, in order to obtain iridium-containing polymers by the ROMP route, Weck and coworkers [59] polymerized monomers 29 and mer-31, in the presence of Grubbs 3rd generation catalyst, to the fully soluble ROMP homopolymers 30 and mer-32 (Scheme 13). Later on, while investigating

Enantioselective additions of copper acetylides to cyclic iminium and oxocarbenium ions

• Jixin Liu,
• Srimoyee Dasgupta and
• Mary P. Watson

Beilstein J. Org. Chem. 2015, 11, 2696–2706, doi:10.3762/bjoc.11.290

• -aryltetrahydroisoquinolines with alkynes (Scheme 11) [33]. By using an iridium-based photoredox catalyst in combination with benzoyl peroxide, iminium ion 7 is formed in situ. This strategy enables reduction of the reaction temperature, ultimately enabling higher enantioselectivities. With respect to the scope of alkynes

Rhodium, iridium and nickel complexes with a 1,3,5-triphenylbenzene tris-MIC ligand. Study of the electronic properties and catalytic activities

• Carmen Mejuto,
• Beatriz Royo,
• Gregorio Guisado-Barrios and
• Eduardo Peris

Beilstein J. Org. Chem. 2015, 11, 2584–2590, doi:10.3762/bjoc.11.278

• , Portugal 10.3762/bjoc.11.278 Abstract The coordination versatility of a 1,3,5-triphenylbenzene-tris-mesoionic carbene ligand is illustrated by the preparation of complexes with three different metals: rhodium, iridium and nickel. The rhodium and iridium complexes contained the [MCl(COD)] fragments, while

• addition reaction of arylboronic acids to α,β-unsaturated ketones. Keywords: arylation of unsaturated ketones; mesoionic carbenes; nickel; iridium; rhodium; Introduction Highly symmetrical poly-NHCs are a very interesting type of ligands, because they allow the preparation of a variety of supramolecular

• higher nanolocal concentration of metal sites in the multimetallic catalyst [31]. In this context, we obtained the 1,3,5-triphenylbenzene-based C3-symmetrical tris-NHC ligand A (Scheme 1), which was coordinated to rhodium and iridium [25]. The catalytic activity of the trirhodium complex was tested in

Cu(I)-catalyzed N,N’-diarylation of natural diamines and polyamines with aryl iodides

• Svetlana P. Panchenko,
• Alexei D. Averin,
• Maksim V. Anokhin,
• Olga A. Maloshitskaya and
• Irina P. Beletskaya

Beilstein J. Org. Chem. 2015, 11, 2297–2305, doi:10.3762/bjoc.11.250

• the literature. One of them employs an iridium-based catalyst with amidophosphonate as the ligand which allows to convert aminoalcohols into N-monoaryl-substituted diamines by the reaction with arylamines [20]. Another method uses a bimetallic catalyst (Pt–Sn/γ-Al2O3) in the reactions of diols with