The effect of milling frequency on a mechanochemical organic reaction monitored by in situ Raman spectroscopy

• Patrick A. Julien,
• Ivani Malvestiti and
• Tomislav Friščić

Beilstein J. Org. Chem. 2017, 13, 2160–2168, doi:10.3762/bjoc.13.216

• Bruker Vertex 70 FT-IR Platinum ATR, while X-ray powder diffraction patterns were collected on a Proto Manufacturing AXRD Benchtop Powder Diffractometer using Ni-filtered Cu Kα radiation. The conversion for each solid-state reaction was evaluated after milling using 1H NMR spectroscopy conducted in CDCl3

Solid-state studies and antioxidant properties of the γ-cyclodextrin·fisetin inclusion compound

• Joana M. Pais,
• Maria João Barroca,
• Maria Paula M. Marques,
• Filipe A. Almeida Paz and
• Susana S. Braga

Beilstein J. Org. Chem. 2017, 13, 2138–2145, doi:10.3762/bjoc.13.212

• continuous mode in the 3.5° ≤ 2θ ≤ 50° interval. TG studies were performed on a Shimadzu TGA-50 thermogravimetric analyzer, using a heating rate of 5 °C min−1, under air atmosphere, with a flow rate of 20 mL min−1. The sample holder was a 5 mm in diameter platinum plate and the sample mass was about 5 mg

An effective Pd nanocatalyst in aqueous media: stilbene synthesis by Mizoroki–Heck coupling reaction under microwave irradiation

• Carolina S. García,
• Paula M. Uberman and
• Sandra E. Martín

Beilstein J. Org. Chem. 2017, 13, 1717–1727, doi:10.3762/bjoc.13.166

• reactions has been reported, using a phase-transfer agent and focusing on the employment of ultralow catalyst concentrations [45]. Recently, we reported the electrochemical synthesis of stable Pd NPs by using platinum or vitreous carbon electrodes at room temperature via direct electroreduction of aqueous

• -Pd NPs of a mean diameter of 10 nm were obtained using a platinum electrode, characterized as previously reported, and used without additional purification [46][47]. In a previous work the PVP-Pd NPs synthesized using a vitreous carbon electrode were tested on the Mizoroki–Heck reaction with 4-iodo

• the stabilizing agent under solution stirring. The galvanostatic synthesis of Pd NPs was performed by applying to the platinum electrode a current density pulse from 0 to a cathodic value of 150 mA/cm2, during 600 s. Vigorous stirring of the solution (1000 rpm) with a magnetic stirrer was kept during

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

• 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

• dehydrogenation of tetrahydroisoquinolines. Ruthenium-catalyzed polycyclic heteroarenes. Plausible mechanism of the ruthenium-catalyzed dehydrogenation. Bi-metallic platinum/iridium alloyed nanoclusters and 5,5’,6,6’-tetrahydroxy-3,3,3’,3’-tetramethyl-1,1’-spiro-bisindane (TTSBI) for the synthesis of quinazolines

Synthesis of alkynyl-substituted camphor derivatives and their use in the preparation of paclitaxel-related compounds

• M. Fernanda N. N. Carvalho,
• Rudolf Herrmann and
• Gabriele Wagner

Beilstein J. Org. Chem. 2017, 13, 1230–1238, doi:10.3762/bjoc.13.122

• platinum(II). The formed product structures depend not only on the reagents used but also on the substituents attached to the triple bonds. Cycloisomerisations with perfect atom economy lead to polycyclic heterocycles that resemble to some extent the AB ring system of paclitaxel. Herein, we present

• ; platinum; Introduction Enantiomerically pure raw materials, available in a sustainable manner from the natural “chiral pool” [1], offer a convenient entrance for the chemical synthesis of other chiral compounds, e.g., rare natural products and their analogues [2], or chiral catalysts [3][4]. A prominent

• leading to a product resembling paclitaxel to some extent was found in both cases. However, one of the isomers yielded a second product lacking the ring-enlargement step and containing an additional sulphur–oxygen–carbon linkage. The platinum complex of this compound was postulated before as an

Glyco-gold nanoparticles: synthesis and applications

• Federica Compostella,
• Olimpia Pitirollo,
• Alessandro Silvestri and
• Laura Polito

Beilstein J. Org. Chem. 2017, 13, 1008–1021, doi:10.3762/bjoc.13.100

• , hosting methotrexate (MTX), an anticancer drug. The anticancer therapy based on platinum compounds, such as cisplatin, carboplatin and oxaliplatin, has many positive effects on the regression of cancer cell proliferation. Unfortunately these compounds are low tolerated by the organisms, therefore new

Continuous-flow processes for the catalytic partial hydrogenation reaction of alkynes

• Carmen Moreno-Marrodan,
• Francesca Liguori and
• Pierluigi Barbaro

Beilstein J. Org. Chem. 2017, 13, 734–754, doi:10.3762/bjoc.13.73

• alternative to palladium, a 1 wt % platinum catalyst supported onto calcium carbonate was also reported, however, with no practical advantages over Pd in terms of partial hydrogenation (27% ene selectivity at 78% conversion and 373 K) [173]. Methyl phenylpropiolate and 4-phenyl-3-butyn-2-one The continuous

Diastereoselective anodic hetero- and homo-coupling of menthol-, 8-methylmenthol- and 8-phenylmenthol-2-alkylmalonates

• Matthias C. Letzel,
• Hans J. Schäfer and
• Roland Fröhlich

Beilstein J. Org. Chem. 2017, 13, 33–42, doi:10.3762/bjoc.13.5

• anodic decarboxylation of five malonic acid derivatives. These were prepared from benzyl malonates and four menthol auxiliaries. Coelectrolyses with 3,3-dimethylbutanoic acid in methanol at platinum electrodes in an undivided cell afforded hetero-coupling products in 22–69% yield with a

• purity (Scheme 1). Anodic hetero-coupling of carboxylates Carboxylates of aliphatic carboxylic acids are oxidized to carbonyloxy radicals at a platinum electrode at potentials being generally higher than 2.0 V (vs NHE). The carbonyloxy radicals undergo fast decarboxylation to alkyl radicals at or near

• for constant temperature control, capacity: 3 mL (micro beaker-type cell). Platinum foils serving as anode and cathode materials (platinum foils: 1 × 1 cm). Convection was achieved by magnetic stirring. Current source: Heinzinger galvanostat – potentiostat HN 600–600 and TNs 300–1500. General

Organometallic chemistry

• Bernd F. Straub,
• Rolf Gleiter,
• Claudia Meier and
• Lutz H. Gade

Beilstein J. Org. Chem. 2016, 12, 2216–2221, doi:10.3762/bjoc.12.213

• -butylphosphino)methane (dtbpm) were a unique feature of his work [61][67][70][71][72][80][81][84][86][93][94][97][100][101][103][107][124][128][148][149] that ultimately enabled C–Si activation of organosilanes and the C–C activation of oxiranes by coordinatively unsaturated platinum species [66][149]. In the

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

• result in no reaction, the optimized catalyst was used with an external source of triphenylphosphine, which resulted in no reaction (Table 1, entry 12). To expand the scope of catalyst, the effect of using a platinum catalyst was investigated. The use of a platinum(IV) catalyst resulted in no reaction

• (Table 1, entry 13) along with the use of a platinum(II) catalyst (Table 1, entry 14). Using an anionic platinum(II) catalyst yielded substituted naphthalene 11a in a 22% yield, though this was considerably lower when compared to the optimized palladium catalyst. A variety of solvents were next screened

Solvent-free synthesis of novel para-menthane-3,8-diol ester derivatives from citronellal using a polymer-supported scandium triflate catalyst

• Lubabalo Mafu,
• Ben Zeelie and
• Paul Watts

Beilstein J. Org. Chem. 2016, 12, 2046–2054, doi:10.3762/bjoc.12.193

• gas. The samples were analysed by using the following method; injector temperature 250 °C, helium flow rate 0.1 mL·min−1, oven temperature 70 °C for 5 min and then ramped to 280 °C at 10 °C min−1 with split flow ratio of 60 mL·min−1. The FTIR characteristic peaks were recorded on a Bruker Platinum

Synthesis and characterization of fluorinated azadipyrromethene complexes as acceptors for organic photovoltaics

• Forrest S. Etheridge,
• Roshan J. Fernando,
• Sandra Pejić,
• Matthias Zeller and
• Geneviève Sauvé

Beilstein J. Org. Chem. 2016, 12, 1925–1938, doi:10.3762/bjoc.12.182

• tetra-n-butylammonium hexafluorophosphate (TBAPF6) in DCM. Ferrocene/ferrocenium was used as an internal standard and was purified prior to use by sublimation. A typical three-electrode configuration was used, with a glassy carbon electrode as the working electrode and two platinum wires used as the

Synthesis and properties of fluorescent 4′-azulenyl-functionalized 2,2′:6′,2″-terpyridines

• Adrian E. Ion,
• Liliana Cristian,
• Mariana Voicescu,
• Masroor Bangesh,
• Augustin M. Madalan,
• Daniela Bala,
• Constantin Mihailciuc and
• Simona Nica

Beilstein J. Org. Chem. 2016, 12, 1812–1825, doi:10.3762/bjoc.12.171

• measurements were carried out on a potentiostat-galvanostat system AutoLabPGStat 12, controlled by GPES (general purpose electrochemical system) electrochemical interface for Windows (version 4.9.007). Three electrodes in an one-compartment cell (10 mL) were used in all experiments. A platinum disk electrode

Synthesis and characterization of benzodithiophene and benzotriazole-based polymers for photovoltaic applications

• Desta Gedefaw,
• Marta Tessarolo,
• Margherita Bolognesi,
• Mario Prosa,
• Renee Kroon,
• Wenliu Zhuang,
• Patrik Henriksson,
• Kim Bini,
• Ergang Wang,
• Michele Muccini,
• Mirko Seri and
• Mats R. Andersson

Beilstein J. Org. Chem. 2016, 12, 1629–1637, doi:10.3762/bjoc.12.160

• -Instruments 650A Electrochemical Workstation. As described in [27], a three-electrode setup consisting of platinum wires, both as working electrode and counter electrode, and a Ag/Ag+ quasi reference electrode were used. A 0.1 M solution of tetrabutylammonium hexafluorophosphate (Bu4NPF6) in anhydrous

Methylpalladium complexes with pyrimidine-functionalized N-heterocyclic carbene ligands

• Dirk Meyer and
• Thomas Strassner

Beilstein J. Org. Chem. 2016, 12, 1557–1565, doi:10.3762/bjoc.12.150

• stoichiometric reactions. The Shilov system [12][13][14][15][16][17], had the disadvantage of using stoichiometric amounts of platinum for the reoxidation of the active catalyst and the platinum bispyrimidine system [18][19][20] was not successful because of the large amounts of diluted sulfuric acids as the

• “Catalytica” bispyrimidine system, for the biscarbene system the palladium complexes turned out to be more stable than the corresponding platinum complexes under the reaction conditions [31][32], although Peter Hofmann had recently shown the stability and reactivity of the platinum-alkyl complexes with bis

• -NHC ligand [33]. To study the differences between both systems we synthesized palladium [34] and platinum [35] “hybrid complexes” with ligands combining both structural elements the pyrimidine as well as the NHC fragment. We also used density functional theory (DFT) calculations to investigate the

Stereodynamic tetrahydrobiisoindole “NU-BIPHEP(O)”s: functionalization, rotational barriers and non-covalent interactions

• Golo Storch,
• Sebastian Pallmann,
• Frank Rominger and
• Oliver Trapp

Beilstein J. Org. Chem. 2016, 12, 1453–1458, doi:10.3762/bjoc.12.141

• ][6], palladium [7][8], platinum [9][10] and gold [11][12][13] in combination with chiral co-ligands or counter ions that are used after alignment of the ligand’s axial chirality. One major advantage of stereodynamic ligands is that there is no need for separate preparation of one ligand enantiomer as

Ring-whizzing in polyene-PtL₂ complexes revisited

• Oluwakemi A. Oloba-Whenu,
• Thomas A. Albright and
• Chirine Soubra-Ghaoui

Beilstein J. Org. Chem. 2016, 12, 1410–1420, doi:10.3762/bjoc.12.135

• cyclopentadienyl-platinum-bis(diphenylphosphinobiphenyl) [39] there are two Pt–C distances at 2.26(1) Å and one at 2.33(1) Å. The conformation of the PtL2 unit with respect to the Cp ring is approximately that given by 13. Accordingly, the remaining two Pt–C distances are 2.37(1) Å. For optimized 13 the

Reactivity studies of pincer bis-protic N-heterocyclic carbene complexes of platinum and palladium under basic conditions

• David C. Marelius,
• Curtis E. Moore,
• Arnold L. Rheingold and
• Douglas B. Grotjahn

Beilstein J. Org. Chem. 2016, 12, 1334–1339, doi:10.3762/bjoc.12.126

• .12.126 Abstract Bis-protic N-heterocyclic carbene complexes of platinum and palladium (4) yield dimeric structures 6 when treated with sodium tert-butoxide in CH2Cl2. The use of a more polar solvent (THF) and a strong base (LiN(iPr)2) gave the lithium chloride adducts monobasic complex 7 or analogous

• dibasic complex 8. Keywords: NHC; 15N NMR spectroscopy; palladium; platinum; protic N-heterocyclic carbene; Introduction N-Heterocyclic carbenes (NHCs) have been extensively researched for a number of purposes since 1991 when Arduengo first isolated free NHCs [1][2][3]. NHCs as ligands have been known

• occupied by an imidazolyl nitrogen from a second complex (Figure 2). The palladium and platinum dimer complexes, 6-Pd and 6-Pt, could be formed by addition of sodium tert-butoxide to the chloride analogs (Scheme 1), and isolated in 50–56% yields. The examination of the dimer crystal structure (see Figure 2

On the mechanism of imine elimination from Fischer tungsten carbene complexes

• Philipp Veit,
• Christoph Förster and
• Katja Heinze

Beilstein J. Org. Chem. 2016, 12, 1322–1333, doi:10.3762/bjoc.12.125

• versus external H3PO4 (85%) (31P: δ = 0 ppm). IR spectra were recorded with a BioRad Excalibur FTS 3100 spectrometer as KBr disks or by using KBr cells in CH2Cl2 or in CD2Cl2. Electrochemical experiments were carried out on a BioLogic SP-50 voltammetric analyzer by using a platinum working electrode, a

• platinum wire as counter electrode and a 0.01 M Ag/AgNO3 electrode as reference electrode. The measurements were carried out at a scan rate of 100 mV s−1 for cyclic voltammetry experiments and at 50 mV s−1 for square wave voltammetry experiments in 0.1 M [n-Bu4N][B(C6F5)4] as supporting electrolyte in THF

Conjugate addition–enantioselective protonation reactions

• James P. Phelan and
• Jonathan A. Ellman

Beilstein J. Org. Chem. 2016, 12, 1203–1228, doi:10.3762/bjoc.12.116

• methacrylonitrile (Figure 4) [70][71][72][73][74]. Other researchers have reported platinum [75], nickel [76], and zirconium [77] catalysts for the hydrophosphination and hydroamination of methacrylonitrile; however, these examples provided product with significantly lower enantioselectivity. In 2004, the Togni lab

The synthesis of functionalized bridged polycycles via C–H bond insertion

• Jiun-Le Shih,
• Po-An Chen and
• Jeremy A. May

Beilstein J. Org. Chem. 2016, 12, 985–999, doi:10.3762/bjoc.12.97

• ) [98]. Here, a single gold species was used that contained a sterically bulky t-Bu-XPhos ligand. Many examples of the synthesis of ring-fused bridged bicycles were shown in a very nice demonstration of the reaction. Platinum Recent examples have used less common metals as catalysts for C–H bond

• insertion. Oh used platinum to generate intermediate 1,3-dipoles like 118 and 122, which then undergo a cycloaddition to generate 119 or 123, respectively (Scheme 26) [99][100][101]. Here, the reactivity of those carbenes diverges. Carbene 119, which has a distal benzyl ether, undergoes a methine C–H bond

• . Platinum cascades. Tungsten cascade. Acknowledgements The authors are grateful to the Welch Foundation (grant E-1744) and the NSF (grant CHE-1352439) for financial support. J-L.S. is grateful for support by CBIP (UH) and the Studying Abroad Scholarship of Taiwan.

Bi- and trinuclear copper(I) complexes of 1,2,3-triazole-tethered NHC ligands: synthesis, structure, and catalytic properties

• Shaojin Gu,
• Jiehao Du,
• Jingjing Huang,
• Huan Xia,
• Ling Yang,
• Weilin Xu and
• Chunxin Lu

Beilstein J. Org. Chem. 2016, 12, 863–873, doi:10.3762/bjoc.12.85

• and platinum complexes containing 1,2,3-triazole-tethered NHC ligands. The obtained palladium complexes displayed high activity in aqueous Suzuki–Miyaura cross-coupling reactions. We are interested in the synthesis and use of functionalized NHC ligands [20][28][29][30][31]. Herein, the synthesis

Interactions between 4-thiothymidine and water-soluble cyclodextrins: Evidence for supramolecular structures in aqueous solutions

• Vito Rizzi,
• Sergio Matera,
• Paola Semeraro,
• Paola Fini and
• Pinalysa Cosma

Beilstein J. Org. Chem. 2016, 12, 549–563, doi:10.3762/bjoc.12.54

• /AgCl, Cl− (saturated KCl) and a platinum wire. In our experiments, the working electrode was polished with alumina and washed with water before each experiment. In detail, the glassy carbon electrode was first rinsed with tap water, followed by a methanol rinse and carefully wiped dry with a fresh lab

Study on the synthesis of the cyclopenta[f]indole core of raputindole A

• Nils Marsch,
• Mario Kock and
• Thomas Lindel

Beilstein J. Org. Chem. 2016, 12, 334–342, doi:10.3762/bjoc.12.36

• indoline and changing the N-protecting group significantly improved the yield for the cyclocitral adduct, but this still does not appear to be sufficient for a strategy towards raputindole A (1). Cyclization of propargylacetates. Key progress came when applying platinum and gold chemistry to

Supramolecular polymer assembly in aqueous solution arising from cyclodextrin host–guest complexation

• Jie Wang,
• Zhiqiang Qiu,
• Yiming Wang,
• Li Li,
• Xuhong Guo,
• Duc-Truc Pham,
• Stephen F. Lincoln and
• Robert K. Prud’homme

Beilstein J. Org. Chem. 2016, 12, 50–72, doi:10.3762/bjoc.12.7

• ]. In the first stage, the two chloro ligands on the four-coordinate square-planar platinum(II) center of cisplatin are displaced by PEG-b-PAA carboxylate groups to produce PEG-b-PAA-cisplatin micelles. Addition of α-CD results in host–guest complexation of the PEG segments of PEG-b-PAA and subsequent