(E,Z)-1,1,1,4,4,4-Hexafluorobut-2-enes: hydrofluoroolefins halogenation/dehydrohalogenation cascade to reach new fluorinated allene

• Nataliia V. Kirij,
• Andrey A. Filatov,
• Yurii L. Yagupolskii,
• Sheng Peng and
• Lee Sprague

Beilstein J. Org. Chem. 2024, 20, 452–459, doi:10.3762/bjoc.20.40

• significantly. One of the new and budding directions in recent years is the stereoselective olefin metathesis processes based on catalysis by complexes of molybdenum, tungsten and ruthenium [3][4][5]. The first publications have recently appeared that molybdenum complexes can catalyze cross-metathesis of butene

Green and sustainable approaches for the Friedel–Crafts reaction between aldehydes and indoles

• Periklis X. Kolagkis,
• Eirini M. Galathri and
• Christoforos G. Kokotos

Beilstein J. Org. Chem. 2024, 20, 379–426, doi:10.3762/bjoc.20.36

Strategies to access the [5-8] bicyclic core encountered in the sesquiterpene, diterpene and sesterterpene series

• Cécile Alleman,
• Charlène Gadais,
• Laurent Legentil and
• François-Hugues Porée

Beilstein J. Org. Chem. 2023, 19, 245–281, doi:10.3762/bjoc.19.23

• ][9]. Metathesis reactions take place by the means of a metallic catalyst. Firstly, olefin metathesis was achieved with an air-sensitive tungsten complex [8]. An important focus on air-stable catalyst design was undertaken and contributed to the popularization of the reaction. Thus, Grubbs catalysts

Highly regio- and stereoselective phosphinylphosphination of terminal alkynes with tetraphenyldiphosphine monoxide under radical conditions

• Dat Phuc Tran,
• Yuki Sato,
• Yuki Yamamoto,
• Shin-ichi Kawaguchi,
• Shintaro Kodama,
• Akihiro Nomoto and
• Akiya Ogawa

Beilstein J. Org. Chem. 2021, 17, 866–872, doi:10.3762/bjoc.17.72

• was produced in 28% yield (Table 1, entry 2). However, 3a was obtained only in trace amounts upon irradiation with a tungsten lamp [51] (Table 1, entry 3). These results indicate that Ph2P• [52][53][54][55] and/or Ph2P(O)• [56][57][58][59] radicals were generated by the irradiation with light in the

One-pot multicomponent green Hantzsch synthesis of 1,2-dihydropyridine derivatives with antiproliferative activity

• Giovanna Bosica,
• Kaylie Demanuele,
• José M. Padrón and
• Adrián Puerta

Beilstein J. Org. Chem. 2020, 16, 2862–2869, doi:10.3762/bjoc.16.235

• reported by Cao and collaborators [19]. Catalyst characterization and recyclability The catalyst was analyzed by X-ray fluorescence (XRF) spectroscopy in order to ascertain the PW/Al2O3-support ratio. The mass percentage ratio of tungsten, which is the main component of the catalyst, and aluminium, the

Heterogeneous photocatalysis in flow chemical reactors

• Christopher G. Thomson,
• Ai-Lan Lee and
• Filipe Vilela

Beilstein J. Org. Chem. 2020, 16, 1495–1549, doi:10.3762/bjoc.16.125

• recombination [154][155]. Suárez and co-workers used the photodeposition of platinum onto tungsten oxide (WO3) powder, before immobilising within a zeolite framework to produce visible light-active HPCats for the degradation of pollutants in air [156]. Scaiano and co-workers have also utilised photodeposition

Formation of alkyne-bridged ferrocenophanes using ring-closing alkyne metathesis on 1,1’-diacetylenic ferrocenes

• Celine Bittner,
• Dirk Bockfeld and
• Matthias Tamm

Beilstein J. Org. Chem. 2019, 15, 2534–2543, doi:10.3762/bjoc.15.246

• of conjugated diynes (DYCM) is promoted by the benzylidyne tungsten complex II with silanolate ligands (X = OSi(Ot-Bu)3) [21][22]; this catalyst is also active in classical alkyne metathesis [23]. Complex III with chelating phenoxide ligands [24][25][26][27] is mostly applied in supramolecular

• recently added tungsten complex [MesC≡W{OC(CH3)2(CF3)}3] (WF3) [45]. Because of the higher electrophilicity of the tungsten metal, the less electron-rich trifluoro-tert-butoxide ligands are sufficient to obtain an active catalyst for the metathesis of terminal alkynes. This reactivity could only lately be

Mechanochemical amorphization of chitin: impact of apparatus material on performance and contamination

• Thomas Di Nardo and
• Audrey Moores

Beilstein J. Org. Chem. 2019, 15, 1217–1225, doi:10.3762/bjoc.15.119

• mechanochemical amorphization of chitin. We measured the crystallinity index of chitin after milling it in a vibration mill in an apparatus made of copper, aluminum, brass, tungsten carbide, zirconia, stainless steel, polytetrafluoroethylene (PTFE), or poly(methyl methacrylate) (PMMA). These materials offer a

• size and mass, while concentration on amorphization performance, measured by powder X-ray diffraction (PXRD). We selected for this study reaction jars made of copper, aluminum, brass, tungsten carbide, zirconia, stainless steel, PTFE, or poly(methyl methacrylate) (PMMA) paired with one ball of the same

• tested: stainless steel (SS), zirconia (ZrO2), copper (Cu), aluminum (Al), brass, tungsten carbide (WC), poly(methyl methacrylate) (PMMA), and polytetrafluoroethylene (PTFE). These media have distinct density; we needed to normalize the resulting experiments. We expected two ball parameters to play a

Catalysis of linear alkene metathesis by Grubbs-type ruthenium alkylidene complexes containing hemilabile α,α-diphenyl-(monosubstituted-pyridin-2-yl)methanolato ligands

• Tegene T. Tole,
• Johan H. L. Jordaan and
• Hermanus C. M. Vosloo

Beilstein J. Org. Chem. 2019, 15, 194–209, doi:10.3762/bjoc.15.19

• (Figure 1). Of course, the role of the so-called Schrock metal carbenes based on tungsten and molybdenum should not be ignored in the success story of the alkene metathesis reaction but it is not the focus of this article. The large number of ruthenium alkylidene precatalysts that has been developed is

Degenerative xanthate transfer to olefins under visible-light photocatalysis

• Atsushi Kaga,
• Xiangyang Wu,
• Joel Yi Jie Lim,
• Hirohito Hayashi,
• Yunpeng Lu,
• Edwin K. L. Yeow and
• Shunsuke Chiba

Beilstein J. Org. Chem. 2018, 14, 3047–3058, doi:10.3762/bjoc.14.283

• dexanthylation of α-xanthyl ketones [17][18][19][20][21]. As an alternative strategy, a light-driven approach has been developed [22][23][24][25][26], since the first degenerative transfer of xanthates using S-benzoyl O-ethyl xanthate as a photo-cleavable initiator under tungsten lamp irradiation was reported by

MoO₃ on zeolites MCM-22, MCM-56 and 2D-MFI as catalysts for 1-octene metathesis

• Hynek Balcar,
• Martin Kubů,
• Naděžda Žilková and
• Mariya Shamzhy

Beilstein J. Org. Chem. 2018, 14, 2931–2939, doi:10.3762/bjoc.14.272

• . Moreover, for related system based on tungsten oxide in zeolite, it was suggested using high resolution STEM that Brønsted acid sites in proximity to metathesis active sites facilitate olefin adsorption and metallocycle formation [29]. Such mechanism may be effective also for Mo catalysts. The decrease in

Learning from B₁₂ enzymes: biomimetic and bioinspired catalysts for eco-friendly organic synthesis

• Keishiro Tahara,
• Ling Pan,
• Toshikazu Ono and
• Yoshio Hisaeda

Beilstein J. Org. Chem. 2018, 14, 2553–2567, doi:10.3762/bjoc.14.232

• vesicles composed of synthetic lipids and alkylated complexes of heptapropyl cobyrinate (Scheme 3) [32][33]. The alkylated B12 model complexes were introduced into the vesicle in aqueous solutions through non-covalent hydrophobic interactions and irradiated with a 500 W tungsten lamp to result in the

• (TEOA) as sacrificial reductant on irradiation with a 500 W tungsten lamp in ethanol. DDT was successfully converted to DDD, DDE, and TTDB (E/Z). The recycled use of 1 and [Ru(bpy)3]Cl2 was also achieved using an ionic liquid as the reaction medium [103]. Recently, we have found that cyclometalated

Efficient catalytic alkyne metathesis with a fluoroalkoxy-supported ditungsten(III) complex

• Henrike Ehrhorn,
• Janin Schlösser,
• Dirk Bockfeld and
• Matthias Tamm

Beilstein J. Org. Chem. 2018, 14, 2425–2434, doi:10.3762/bjoc.14.220

• Henrike Ehrhorn Janin Schlosser Dirk Bockfeld Matthias Tamm Institut für Anorganische und Analytische Chemie, Technische Universität Braunschweig, Hagenring 30, 38106 Braunschweig, Germany 10.3762/bjoc.14.220 Abstract The molybdenum and tungsten complexes M2(OR)6 (Mo2F6, M = Mo, R = C(CF3)2Me

• bimetallic tungsten complex W2F3 and the alkylidyne complex WPhF3. In contrast, Mo2F6 displayed no significant activity in alkyne metathesis. Keywords: alkylidyne complexes; alkyne metathesis; catalysis; terminal alkynes; tungsten; Introduction While the field of olefin metathesis has seen significant

• were initially based on a design strategy inspired by the structure of highly active olefin metathesis catalysts, the Schrock-type molybdenum and tungsten alkylidene complexes [13][14][15]. Imidazolin-2-iminato ligands were used to modify Schrock-type alkylidyne complexes, resulting in new active

The phenyl vinyl ether–methanol complex: a model system for quantum chemistry benchmarking

• Dominic Bernhard,
• Fabian Dietrich,
• Mariyam Fatima,
• Cristóbal Pérez,
• Hannes C. Gottschalk,
• Axel Wuttke,
• Ricardo A. Mata,
• Martin A. Suhm,
• Melanie Schnell and
• Markus Gerhards

Beilstein J. Org. Chem. 2018, 14, 1642–1654, doi:10.3762/bjoc.14.140

• used in combination with a 150 W tungsten filament and an optical filter (4200–2450 cm−1) to maximize the signal-to-noise ratio in the OH stretching range of the vibrational spectra. For the final spectra, 150 to 775 pulses were co-added to further improve signal-to-noise. IR/UV setup The experimental

Is the tungsten(IV) complex (NEt₄)₂[WO(mnt)₂] a functional analogue of acetylene hydratase?

• Matthias Schreyer and
• Lukas Hintermann

Beilstein J. Org. Chem. 2017, 13, 2332–2339, doi:10.3762/bjoc.13.230

• Matthias Schreyer Lukas Hintermann Department Chemie, Technische Universität München, Lichtenbergstr. 4, 85748 Garching bei München, Germany TUM Catalysis Research Center, Ernst-Otto-Fischer-Str. 1, 85748 Garching bei München, Germany 10.3762/bjoc.13.230 Abstract The tungsten(IV) complex (Et4N)2

• regioselectivity of tungsten-catalyzed alkyne hydration of a terminal, higher alkyne had to be determined. However, complex 1 was not a competent catalyst for the hydration of 1-octyne under the conditions tested. Furthermore, we could not observe the earlier reported hydration activity of complex 1 towards

• acetylene. A critical assessment of, and a possible explanation for the earlier reported results are offered. The title question is answered with "no". Keywords: acetylene hydratase; alkynes; catalytic hydration; enzyme models; tungsten complexes; Introduction In 1985, the enzyme acetylene hydratase

Main group mechanochemistry

• Agota A. Gečiauskaitė and
• Felipe García

Beilstein J. Org. Chem. 2017, 13, 2068–2077, doi:10.3762/bjoc.13.204

• the choice of milling media (i.e., the milling jar loaded with one or more ball bearings). For example, milling balls made from denser materials (e.g., 2.3 g·cm−3 vs 15.6 g·cm−3 for Teflon and tungsten carbide, respectively) carry greater kinetic energy during the milling progress. The potential for

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

• materials like stainless steel, tungsten carbide, zirconia, agate, etc. [24]. In the past decade, mechanochemical reactions were developed under the areas of chemistry like supramolecular chemistry [25][26], organic synthesis [27][28], nanoparticle synthesis, etc. [29][30]. The historical development of

Mechanochemical borylation of aryldiazonium salts; merging light and ball milling

• José G. Hernández

Beilstein J. Org. Chem. 2017, 13, 1463–1469, doi:10.3762/bjoc.13.144

• ] and to develop more sustainable syntheses. Typically, mechanochemical reactions by milling are conducted in non-translucent containers (e.g., agate, ceramics, steels, and tungsten carbide). While this diversity of milling media materials enables controlling, for example, the energy input during the

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

• carbodicarbenes [50][51], in which the carbon atom has a formal oxidation state of ±0 (Figure 1) [52][53][54]. Earlier, we had prepared their tungsten and chromium carbonyl complexes, but could not find deviations of the CO stretching frequencies from those of analogous NHC complexes [55]. As this might be due to

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

• Philipp Veit Christoph Forster Katja Heinze Institute of Inorganic and Analytical Chemistry, Johannes Gutenberg-University, Duesbergweg 10-14, 55128 Mainz, Germany 10.3762/bjoc.12.125 Abstract (Aminoferrocenyl)(ferrocenyl)carbene(pentacarbonyl)tungsten(0) (CO)5W=C(NHFc)Fc (W(CO)5(E-2)) is

• mechanistic studies to the formation of imine E-3 are performed by NMR, IR and UV–vis spectroscopy and liquid injection field desorption ionization (LIFDI) mass spectrometry as well as by trapping experiments for low-coordinate tungsten complexes with triphenylphosphane. W(CO)5(E-2) decays thermally in a

• dissociation, followed by an oxidative addition/pseudorotation/reductive elimination pathway with short-lived, elusive seven-coordinate hydrido tungsten(II) intermediates cis(N,H)-W(CO)4(H)(Z-15) and cis(C,H)-W(CO)4(H)(Z-15). Keywords: carbene complexes; ferrocene; imine; mechanism; tungsten; Introduction

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

• insertion to form the caged cyclopropyl ring system in 120. Alternatively, the proximity of the methylene of the benzyl ether in 123 allows for a benzylic C–H insertion to generate the bridged polycycle 124. Tungsten Iwasawa demonstrated a similar strategy for bridged-polycycle synthesis using a tungsten

• catalyst (Scheme 27) [102][103]. Again, the formation of a 1,3-dipole (see 127) allows for a cycloaddition, though this example is intermolecular in nature. One of the ethereal ethyl groups in 128 is consequently poised for C–H bond insertion by the tungsten carbene to give 129 as a single diastereomer

• . 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.

Preparation of Pickering emulsions through interfacial adsorption by soft cyclodextrin nanogels

• Shintaro Kawano,
• Toshiyuki Kida,
• Mitsuru Akashi,
• Hirofumi Sato,
• Motohiro Shizuma and
• Daisuke Ono

Beilstein J. Org. Chem. 2015, 11, 2355–2364, doi:10.3762/bjoc.11.257

• kV. Each Pickering emulsion sample was dried directly onto carbon tape and allowed to dry overnight before being sputter-coated with a thin layer of tungsten. Transmittance electron microscopy (TEM) studies were performed using a JEOL JEM-2100 operating at a voltage of 50 kV in order to clarify the

Thermal properties of ruthenium alkylidene-polymerized dicyclopentadiene

• Yuval Vidavsky,
• Yotam Navon,
• Yakov Ginzburg,
• Moshe Gottlieb and
• N. Gabriel Lemcoff

Beilstein J. Org. Chem. 2015, 11, 1469–1474, doi:10.3762/bjoc.11.159

• be disrupted first to afford a linear polymer, followed by the ring opening of the less reactive cyclopentene double bond to effectively cross-link the chains (Scheme 1). Notably, with tungsten and molybdenum initiators the linear polymer may be isolated [20][21]; unlike the case with ruthenium

The Shono-type electroorganic oxidation of unfunctionalised amides. Carbon–carbon bond formation via electrogenerated N-acyliminium ions

• Alan M. Jones and
• Craig E. Banks

Beilstein J. Org. Chem. 2014, 10, 3056–3072, doi:10.3762/bjoc.10.323

• is attached either to the carbamate or amide (Figure 5) [69][70][71] (using a platinum anode and tungsten cathode electrochemical set-up) [69] or the use of Cu-PyBox chiral ligand systems [72]. The cation pool method can be adapted to a multicomponent reaction (MCR) when an N-acyliminium ion is

Molecular ordering at electrified interfaces: Template and potential effects

• Thanh Hai Phan and
• Klaus Wandelt

Beilstein J. Org. Chem. 2014, 10, 2243–2254, doi:10.3762/bjoc.10.233

• corresponding CV data. The whole experimental setup is home-built and described in detail in [25]. The tunneling tips used in all experiments were electrochemically etched from 0.25 mm in diameter tungsten wire in 2 mM KOH solution, rinsed with high purity water, dried and subsequently insulated by passing them