Selective ring-opening metathesis polymerization (ROMP) of cyclobutenes. Unsymmetrical ladderphane containing polycyclobutene and polynorbornene strands

• Yuan-Zhen Ke,
• Shou-Ling Huang,
• Guoqiao Lai and
• Tien-Yau Luh

Beilstein J. Org. Chem. 2019, 15, 44–51, doi:10.3762/bjoc.15.4

• (Figures S8–S10). The rate constants were thus obtained (Figures S1 and S2). Strategy for sequential ROMP of 1 to yield 3. ROMP of 4 and 5 in THF at 0 °C in the presence of 10 mol % of 6. Retrosynthesis of 8 from 9. Synthesis of monomer 9. Synthesis of 14 and 8 by selective olefin metathesis

Ruthenium-based olefin metathesis catalysts with monodentate unsymmetrical NHC ligands

• Veronica Paradiso,
• Chiara Costabile and
• Fabia Grisi

Beilstein J. Org. Chem. 2018, 14, 3122–3149, doi:10.3762/bjoc.14.292

• Veronica Paradiso Chiara Costabile Fabia Grisi Dipartimento di Chimica e Biologia “Adolfo Zambelli”, Università di Salerno, Via Giovanni Paolo II 132, I-84084 Fisciano, Salerno, Italy 10.3762/bjoc.14.292 Abstract An overview on the catalytic properties of ruthenium complexes for olefin metathesis

• bearing monodentate unsymmetrical N-heterocyclic diaminocarbene ligands is provided. The non-symmetric nature of these NHC architectures strongly influences activity and selectivity of the resulting catalysts. The main achievements that have been accomplished in significant areas of olefin metathesis up

• to the current state of research are discussed. Keywords: ligand design; olefin metathesis; ruthenium catalysts; selectivity; unsymmetrical N-heterocyclic carbenes; Introduction The transition metal-catalyzed olefin metathesis reaction is an indispensable synthetic tool for the construction of new

A tutorial review of stereoretentive olefin metathesis based on ruthenium dithiolate catalysts

• Daniel S. Müller,
• Olivier Baslé and
• Marc Mauduit

Beilstein J. Org. Chem. 2018, 14, 2999–3010, doi:10.3762/bjoc.14.279

• Daniel S. Muller Olivier Basle Marc Mauduit Univ. Rennes, Ecole Nationale Supérieure de Chimie de Rennes, CNRS, ISCR – UMR 6226, F-35000 Rennes, France 10.3762/bjoc.14.279 Abstract Stereoretentive olefin metathesis based on ruthenium dithiolate complexes has become a very active field of research

• dithiolate catalysts in a logic manner, thus providing an "operators handbook" for chemists who wish to apply this methodology in synthesis. Keywords: catalysis; olefin metathesis; ruthenium; stereoretentive; Review 1 Catalyst discovery and structure optimization from 2013–2018 In stereoretentive

• where it was 5 years ago and certainly further important improvements will be reported in the near future. Most efficient Ru-dithiolate catalysts for stereoretentive olefin metathesis with Z- and E-alkenes as starting materials (activity increases from left to right). Selected examples of sterically or

Ring-closing-metathesis-based synthesis of annellated coumarins from 8-allylcoumarins

• Christiane Schultze and
• Bernd Schmidt

Beilstein J. Org. Chem. 2018, 14, 2991–2998, doi:10.3762/bjoc.14.278

• /cyclization sequence. They serve as a versatile platform for the annellation of five- to seven-membered rings using ring-closing olefin metathesis (RCM). Furano-, pyrano-, oxepino- and azepinocoumarins were synthesized from the same set of precursors using Ru-catalyzed double bond isomerizations and RCM in a

• contribution we report how 8-allylcoumarins obtained through the microwave-promoted tandem sequence can be elaborated into heteroannellated coumarins that are either natural products or close ring-expanded analogues, using ring-closing olefin metathesis (RCM) reactions. Precedence for the use of RCM [40] in

• the synthesis and functionalization of coumarins is scarce, considering the vast number of applications olefin metathesis has found [41] and taking into account the high relevance of coumarins. Construction of the coumarin by RCM has been reported by few groups [42][43][44][45] and heteroannellations

The activity of indenylidene derivatives in olefin metathesis catalysts

• Maria Voccia,
• Steven P. Nolan,
• Luigi Cavallo and
• Albert Poater

Beilstein J. Org. Chem. 2018, 14, 2956–2963, doi:10.3762/bjoc.14.275

• turnover event of an olefin metathesis reaction using a new family of homogenous Ru-based catalysts bearing modified indenylidene ligands has been investigated, using methoxyethylene as a substrate. The study is carried out by means of density functional theory (DFT). The indenylidene ligands are decorated

• significant role. Keywords: activation; IMes; indenylidene; olefin metathesis; SIMes; Introduction Olefin metathesis has been an intensely studied reaction due to its wide use [1], in industrial applications, especially in petrochemistry [2], i.e., the Phillips Triolefin (PTP) process or the Shell Higher

• Olefin Process (SHOP) [3][4]. Additionally, the olefin metathesis reaction has provided a useful tool in polymerisation [5][6], as well as in the pharmaceutical industry in the formation of C=C bonds. Early catalyst examples were ill-defined entities and it is not until Grubbs [7] and Schrock [8

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

• Hynek Balcar Martin Kubu Nadezda Zilkova Mariya Shamzhy J. Heyrovský Institute of Physical Chemistry of the Czech Academy of Sciences, v.v.i., Dolejškova 3, 182 23 Prague 8, Czech Republic 10.3762/bjoc.14.272 Abstract Highly active olefin metathesis catalysts were prepared by thermal spreading

The influence of the cationic carbenes on the initiation kinetics of ruthenium-based metathesis catalysts; a DFT study

• Magdalena Jawiczuk,
• Angelika Janaszkiewicz and
• Bartosz Trzaskowski

Beilstein J. Org. Chem. 2018, 14, 2872–2880, doi:10.3762/bjoc.14.266

• steric and electronic properties can be easily controlled and tuned to obtain very efficient and specific catalysts. One of the most successful uses of NHCs in catalysis is the olefin metathesis, which nowadays became one of the most commonly used tool in modern synthesis [8][9][10]. The vast popularity

• ligands have been synthesized and used in catalysis [19][20][21]. With respect to olefin metathesis cationic carbenes have been introduced as early as in 2007, where Grubbs described the first ammonium-tagged Hoveyda-type catalyst [22]. The goal of that study was to develop systems that are active and

• been observed by us earlier in carbene dimers formation, where mesityl groups, which usually act as weakly electron-donating moieties, could also accommodate a substantial amount of excess negative or positive charge [49]. Conclusion Despite hundreds of examples of ruthenium-based olefin metathesis

Olefin metathesis catalysts embedded in β-barrel proteins: creating artificial metalloproteins for olefin metathesis

• Daniel F. Sauer,
• Johannes Schiffels,
• Takashi Hayashi,
• Ulrich Schwaneberg and
• Jun Okuda

Beilstein J. Org. Chem. 2018, 14, 2861–2871, doi:10.3762/bjoc.14.265

• , Graduate School of Engineering, Osaka University, 2-1 Yamadaoka, Suita 565-0871, Japan 10.3762/bjoc.14.265 Abstract This review summarizes the recent progress of Grubbs–Hoveyda (GH) type olefin metathesis catalysts incorporated into the robust fold of β-barrel proteins. Anchoring strategies are discussed

• and challenges and opportunities in this emerging field are shown from simple small-molecule transformations over ring-opening metathesis polymerizations to in vivo olefin metathesis. Keywords: artificial metalloprotein; β-barrel protein; metathease; olefin metathesis; ruthenium; Introduction Olefin

• ]. According to the Chauvin mechanism, the catalytically active species are Schrock-type carbenes or alkylidenes [2]. Olefin metathesis greatly profited from the isolation of structurally well-defined metal alkylidene complexes [3][4]. The best studied and most commonly employed catalysts are based on Mo, W

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

• 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

Cobalt-catalyzed nucleophilic addition of the allylic C(sp³)–H bond of simple alkenes to ketones

• Tsuyoshi Mita,
• Masashi Uchiyama,
• Kenichi Michigami and
• Yoshihiro Sato

Beilstein J. Org. Chem. 2018, 14, 2012–2017, doi:10.3762/bjoc.14.176

• involving catalytic C–C bond construction with the double bond of terminal alkenes (e.g., Heck reaction, hydrometalation followed by functionalization, carbometalation, and olefin metathesis) [10][11][12][13]. However, direct C–C bond formation of the allylic C(sp3)–H bond adjacent to double bonds has

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

• . Importantly catalytic application of these mechano-synthesized complexes are also explored. Friščić and co-workers recently reported an efficient mechanochemical approach towards Ru-based Hoveyda–Grubbs catalyzed olefin metathesis, cross-metathesis and ring-closing metathesis reactions (Scheme 49) [181

• complex [180]. Mechanochemical Ru-catalyzed olefin metathesis reaction [181]. Rhodium(III)-catalyzed C–H bond functionalization under mechanochemical conditions [182]. Mechanochemical Csp2–H bond amidation using Ir(III) catalyst [183]. Mechanochemical Rh-catalyzed Csp2–X bond formation [184

The chemistry and biology of mycolactones

• Matthias Gehringer and
• Karl-Heinz Altmann

Beilstein J. Org. Chem. 2017, 13, 1596–1660, doi:10.3762/bjoc.13.159

• principal approaches have been used to establish the 12-membered macrolactone ring, namely (1) ring-closure by macrolactonization, the approach followed by Kishi, Negishi and Aggarwal, or (2) ring-closing olefin metathesis (RCM) to form the C8–C9 double bond, which is part of Burkart’s and Altmann’s

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

• for olefin metathesis catalysis [86][87][90][91][98][99][100][108][132][138][147], the characterization of copper–carbene complexes as intermediates in the cyclopropanation of alkenes [102][106][113][119][120], as well as detailed studies into the mechanism of the hydroformylation of alkenes. An

Artificial Diels–Alderase based on the transmembrane protein FhuA

• Hassan Osseili,
• Daniel F. Sauer,
• Klaus Beckerle,
• Marcus Arlt,
• Tomoki Himiyama,
• Tino Polen,
• Akira Onoda,
• Ulrich Schwaneberg,
• Takashi Hayashi and
• Jun Okuda

Beilstein J. Org. Chem. 2016, 12, 1314–1321, doi:10.3762/bjoc.12.124

• metal complexes As the protein host, the FhuA ΔCVFtev variant of the Ferric hydroxamate uptake protein component A (FhuA) was chosen [31]. This protein was shown to be suitable to harbor Grubbs–Hoveyda type catalysts for olefin metathesis [17][18]. To anchor Cu(I) in the protein FhuA ΔCVFtev that

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

• independently by Hashimoto [65][66] and Kan [67] based on an enantioselective intramolecular rhodium carbenoid insertion into C(sp3)–H bonds. In 2012, Pavlyuk and coworkers performed the synthesis of azacycloalkenes by rhodium carbenoid insertion into C(sp3)–H bonds, and subsequent ring closing olefin

• metathesis (RCM) [68]. The insertion of the rhodium carbenoids derived from vinyl diazoacetate into the C(sp3)–H bonds of the alkenylcarbamates 97a–d yields two reaction products (Table 10). The major one (99a–d) was the result of the cyclopropanation reaction of the double bond present in 97a–d. The minor

Simple activation by acid of latent Ru-NHC-based metathesis initiators bearing 8-quinolinolate co-ligands

• Julia Wappel,
• Roland C. Fischer,
• Luigi Cavallo,
• Christian Slugovc and
• Albert Poater

Beilstein J. Org. Chem. 2016, 12, 154–165, doi:10.3762/bjoc.12.17

• behavior in ROMP and especially for their use in the synthesis of poly(dicyclopentadiene) (pDCPD). Bearing either the common phosphine leaving ligand in the first and second Grubbs olefin metathesis catalysts, or the Ru–O bond cleavage for the next Hoveyda-type catalysts, this work is a step forward

• prepared polymers [13][14][15]. Focusing on the origin of organic synthesis, basically based on reactions that drive to the formation of carbon–carbon bonds [16], olefin metathesis turns out to be one potential route to get unsaturated molecules bearing C–C double bonds [17][18][19][20][21], thus by

• extension polymers, as well. Olefin metathesis polymerizations are transition metal-mediated processes which emerged as powerful alternatives to these conventional polymerization methods [22][23]. Thus, it is not surprising that a series of latent but triggerable initiators have been disclosed in the last

Effective immobilisation of a metathesis catalyst bearing an ammonium-tagged NHC ligand on various solid supports

• Krzysztof Skowerski,
• Jacek Białecki,
• Stefan J. Czarnocki,
• Karolina Żukowska and
• Karol Grela

Beilstein J. Org. Chem. 2016, 12, 5–15, doi:10.3762/bjoc.12.2

• metathesis and subsequent reduction of the obtained double bond in one pot. Keywords: catalysis; immobilisation; N-heterocyclic carbenes; olefin metathesis; ruthenium; Introduction Over the past decade olefin metathesis has undergone a grand development. The design of stable and active ruthenium-based

• metathesis catalysts has been the cardinal factor to distribute olefin metathesis in the synthesis of many important compounds [1][2][3][4]. Commercially available homogeneous complexes, including phosphine-containing Gru-II, Ind-II or phosphine-free Hov-II and Gre-II are usually employed in such cases

• commercial Hoveyda complexes have good solubility in methylene chloride (CH2Cl2) and toluene, olefin metathesis reactions with these systems have to be conducted in pentane or hexane. Recently we have reported on the synthesis and catalytic activity of a series of olefin metathesis catalysts bearing a

New metathesis catalyst bearing chromanyl moieties at the N-heterocyclic carbene ligand

• Agnieszka Hryniewicka,
• Szymon Suchodolski,
• Agnieszka Wojtkielewicz,
• Jacek W. Morzycki and
• Stanisław Witkowski

Beilstein J. Org. Chem. 2015, 11, 2795–2804, doi:10.3762/bjoc.11.300

• compounds even at 0 °C. It was also examined in more demanding systems such as conjugated dienes and polyenes. The catalyst is stable, storable and easy to purify. Keywords: chromane derivatives; metathesis catalyst; nitrogen heterocycles; olefin metathesis; Ru-carbene; Introduction Olefin metathesis is

• of organic chemistry since 1992, when Grubbs discovered the first well-defined ruthenium catalyst [2]. Nearly 400 ruthenium heterocyclic carbene-coordinated olefin metathesis catalysts were prepared until 2010 [3]. Since 2011, when Grubbs reported the synthesis of a Z-selective catalyst [4], several

• olefin metathesis catalyst 9 is reported. The catalyst contains a NHC ligand generated from the imidazolinium salt 14 bearing two symmetrically substituted 6-chromanyl moieties. The catalyst 9 was tested in model CM and RCM reactions and showed an activity comparable or superior to that of the commercial

Efficient synthetic protocols for the preparation of common N-heterocyclic carbene precursors

• Morgan Hans,
• Jan Lorkowski,
• Albert Demonceau and
• Lionel Delaude

Beilstein J. Org. Chem. 2015, 11, 2318–2325, doi:10.3762/bjoc.11.252

• just a single example, NHC ligands played a crucial role in the development of highly efficient ruthenium initiators for olefin metathesis and related reactions [18][19][20][21]. Lately, these divalent carbon species have also emerged as powerful nucleophilic organocatalysts for polymer chemistry [22

Ru complexes of Hoveyda–Grubbs type immobilized on lamellar zeolites: activity in olefin metathesis reactions

• Hynek Balcar,
• Naděžda Žilková,
• Martin Kubů,
• Michal Mazur,
• Zdeněk Bastl and
• Jiří Čejka

Beilstein J. Org. Chem. 2015, 11, 2087–2096, doi:10.3762/bjoc.11.225

• cationic tags on NHC ligands were linker-free immobilized on the surface of lamellar zeolitic supports (MCM-22, MCM-56, MCM-36) and on mesoporous molecular sieves SBA-15. The activity of prepared hybrid catalysts was tested in olefin metathesis reactions: the activity in ring-closing metathesis of

• immobilization; olefin metathesis; Introduction Immobilization of Ru alkylidene complexes (Grubbs and Hoveyda–Grubbs type catalysts) on siliceous supports represents a successful way to highly active, selective, and reusable metathesis catalysts [1][2][3][4]. Mesoporous molecular sieves (MCM-41, MCM-48, SBA-15

Olefin metathesis in air

• Lorenzo Piola,
• Fady Nahra and
• Steven P. Nolan

Beilstein J. Org. Chem. 2015, 11, 2038–2056, doi:10.3762/bjoc.11.221

• been made to render catalysts more stable and yet more functional group tolerant. This review summarizes the major developments concerning catalytic systems directed towards water and air tolerance. Keywords: air stability; catalysis; olefin metathesis; RCM; ROMP; ruthenium; Introduction Transition

• , late transition metals, which do not exhibit high oxophilicity, appeared as the most promising candidates for reactions performed in air. Indeed in 1988, Grubbs and Novak reported that not only ruthenium was an interesting candidate for olefin metathesis, but also that reactions were successfully

• solvents, and yielded products with high enantiomeric excess (ee). The results where comparable to previously reported results for molybdenum-catalyzed systems [57], although the latter was used under inert conditions. In 2003, Blechert et al. reported the first systematic example of olefin metathesis in

Hexacoordinate Ru-based olefin metathesis catalysts with pH-responsive N-heterocyclic carbene (NHC) and N-donor ligands for ROMP reactions in non-aqueous, aqueous and emulsion conditions

• Shawna L. Balof,
• K. Owen Nix,
• Matthew S. Olliff,
• Sarah E. Roessler,
• Arpita Saha,
• Kevin B. Müller,
• Ulrich Behrens,
• Edward J. Valente and
• Hans-Jörg Schanz

Beilstein J. Org. Chem. 2015, 11, 1960–1972, doi:10.3762/bjoc.11.212

• the polymerization process. Furthermore, the coagulate content for all experiments stayed <2%. This represents an unprecedented efficiency in emulsion ROMP based on hydrophilic ruthenium alkylidene complexes. Keywords: activation; aqueous catalysis; emulsion; olefin metathesis; polymerization

• ; ruthenium; Introduction The vast application spectrum of Ru-based olefin metathesis has provided a powerful synthetic tool for the organic [1][2][3] and polymer chemist [4][5][6][7][8] alike. The catalysts’ high tolerance towards functional groups, air and moisture makes them attractive to be used in

• combination of a wide range of substrates and solvents [9][10][11][12]. Over the past decade, Ru–alkylidene based olefin metathesis in aqueous media has become increasingly important [13]. Benefits such as the non-hazardous, vastly abundant and commercially highly attractive of water coupled with a high heat

New aryloxybenzylidene ruthenium chelates – synthesis, reactivity and catalytic performance in ROMP

• Patrycja Żak,
• Szymon Rogalski,
• Mariusz Majchrzak,
• Maciej Kubicki and
• Cezary Pietraszuk

Beilstein J. Org. Chem. 2015, 11, 1910–1916, doi:10.3762/bjoc.11.206

• ) and a single selected norbornene derivative. Keywords: chemoactivation; latent catalysts; metathesis; ROMP; ruthenium; Introduction Olefin metathesis is nowadays one of the most important methods for the formation of carbon–carbon bonds in organic and polymer chemistry [1][2]. The availability of

• . Coordination motif of latent catalyst of olefin metathesis in which alkylidene ligand is bound to the heteroatom X, acting as an anionic ligand. Known latent catalysts of olefin metathesis in which alkylidene ligands are bound to a heteroatom, acting as an anionic ligand. Selected, known aryloxybenzylidene

Profluorescent substrates for the screening of olefin metathesis catalysts

• Raphael Reuter and
• Thomas R. Ward

Beilstein J. Org. Chem. 2015, 11, 1886–1892, doi:10.3762/bjoc.11.203

• screening; ring closing metathesis; Introduction Since its discovery in the 1950s, olefin metathesis has developed into one of the most powerful catalytic reactions both in research as well as in industrial applications [1][2][3]. This is mostly due to its excellent chemoselectivity, tolerance of many

• functional groups and its atom economy [4]. Chemists treasure its extraordinary versatility. From the production of polymers [5][6] and petrochemicals to the synthesis of complex natural products [7], olefin metathesis has been established as a useful tool for solving numerous synthetic challenges. In more

• have been prepared and tailored towards specific applications [12]. With the ultimate aim of identifying new olefin metathesis catalysts using high-throughput screening, we set out to develop and evaluate olefinic substrates amenable to a 96-well plate screening format. Results and Discussion A quick

Cross metathesis of unsaturated epoxides for the synthesis of polyfunctional building blocks

• Meriem K. Abderrezak,
• Kristýna Šichová,
• Nancy Dominguez-Boblett,
• Antoine Dupé,
• Zahia Kabouche,
• Christian Bruneau and
• Cédric Fischmeister

Beilstein J. Org. Chem. 2015, 11, 1876–1880, doi:10.3762/bjoc.11.201

• double bond transformations by olefin metathesis have significantly impacted organic and polymer synthesis over the last two decades [1][2][3]. If early works focused on ring-closing metathesis and ring-opening metathesis polymerization, progresses in catalysts performances [4][5] and selectivity have

• necessary to ensure high conversion. Reactions were carried out in dimethyl carbonate (DMC), a solvent compatible with ruthenium olefin metathesis catalysts [28] while being much greener than toluene or dichloromethane commonly used in such reactions [29]. Based on our previous results and observations in