Recent applications of ring-rearrangement metathesis in organic synthesis

• Sambasivarao Kotha,
• Milind Meshram,
• Priti Khedkar,
• Shaibal Banerjee and
• Deepak Deodhar

Beilstein J. Org. Chem. 2015, 11, 1833–1864, doi:10.3762/bjoc.11.199

• have covered literature that appeared during the last seven years (2008–2014). Keywords: Diels–Alder chemistry; green chemistry; natural products; olefin metathesis; polycycles; ring-rearrangement metathesis; Introduction Transition metal–carbene complexes (Figure 1) introduced during the last two

• decades have changed the landscape of organic synthesis. Armed with these advances, olefin metathesis has become a staple in retrosynthesis. Metathesis protocols such as ring-closing metathesis (RCM), cross-metathesis (CM), and enyne metathesis (EM) have gained popularity in the synthesis of complex

Nitro-Grela-type complexes containing iodides – robust and selective catalysts for olefin metathesis under challenging conditions

• Andrzej Tracz,
• Mateusz Matczak,
• Katarzyna Urbaniak and
• Krzysztof Skowerski

Beilstein J. Org. Chem. 2015, 11, 1823–1832, doi:10.3762/bjoc.11.198

• ; ruthenium; Introduction Olefin metathesis (OM) is a mild and versatile catalytic method which allows the formation of carbon–carbon double bonds [1]. Understanding the key events in ruthenium-catalyzed olefin metathesis [2] and developing efficient and selective catalysts [3] provides opportunities for

• with fair yields (77% and 57% of 19 and 20, respectively) while other catalysts demonstrated less than a 10% yield. Metathesis in ACS-grade and “green” solvents Our continuous interest in the development of more sustainable, environmentally and user-friendly olefin metathesis has recently inspired us

Cross-metathesis of polynorbornene with polyoctenamer: a kinetic study

• Yulia I. Denisova,
• Maria L. Gringolts,
• Alexander S. Peregudov,
• Liya B. Krentsel,
• Ekaterina A. Litmanovich,
• Arkadiy D. Litmanovich,
• Eugene Sh. Finkelshtein and
• Yaroslav V. Kudryavtsev

Beilstein J. Org. Chem. 2015, 11, 1796–1808, doi:10.3762/bjoc.11.195

• unit reshuffling in unsaturated carbon-chain polymers, such as polydienes, which constitute a core of commercially available elastomers. As soon as the olefin metathesis was discovered, it became possible to think on the implementation of cross-reactions between C=C bonds in polymers. Until recently

• accepted mechanism of olefin metathesis mediated by Gr-1 [30], this signal can be attributed to a new, secondary carbene ([Ru]=PCOE) formed via break up of a PCOE chain attacked by a primary carbene, as shown in Scheme 1. The mixture viscosity was considerably reduced at the early stage of the reaction (10

A comprehensive study of olefin metathesis catalyzed by Ru-based catalysts

• Albert Poater and
• Luigi Cavallo

Beilstein J. Org. Chem. 2015, 11, 1767–1780, doi:10.3762/bjoc.11.192

• species is also discussed, with either pyridine or phosphine ligands to dissociate. Keywords: cis; density functional theory (DFT); N-heterocyclic carbene; olefin metathesis; ruthenium; Introduction Organic synthesis is based on reactions that drive the formation of carbon–carbon bonds [1]. Olefin

• metathesis represents a metal-catalyzed redistribution of carbon–carbon double bonds [2][3][4][5][6] and provides a route to unsaturated molecules that are often challenging or impossible to prepare by any other means. Furthermore, the area of ruthenium-catalyzed olefin metathesis reactions is an outstanding

• halogen group to a trans position (side path in Scheme 2). Bearing the general acceptance [39][40][41][42][43][44][45] that olefin metathesis with Ru-catalysts starts from a bottom-bound olefin complex because of energetics, i.e., reporting higher energies for the possible side-bound olefin complexes

Progress in metathesis chemistry II

• Karol Grela

Beilstein J. Org. Chem. 2015, 11, 1639–1640, doi:10.3762/bjoc.11.179

• Karol Grela Biological and Chemical Research Centre, Faculty of Chemistry, University of Warsaw, Żwirki i Wigury 101, 02-089 Warsaw, Poland Institute of Organic Chemistry, Polish Academy of Sciences, Kasprzaka 44/52, 01-224 Warsaw, Poland 10.3762/bjoc.11.179 Keywords: olefin metathesis;   Joseph

• Conrad – The Shadow-Line Five years have passed since the first publication of the Thematic Series on Olefin Metathesis in the Beilstein Journal of Organic Chemistry [1]. During these years the research continued to progress at full speed. Astute readers of this Thematic Series, as well as readers of the

• recent books devoted to olefin metathesis [2][3], can easily see that a great number of studies in this field have advanced from the basic research phase to the commercial application stage. While new, active and more selective catalysts that solve some longstanding limitations are still being developed

Grubbs–Hoveyda type catalysts bearing a dicationic N-heterocyclic carbene for biphasic olefin metathesis reactions in ionic liquids

• Maximilian Koy,
• Hagen J. Altmann,
• Benjamin Autenrieth,
• Wolfgang Frey and
• Michael R. Buchmeiser

Beilstein J. Org. Chem. 2015, 11, 1632–1638, doi:10.3762/bjoc.11.178

• NHC ligands. Attempts to synthesize ionic Ru-based olefin metathesis catalysts using imidazolinium salts bearing two quaternary ammonium groups turned out to be unsuccessful, probably due to their insolubility in common organic solvents. However, quaternization of RuCl2(H2ITap)(=CH–(2-(2-PrO-C6H4

• organic phase (see Supporting Information File 1). It is thus also in line with the fact that Ru–alkylidenes based on electron-rich NHCs, e.g., based on tetrahydropyrimidin-2-ylidenes [23], strongly promote olefin metathesis. Biphasic ring-opening metathesis polymerization (ROMP) reactions To test the

Latent ruthenium–indenylidene catalysts bearing a N-heterocyclic carbene and a bidentate picolinate ligand

• Thibault E. Schmid,
• Florian Modicom,
• Adrien Dumas,
• Etienne Borré,
• Loic Toupet,
• Olivier Baslé and
• Marc Mauduit

Beilstein J. Org. Chem. 2015, 11, 1541–1546, doi:10.3762/bjoc.11.169

• . Keywords: latent catalyst; olefin metathesis; picolinate ligand; ruthenium indenylidene; Introduction Olefin metathesis has witnessed tremendous development in the last decades and has emerged as a powerful tool with dramatic impact on both organic chemistry and materials science [1][2]. Intensive

• metathesis profiles in response to TFA equivalents. Comparison of olefin metathesis profiles for catalysts 2, 4a and 4b after activation with 150 equiv of TFA. Influence of various acids for the activation of 4a in the RCM of DEDAM. Synthesis of [NHC(picolinate)RuCl(indenylidene)] complexes 2 and 4a

• % isolated yields, respectively. Finally, the cross metathesis reaction between allylbenzene and ethyl acrylate afforded the desired internal E-olefin with 62% yield. Conclusion We described the synthesis and characterization of three novel latent 2nd generation indenylidene-based precatalysts for olefin

Ruthenium indenylidene “1^st generation” olefin metathesis catalysts containing triisopropyl phosphite

• Stefano Guidone,
• Fady Nahra,
• Alexandra M. Z. Slawin and
• Catherine S. J. Cazin

Beilstein J. Org. Chem. 2015, 11, 1520–1527, doi:10.3762/bjoc.11.166

• ” cis-complexes. These have been used in olefin metathesis reactions. The cis-Ru species exhibit noticeable differences with the trans-Ru parent complexes in terms of structure, thermal stability and reactivity. Experimental data underline the importance of synergistic effects between phosphites and L

• -type ligands. Keywords: 1st generation; indenylidene; metathesis; phosphite; ruthenium; Introduction The olefin metathesis reaction is a powerful tool for C–C bond formation in the synthesis of highly valuable organic compounds [1][2][3][4]. Protocols involving W-, Mo- and Ru-based pre-catalysts can

• geometries with the P-donor ligands mutually cis as the most thermodynamically stable conformation. The isolation of the corresponding trans-isomers was not possible due to a fast isomerization process occurring during the synthesis of the complexes. Pre-catalyst 1 was found to be active in olefin metathesis

Design and synthesis of hybrid cyclophanes containing thiophene and indole units via Grignard reaction, Fischer indolization and ring-closing metathesis as key steps

• Sambasivarao Kotha,
• Ajay Kumar Chinnam and
• Mukesh E. Shirbhate

Beilstein J. Org. Chem. 2015, 11, 1514–1519, doi:10.3762/bjoc.11.165

• via Grignard addition, Fischer indolization and ring-closing metathesis as key steps. Keywords: cyclophane; Grignard reaction; Fischer indolization; ring-closing metathesis; Introduction Modern olefin metathesis catalysts enable a late stage ring-closing step starting with bisolefinic substrates

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

• : glass-transition temperature; polydicyclopentadiene; ring opening metathesis polymerization; ruthenium-catalyzed olefin metathesis; thermoset polymers; Introduction Olefin metathesis [1][2][3][4][5][6] has advanced to become a major synthetic tool in academia [7][8][9][10][11] and industry [12

• ) (Figure 1). The Grubbs-type ruthenium initiators, known for their high activity, stability and functional group tolerance are extensively used to promote this type of olefin metathesis reactions. For example, the Grubbs second generation catalyst 2 [18] (Figure 1), may be used to initiate ROMP reactions

• the exothermic peak was suppressed while the control experiment (with diethyl ether) behaved as indicated in previous experiments (Figure 7). These results support the theory that an olefin metathesis reaction is occurring and that it is the source of the observed exothermic peak. Conclusion In

Consequences of the electronic tuning of latent ruthenium-based olefin metathesis catalysts on their reactivity

• Karolina Żukowska,
• Eva Pump,
• Aleksandra E. Pazio,
• Krzysztof Woźniak,
• Luigi Cavallo and
• Christian Slugovc

Beilstein J. Org. Chem. 2015, 11, 1458–1468, doi:10.3762/bjoc.11.158

• Arabia 10.3762/bjoc.11.158 Abstract Two ruthenium olefin metathesis initiators featuring electronically modified quinoline-based chelating carbene ligands are introduced. Their reactivity in RCM and ROMP reactions was tested and the results were compared to those obtained with the parent unsubstituted

• reactivity of the complexes. Keywords: DFT calculations; olefin metathesis; ring closing metathesis; ring-opening metathesis polymerisation; ruthenium; Introduction Olefin metathesis is a catalytic process during which C–C double bonds are exchanged [1]. Since the first examples were published in the 1950s

• basic structure of ruthenium-based olefin metathesis catalysts led to a diversification of catalytic profiles (Figure 1) [5][6]. Perhaps the most important one was the introduction of bidentate benzylidene ligands instead of simple alkylidenes, thus giving rise to the class of Hoveyda-type complexes

Design and synthesis of polycyclic sulfones via Diels–Alder reaction and ring-rearrangement metathesis as key steps

• Sambasivarao Kotha and
• Rama Gunta

Beilstein J. Org. Chem. 2015, 11, 1373–1378, doi:10.3762/bjoc.11.148

• RRM protocol. It is clear that RRM has a unique place in olefin metathesis [38][39][40][41][42][43][44][45] and further interesting examples are expected in future. Retrosynthetic approach to polycyclic sulfones. Preparation of the sulfone 6 via oxidation. Synthesis of alkenylated sulfone derivatives

Selected synthetic strategies to cyclophanes

• Sambasivarao Kotha,
• Mukesh E. Shirbhate and
• Gopalkrushna T. Waghule

Beilstein J. Org. Chem. 2015, 11, 1274–1331, doi:10.3762/bjoc.11.142

• -binding abilities, an improved affinity can be achieved by polytopic hosts [61][62][63] through multivalency effects in macrocycles. Olefin metathesis has played a key role in the development of cyclophane chemistry. Some of the catalysts used for this purpose are listed in Figure 3. The development of

• . Subsequently, an olefin metathesis with G-II (13) as a catalyst delivered dimeric 197 and monomeric 198 cyclophane derivatives. Later, the hydrogenation of 197 and 198 gave the corresponding saturated [3.4]cyclophane derivatives 199 and 200, respectively (Scheme 32). Müllen and co-workers [155] have

• with the pentafluorobenzyl ester auxiliary, ester 210 was synthesized in a multistep process and then subjected to olefin metathesis to deliver the macrocycle using the Blechert catalyst 17. The treatment of the pentafluorophenyl benzyl ester 210 with catalyst 17 in toluene afforded the rigid

Amino acid motifs in natural products: synthesis of O-acylated derivatives of (2S,3S)-3-hydroxyleucine

• Oliver Ries,
• Martin Büschleb,
• Markus Granitzka,
• Dietmar Stalke and
• Christian Ducho

Beilstein J. Org. Chem. 2014, 10, 1135–1142, doi:10.3762/bjoc.10.113

• -methylheptanoic acid (26). Synthesis of Fmoc-protected building blocks 38 and 41 suitable for SPPS, with late-stage side chain diversification by olefin metathesis. Optimization of the reaction of 7 to dimethyloxazolidine 8. Supporting Information The Supporting Information features the preparation, analytical

The Flögel-three-component reaction with dicarboxylic acids – an approach to bis(β-alkoxy-β-ketoenamides) for the synthesis of complex pyridine and pyrimidine derivatives

• Mrinal K. Bera,
• Moisés Domínguez,
• Paul Hommes and
• Hans-Ulrich Reissig

Beilstein J. Org. Chem. 2014, 10, 394–404, doi:10.3762/bjoc.10.37

• . Keywords: alkoxyallenes; condensations; DFT calculations; β-ketoenamides; multi-component reactions; olefin metathesis; pyridines; pyrimidines; Introduction Multicomponent reactions (MCRs) generally allow a diversity-oriented fast and efficient access to complex synthetic intermediates and are thus

Novel supramolecular affinity materials based on (−)-isosteviol as molecular templates

• Christina Lohoelter,
• Malte Brutschy,
• Daniel Lubczyk and
• Siegfried R. Waldvogel

Beilstein J. Org. Chem. 2013, 9, 2821–2833, doi:10.3762/bjoc.9.317

• corresponding triptycene derivative all-syn-17 (Scheme 7). Alkylation proceeded with a moderate yield of 31%. Equipped with three terminal alkenes all-syn-17 seems to be a suitable precursor for subsequent olefin metathesis to form a capsule-like structure. The structure of all-syn-17 was confirmed via X-ray

• combination of entire isomer separation and shortcut in the reaction sequence (three steps instead of five, starting from (−)-isosteviol) makes this a highly attractive route for the construction of the desired triptycene derivatives. All-syn-17 was then brought to reaction in an olefin metathesis (Scheme 10

• triptycene 17 by condensation of 18 with hexaammoniumtriptycene hexachloride 4. Olefin metathesis of all-syn-17. Oxidation and esterification sequence of 1. Supporting Information Supporting Information File 500: Characterization data, spectra of synthesized compounds, QCM set up, and QCM screening details

One-pot cross-enyne metathesis (CEYM)–Diels–Alder reaction of gem-difluoropropargylic alkynes

• Santos Fustero,
• Paula Bello,
• Javier Miró,
• María Sánchez-Roselló,
• Günter Haufe and
• Carlos del Pozo

Beilstein J. Org. Chem. 2013, 9, 2688–2695, doi:10.3762/bjoc.9.305

• group, which involved the use of 1,7-octadiene as an internal source of ethylene. Keywords: cross metathesis; Diels–Alder; one-pot reaction; organo-fluorine; propargylic difluorides; Introduction In recent years the number of applications of olefin metathesis as a mild and competitive synthetic method

Bidirectional cross metathesis and ring-closing metathesis/ring opening of a C₂-symmetric building block: a strategy for the synthesis of decanolide natural products

• Bernd Schmidt and
• Oliver Kunz

Beilstein J. Org. Chem. 2013, 9, 2544–2555, doi:10.3762/bjoc.9.289

• -membered ring lactones stagonolide E and curvulide A were synthesized using a bidirectional olefin-metathesis functionalization of the terminal double bonds. Key steps are (i) a site-selective cross metathesis, (ii) a highly diastereoselective extended tethered RCM to furnish a (Z,E)-configured dienyl

• ][4][5][6] and its enantiomer ent-1 [7] have emerged as highly valuable starting points for target molecule syntheses which rely on dual olefin metathesis reactions. The two metathesis transformations may either be two identical CM [8][9] or RCM steps [10], yielding C2-symmetric products in which the

The chemistry of isoindole natural products

• Klaus Speck and
• Thomas Magauer

Beilstein J. Org. Chem. 2013, 9, 2048–2078, doi:10.3762/bjoc.9.243

• prenyl side chain and introduction of the formyl group was accomplished within five steps to give 191a (Scheme 25). The envisioned deprotection of 191a using Lewis acidic conditions led to an unexpected and unprecedented metal-free carbonyl–olefin metathesis. Coordination of boron trifluoride etherate to

End-labeled amino terminated monotelechelic glycopolymers generated by ROMP and Cu(I)-catalyzed azide–alkyne cycloaddition

• Ronald Okoth and
• Amit Basu

Beilstein J. Org. Chem. 2013, 9, 608–612, doi:10.3762/bjoc.9.66

• accomplished by amidation with an azido-amine linker followed by Cu(I)-catalyzed azide–alkyne cycloaddition with propargyl sugars. Subsequent Teoc deprotection and conjugation with pyrenyl isothiocyanates afforded well-defined end-labeled glycopolymers. Keywords: capping agent; carbohydrate; glycan; olefin

• metathesis; triazole; Findings Polymers functionalized with carbohydrate side chains, also referred to as glycopolymers, constitute important synthetic probes for the study of carbohydrate recognition [1][2][3]. Glycopolymers prepared by ring-opening metathesis polymerization (ROMP) of norbornene and

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

• FLPs [35], Mδ+═Eδ− FLPs may also react with nonpolar unsaturated substrates, such as alkenes or alkynes, by polarizing the substrate to facilitate cycloaddition. [2 + 2] cycloadditions of Mδ+═Eδ− FLPs with alkenes/alkynes have been thoroughly explored in the context of olefin metathesis (where E = CR2

Metathesis access to monocyclic iminocyclitol-based therapeutic agents

• Ileana Dragutan,
• Valerian Dragutan,
• Carmen Mitan,
• Hermanus C.M. Vosloo,
• Lionel Delaude and
• Albert Demonceau

Beilstein J. Org. Chem. 2011, 7, 699–716, doi:10.3762/bjoc.7.81

• for the role of olefin metathesis reactions (RCM, CM) as key transformations in the multistep syntheses of pyrrolidine-, piperidine- and azepane-based iminocyclitols, as important therapeutic agents against a range of common diseases and as tools for studying metabolic disorders. Considerable

• ; iminocyclitols; natural products; olefin metathesis; Ru-alkylidene catalysts; Review Introduction Synthetic and natural polyhydroxylated N-heterocyclic compounds (pyrrolidines, piperidines, piperazines, indolizines, etc., and higher homologues), commonly referred to as azasugars, iminosugars or iminocyclitols

• addition, the reaction conditions (temperature, solvents) currently employed in olefin metathesis reactions can be productively transferred to the metathesis steps of iminocyclitols synthesis. By surveying the field of recent azasugar developments, this review focuses on metathesis reactions (mainly RCM

Ene–yne cross-metathesis with ruthenium carbene catalysts

• Cédric Fischmeister and
• Christian Bruneau

Beilstein J. Org. Chem. 2011, 7, 156–166, doi:10.3762/bjoc.7.22

• (Scheme 13) [68]. This is surprising as enol ethers are known to be moderately reactive in olefin metathesis [69] and ethyl vinyl ether is often used to stop ring opening metathesis polymerizations. Vinyl acetate is also a good partner for EYCM under similar conditions. In the presence of 10 mol % of

• [3] demonstrated that alkyne polymerization could be initiated directly from terminal alkynes without previous preparation of a metal carbene but via the formation of a reactive vinylidene tungsten species. Later on, the efficiency of ruthenium vinylidene precursors was also shown in olefin

• metathesis [4][5][6][7][8][9][10]. It is noteworthy that polymerization of terminal alkynes [11][12][13] and cyclotrimerization of triynes [14][15][16][17][18][19][20] with ruthenium carbene precursors is still a topic of current interest. Then, Fischer tungsten carbene complexes were used by Katz [21], and

Olefin metathesis in nano-sized systems

• Didier Astruc,
• Abdou K. Diallo,
• Sylvain Gatard,
• Liyuan Liang,
• Cátia Ornelas,
• Victor Martinez,
• Denise Méry and
• Jaime Ruiz

Beilstein J. Org. Chem. 2011, 7, 94–103, doi:10.3762/bjoc.7.13

• olefin metathesis and dendrimers and other nano systems is addressed in this mini review mostly based on the authors’ own contributions over the last decade. Two subjects are presented and discussed: (i) The catalysis of olefin metathesis by dendritic nano-catalysts via either covalent attachment (ROMP

• ; metathesis; nano-system; water; Introduction Olefin metathesis reactions [1][2][3][4][5][6][7] have been successfully catalyzed under standard conditions, including reactions at room temperature and sometimes even in air, with commercial Grubbs-type catalysts [8][9]. These are now largely developed for

• industry with functional substrates for the synthesis of highly sophisticated pharmaceutical products and polymers. There is continuing research in the olefin metathesis field, however, because of the economical and ecological constraints of modern society. This requires that the catalyst amounts be as low

Recent advances in the development of alkyne metathesis catalysts

• Xian Wu and
• Matthias Tamm

Beilstein J. Org. Chem. 2011, 7, 82–93, doi:10.3762/bjoc.7.12

• metathesis polymerization (ROAMP) and acyclic diyne metathesis polymerization (ADIMET) are known (Scheme 2). In contrast to olefin metathesis, the number of catalysts for alkyne metathesis is far more limited. The first catalyst for alkyne metathesis was a heterogeneous system based on WO3/silica, which was

• imido ligands, which are present in some of the most active olefin metathesis catalysts, i. e., Schrock–Hoveyda-type tungsten and molybdenum imido-alkylidene complexes [10]. We presumed that substitution of the imido ligands by imidazolin-2-iminato ligands and concurrent conversion of the metal–carbon

• hexafluoro-tert-butoxide, OCCH3(CF3)2, proved to be essential for creating active catalysts [74], indicating that successful catalyst design in this system relies on establishing a push-pull situation in a similar fashion present in Schrock–Hoveyda olefin metathesis catalysts (Scheme 4) [10] and also in an