Hoveyda–Grubbs catalysts with an N→Ru coordinate bond in a six-membered ring. Synthesis of stable, industrially scalable, highly efficient ruthenium metathesis catalysts and 2-vinylbenzylamine ligands as their precursors

• Kirill B. Polyanskii,
• Kseniia A. Alekseeva,
• Pavel V. Raspertov,
• Pavel A. Kumandin,
• Eugeniya V. Nikitina,
• Atash V. Gurbanov and
• Fedor I. Zubkov

Beilstein J. Org. Chem. 2019, 15, 769–779, doi:10.3762/bjoc.15.73

• the target ruthenium complexes shown in Scheme 4. This transformation was carried out using known standard methods including the interaction of the indenylidene derivative 8 with 1,3-dimesityl-2-(trichloromethyl)imidazolidine (9) [47][48][49][50]. Several approaches have been described earlier for the

• alkali in the last step, which provides the target high-purity imidazolidine in 85–87% yield. We stress that there is no need for the isolation and purification of intermediate substances. The introduction of Ru-indenylidene complex 8 in one-pot reaction with adduct 9 followed by reaction with styrenes

Application of olefin metathesis in the synthesis of functionalized polyhedral oligomeric silsesquioxanes (POSS) and POSS-containing polymeric materials

• Patrycja Żak and
• Cezary Pietraszuk

Beilstein J. Org. Chem. 2019, 15, 310–332, doi:10.3762/bjoc.15.28

• -2-ene as model olefins (Scheme 16). For the majority of the ruthenium catalysts tested, despite the mild reaction conditions, high yields were observed. No reaction or lower yields of the test reaction products were observed for first generation catalysts and indenylidene complexes. For further

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

• activity and selectivity of the corresponding catalysts. Quite recently, on the basis of a previous work, Verpoort et al. reported on the synthesis and characterization of second generation ruthenium indenylidene catalysts bearing N-alkyl, N’-mesityl-substituted NHCs 41–43 in which the alkyl group was

• methyl (41), octyl (42) or cyclohexyl (43, Figure 11) [25]. For all of the complexes, two rotamers were observed in solution, and the most abundant species was identified as the isomer with the indenylidene moiety located under the mesityl group. Solid-state structures of the complexes showed

• , consistently, the same relative orientation between the indenylidene and mesityl unit. Complexes 41–43 were tested in various representative metathesis reactions of standard substrates and compared to the benchmark catalysts IndII-SIMes. Interestingly, all complexes showed a faster catalytic initiation than

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

• generate and/or describe the activity in olefin metathesis of the new indenylidene derivatives. The phenyl substituent of the indenylidene is perpendicular to the indenyl moiety in the solid-state structure [34], as Nolan and co-workers first described in 1999 [35]. For complexes 3–6, where the phenyl ring

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

• different distances from the carbene carbon. We show that the predicted initiation rates of Grubbs, indenylidene, and Hoveyda–Grubbs-like complexes incorporating these carbenes show little variance and are similar to initiation rates of standard Grubbs, indenylidene, and Hoveyda–Grubbs catalysts. In all

• , but also on the properties and initiation rates of the most important ruthenium-based metathesis catalysts, including Grubbs, indenylidene, and Hoveyda–Grubbs complexes, as well as carbene dimerization. We also considered two different solvents: dichloromethane, which is a standard solvent for

• Gibbs free energies all system apart from 1st generation Grubbs and indenylidene-like complexes, for which we used pure M06. Results for all systems and both M06 and M06-D3 methods are listed in Supporting Information File 1. Dimerization The tendency of selected NHC to dimerize is a well-known and

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

• File 1 for further details) in the presence of air. The fastest polymerizations show the indenylidene derivatives bearing dichloroquinolinolate ligand(s) (1a, 1b and 4). Preinitiator 2b is slower in converting 5 but still satisfying conversion is obtained after about 4.5 hours. In contrast

• the following Ru-based complexes belongs to a patent application [63]. Chloro-(κ2-(N,O)-5,7-dichloro-8-quinolinolate)-(3-phenyl-1-indenylidene)-(1,3-bis(2,4,6-trimethylphenyl)-4,5-dihydroimidazol-2-ylidene)ruthenium (1a). Complex 1a was prepared according to the general procedure given above, using

• -32)-Bis(κ2-(N,O)-5,7-dichloro-8-quinolinolate)-(3-phenyl-1-indenylidene)-(1,3-bis(2,4,6-trimethylphenyl)-4,5-dihydroimidazol-2-ylidene)ruthenium (1b). Complex 1b was isolated from the same experiment than 1a using column chromatography. Yield 8.4 mg (20%). Anal. calcd for C54H44Cl4N4O2Ru: C, 63.35; H

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

• the O–Ru bond [59][60][61]. Its use in air was reported by Olszewski, Skowerski and co-workers in a comparison with other catalysts (see section on indenylidene complexes, below) [62]. Soon after, in 2006, the same group presented a variation of the Hoveyda–Grubbs 2nd generation catalyst, bearing a

• the use of 81 in the living ROMP of a hydrophilic norbornene monomer in air, leading to the formation of hydrogels [71]. Despite the living character of this reaction, the propagating catalyst was found to be inactive after 1 hour. Indenylidene complexes The indenylidene-bearing family of complexes

• increased activity and maintained the same thermal stability. Again, these complexes showed similar activity to the Grubbs 2nd generation catalysts [77][78], and are stable when stored under air. Nolan reported the synthesis of Grubbs’ 2nd generation catalyst (15) from indenylidene complexes 84, by simple

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

• Grubbs-type catalysts with either a benzylidene ligand or an indenylidene ligand. As a model reaction, we selected ring-closing metathesis and developed two profluorescent substrates that yield a fluorescent product upon ring-closing metathesis (Scheme 1). Substrate 5 consists of a fluorescent 5

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

• the first Z-selective catalysts [18][19][20][21]. Their efficiency, however, is noticeably lower than that observed for classical complexes. The second generation indenylidene catalysts with phosphite ligand (frequently reported as “Cazin-type catalysts”) bearing mixed chloride–fluoride or difluoride

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

• Cedex, France 10.3762/bjoc.11.169 Abstract A silver-free methodology was developed for the synthesis of unprecedented N-heterocyclic carbene ruthenium indenylidene complexes bearing a bidentate picolinate ligand. The highly stable (SIPr)(picolinate)RuCl(indenylidene) complex 4a (SIPr = 1,3-bis(2-6

• . 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

• ][19]. Nevertheless, indenylidene complexes, that have notably showed an improved stability in comparison to their benzylidene counterparts [20][21][22], have never been considered in association with picolinic ligands for the synthesis of robust latent catalysts. Moreover, this strategy would provide

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

• Stefano Guidone Fady Nahra Alexandra M. Z. Slawin Catherine S. J. Cazin EaStCHEM School of Chemistry, University of St Andrews, St Andrews, UK, KY16 9ST, UK 10.3762/bjoc.11.166 Abstract The reaction of triisopropyl phosphite with phosphine-based indenylidene pre-catalysts affords “1st generation

• -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

• halides. The apex of the pyramid is occupied by an alkylidene moiety, such as a benzylidene or an indenylidene. Mixed NHC/phosphine complexes (G-II and Ind-II) known as “2nd generation” pre-catalysts generally display higher catalytic activity than “1st generation” complexes (G-I and Ind-I) containing two

The cross-metathesis of methyl oleate with cis-2-butene-1,4-diyl diacetate and the influence of protecting groups

• Arno Behr and
• Jessica Pérez Gomes

Beilstein J. Org. Chem. 2011, 7, 1–8, doi:10.3762/bjoc.7.1

• observed between the benzylidene catalyst [Ru]-1 and its indenylidene counterpart [Ru]-3. The self-metathesis of methyl oleate (1) mentioned above could not be suppressed. Other side-reactions were not observed. No double-bound isomerisation took place. Promising results were obtained with catalysts

• and an inexpensive base chemical was prepared. Various metathesis catalysts were investigated, disclosing that the Schiff base ruthenium indenylidene catalyst [Ru]-7 bearing a N-heterocyclic carbene ligand, which is an already industrial implemented metathesis catalyst, led to high conversions and

• content (91.4% oleic acid) was obtained from Emery Oleochemicals. cis-2-Butene-1,4-diol (8) (97%), solvents and reagents were purchased from Sigma-Aldrich. Benzylidene ruthenium catalysts [Ru]-1 and [Ru]-2 were obtained from Sigma-Aldrich and the remaining indenylidene ruthenium catalysts [Ru]-3–[Ru]-8

The catalytic performance of Ru–NHC alkylidene complexes: PCy₃ versus pyridine as the dissociating ligand

• Stefan Krehl,
• Diana Geißler,
• Sylvia Hauke,
• Oliver Kunz,
• Lucia Staude and
• Bernd Schmidt

Beilstein J. Org. Chem. 2010, 6, 1188–1198, doi:10.3762/bjoc.6.136

• Stefan Krehl Diana Geissler Sylvia Hauke Oliver Kunz Lucia Staude Bernd Schmidt Universität Potsdam, Institut für Chemie, Organische Synthesechemie, Karl-Liebknecht-Straße 24–25, D-14476 Golm, Germany 10.3762/bjoc.6.136 Abstract The catalytic performance of NHC-ligated Ru-indenylidene or

• propargylic alcohols as alkylidene precursors [10], which resulted in the synthesis of a first generation analogue C with an indenylidene ligand [11][12]. A landmark in the evolution of Ru-metathesis catalysts was the introduction of alkylidene complexes bearing N-heterocyclic carbenes (NHC) [13][14][15], in

• might be a particularly useful property for metathesis polymerization reactions [37]. More recently, Ru-indenylidene complexes bearing one or two pyridine ligands were also synthesized [38][39], with the commercially available Umicore M31 catalyst H being a particularly interesting example. This

Tandem catalysis of ring-closing metathesis/atom transfer radical reactions with homobimetallic ruthenium–arene complexes

• Yannick Borguet,
• Xavier Sauvage,
• Guillermo Zaragoza,
• Albert Demonceau and
• Lionel Delaude

Beilstein J. Org. Chem. 2010, 6, 1167–1173, doi:10.3762/bjoc.6.133

• Compostela, Campus Vida, 15782 Santiago de Compostela, Spain 10.3762/bjoc.6.133 Abstract The tandem catalysis of ring-closing metathesis/atom transfer radical reactions was investigated with the homobimetallic ruthenium–indenylidene complex [(p-cymene)Ru(μ-Cl)3RuCl(3-phenyl-1-indenylidene)(PCy3)] (1) to

• the Ru(II)–Ru(III) mixed-valence compound [(p-cymene)Ru(μ-Cl)3RuCl2(PCy3)], which was found to be an efficient promoter for atom transfer radical reactions under the adopted experimental conditions. Keywords: Grubbs catalyst; indenylidene ligands; Kharasch reaction; microwave heating; olefin

• metathesis; Introduction During the course of our investigations on homobimetallic ruthenium–arene complexes, we found that the indenylidene compound [(p-cymene)Ru(μ-Cl)3RuCl(3-phenyl-1-indenylidene)(PCy3)] (1) was a very efficient promoter for the ring-closing metathesis (RCM) of diethyl 2,2

New library of aminosulfonyl-tagged Hoveyda–Grubbs type complexes: Synthesis, kinetic studies and activity in olefin metathesis transformations

• Etienne Borré,
• Frederic Caijo,
• Christophe Crévisy and
• Marc Mauduit

Beilstein J. Org. Chem. 2010, 6, 1159–1166, doi:10.3762/bjoc.6.132

• ). Ligands 6a–f were isolated in moderate to good yields (60–80%). Their reaction with Ru-indenylidene complex 7a [21] or 7b [22] in the presence of CuCl afforded the expected precatalysts 4a–g in good yields. Then, the reactivity profile of each catalyst was investigated using 1H NMR monitored kinetic

• , CDCl3, δ): −63.1. General procedure for catalyst formation: To a solution of catalyst 7 and copper chloride (1.1 equiv) in dry DCM (1 mL for 0.02 mmol of Ru-indenylidene complex) was added a solution of 6a–f (1 equiv) in DCM (1 mL for 0.05 mmol of ligand). The resulting mixture was stirred at 35 °C for

About the activity and selectivity of less well-known metathesis catalysts during ADMET polymerizations

• Hatice Mutlu,
• Lucas Montero de Espinosa,
• Oĝuz Türünç and
• Michael A. R. Meier

Beilstein J. Org. Chem. 2010, 6, 1149–1158, doi:10.3762/bjoc.6.131

• , Department of Colloid Chemistry, Potsdam, Germany 10.3762/bjoc.6.131 Abstract We report on the catalytic activity of commercially available Ru-indenylidene and “boomerang” complexes C1, C2 and C3 in acyclic diene metathesis (ADMET) polymerization of a fully renewable α,ω-diene. A high activity of these

• ; metathesis; olefin isomerization; renewable raw materials; ruthenium–indenylidene catalysts; Introduction Among the large number of organic and organometallic reactions allowing the formation of carbon–carbon bonds, olefin metathesis has found its place in organic synthesis as well as polymer science as a

• initiators available, we focused this study on the application of the less investigated indenylidene Ru-based catalysts: (1,3-bis(2,4,6-trimethylphenyl)-2-imidazolidinylidene) dichloro-(3-phenyl-1H-inden-1-ylidene)(tricyclohexylphosphine) ruthenium(II) (C1), (1,3-bis(2,4,6-trimethylphenyl)-2

Backbone tuning in indenylidene–ruthenium complexes bearing an unsaturated N-heterocyclic carbene

• César A. Urbina-Blanco,
• Xavier Bantreil,
• Hervé Clavier,
• Alexandra M. Z. Slawin and
• Steven P. Nolan

Beilstein J. Org. Chem. 2010, 6, 1120–1126, doi:10.3762/bjoc.6.128

• electronic parameter (electronic) and the percent buried volume (%Vbur, steric) parameters. The corresponding ruthenium–indenylidene complexes were also synthesized and tested in benchmark metathesis transformations to establish possible correlations between reactivity and NHC electronic and steric

• parameters. Keywords: N-heterocyclic carbene; olefin metathesis; percent buried volume; ruthenium–indenylidene; Tolman electronic parameter; Introduction The use of N-heterocyclic carbenes (NHC) as spectator ligands in ruthenium-mediated olefin metathesis represents one of the most important breakthroughs

• via an observed C–H activation route [19]. These results encouraged us to explore the electronic influence of backbone substitution in unsaturated NHCs with ruthenium–indenylidene complexes. Indenylidene catalysts are rapidly becoming quite popular [20][21], due to the availability of ruthenium

Halide exchanged Hoveyda-type complexes in olefin metathesis

• Julia Wappel,
• César A. Urbina-Blanco,
• Mudassar Abbas,
• Jörg H. Albering,
• Robert Saf,
• Steven P. Nolan and
• Christian Slugovc

Beilstein J. Org. Chem. 2010, 6, 1091–1098, doi:10.3762/bjoc.6.125

• (Scheme 1). M2 is a relatively more economic alternative to G2, bearing an indenylidene instead of a benzylidene ligand [22][23][24]. Adopting Hoveyda’s protocol for obtaining 1 from G2 [25] and using 1-isopropoxy-2-(prop-1-en-1-yl)benzene as the carbene precursor, 1 can be obtained in 78% yield