A General Method for Preparation of Metal Carbenes via Solution- and Polymer-Based Approaches

Gandelman, Mark; Naing, Kyaw Myo; Rybtchinski, Boris; Poverenov, Elena; Ben‐David, Yehoshoa; Ashkenazi, Nissan; Gauvin, Régis M.; Milstein, David

doi:10.1021/ja050781+

Cited by 51 publications

(27 citation statements)

References 64 publications

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“…[19] Deprotonation of diphenylmethylsulfonium tetraphenylborate with lithium hexamethyldisilazide at −78 °C gave the methylidene-bearing sulfur ylide, which was added to a solution of 2 in THF (Scheme 2). The 31 P{ 1 H} NMR spectrum collected immediately upon warming exhibited two doublets (δ P = 48.4, 39.0 ppm; J PP = 9 Hz) indicating inequivalent magnetic environments for the phosphines of the ligand coupling weakly to one another, while the 1 H NMR spectrum contained a resonance consistent with insertion of a methylidene into a Ni-P bond to yield a phosphine/phosphine-ylide ligand environment about Ni ( 5 ) [δ H = 0.45 ppm (dd, J = 18.4, 6.8 Hz)].…”

Section: Resultsmentioning

confidence: 99%

Arene CH Amination at Nickel in Terphenyl–Diphosphine Complexes with Labile Metal–Arene Interactions

Herbert

Lara

Agapie

2013

Chemistry A European J

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The meta-terphenyl diphosphine, m-P2: 1, was utilized to support Ni centers in the oxidation states 0, I and II. A series of complexes bearing different substituents and/or ligands at Ni were prepared to investigate the dependence of metal-arene interactions on oxidation state and substitution at the metal. Compound (m-P2)Ni (2), shows close Ni(0)-arene interactions between the metal centre and the central arene ring of the terphenyl ligand both in solution and the solid-state. These interactions are significantly less pronounced in Ni(0) complexes bearing L-type ligands (2-L: L = CH3CN, CO, Ph2CN2), Ni(I)X complexes [3-X: X = Cl, BF4, N3, N3B(C6F5)3] and (m-P2)Ni(II)Cl2 (4). Complex 2 reacts with substrates such as diphenyldiazoalkane, sulfur ylides (Ph2S=CH2), organoazides (RN3: R = para-C6H5OMe, para-C6H5CF3, 1-adamantyl) and N2O with the locus of observed reactivity dependent on the nature of the substrate, leading to isolation of an η1-diphenyldiazoalkane adduct (2-Ph2CN2), methylidene insertion into a Ni-P bond, followed by rearrangement of a nickel-bound phosphorus ylide (5) to a benzylphosphine (6), Staudinger oxidation of the phosphine arms and metal-mediated nitrene insertion into an arene C-H bond of 1 to give the insertion product 8, all derived from the same compound (2). Hydrogen atom abstraction from a nickel(I)-amide (9) and resulting nitrene transfer chemistry supports the viability of nickel-imide intermediates in the reaction of 1 with 1-azido-arenes.

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Section: Resultsmentioning

confidence: 99%

Arene CH Amination at Nickel in Terphenyl–Diphosphine Complexes with Labile Metal–Arene Interactions

Herbert

Lara

Agapie

2013

Chemistry A European J

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“…[44] Sulfur ylides generated in situ from sulfonium salts were also used as carbenoid precursors along these lines. [45] A second strategy takes advantage of the metathetical activity of ruthenium-indenylidene species to convert them into alkylidene derivatives via cross-metathesis with an appropriate alkene introduced in stoichiometric proportion or in excess. Although a further step is required to reach the desired product, this method has several practical assets, owing to the ease of formation and stability of Ru-indenylidene complexes.…”

Section: Preparative Applicationmentioning

confidence: 99%

Homobimetallic Ruthenium Vinylidene, Allenylidene, and Indenylidene Complexes: Synthesis, Characterization, and Catalytic Studies

et al. 2009

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Four homobimetallic ruthenium-(pcymene) complexes bearing a tricyclohexylphosphine ligand and polyunsaturated carbon-rich fragments were obtained via a vinylidene-allenylidene-indenylidene cascade pathway from the ethylene complex. All the products were isolated and fully characterized by IR and NMR spectroscopies. The molecular structure of the indenylidene complex 11 was determined by X-ray crystallographic analysis. The catalytic activity of the four complexes was probed in various types of olefin metathesis reactions and compared with those of a related homobimetallic ruthenium-benzylidene complex, as well as first, second, and third generation monometallic Grubbs catalysts. In the ring-closing metathesis (RCM) of diethyl di-A C H T U N G T R E N N U N G allylmalonate, the homobimetallic ruthenium-indenylidene complex 11 outperformed all the rutheniumbenzylidene complexes under investigation and was only slightly less efficient than its monometallic parent. Cross-metathesis experiments with ethylene showed that deactivation of ruthenium-benzylidene or indenylidene complexes was due to the rapid bimolecular decomposition of methylidene active species into ethylene complex 7a. Vinylidene and allenylidene complexes were far less efficient catalyst precursors for ring-opening metathesis polymerization (ROMP) or RCM and remained inert under an ethylene atmosphere. Their catalytic activity was, however, substantially enhanced upon addition of an acidic co-catalyst that most likely promoted their in situ transformation into indenylidene species. Due to its straightforward synthesis and high metathetical activity, homobimetallic ruthenium-indenylidene complex 11 is a valuable intermediate for the preparation of the Hoveyda-Grubbs catalyst A C H T U N G T R E N N U N G [Cl 2 RuA C H T U N G T R E N N U N G (PCy 3 )(=CH-o-O-i-PrC 6 H 4 )] via stoichiometric cross-metathesis with 2-isopropoxystyrene. The procedure did not require any sacrificial phosphine and the transition metal not incorporated into the final product was easily recovered and recycled at the end of the process.

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“…(394)) [1580]. Reactions of Fischer carbenes bound to a polymer formed by replacement of a carbon monoxide ligand with a polymer bound isonitrile were described [1581].…”

Section: Reactions Of Isolated Transitionmetal Complexes and Copper-mentioning

confidence: 99%

Transition metals in organic synthesis: Highlights for the year 2005

Söderberg

2008

Coordination Chemistry Reviews

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A General Method for Preparation of Metal Carbenes via Solution- and Polymer-Based Approaches

Cited by 51 publications

References 64 publications

Arene CH Amination at Nickel in Terphenyl–Diphosphine Complexes with Labile Metal–Arene Interactions

Arene CH Amination at Nickel in Terphenyl–Diphosphine Complexes with Labile Metal–Arene Interactions

Homobimetallic Ruthenium Vinylidene, Allenylidene, and Indenylidene Complexes: Synthesis, Characterization, and Catalytic Studies

Transition metals in organic synthesis: Highlights for the year 2005

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