Ring metallation of thiophenechromium tricarbonyl with butyllithium

Nefedova, M. N.; Setkina, V. N.; Kursanov, D.N.

doi:10.1016/s0022-328x(00)98603-0

Cited by 22 publications

(9 citation statements)

References 2 publications

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“…3.47 (t), 3.49 (q), 2.02-1.93 (m), 1.78-1.69 (m), 1.21 (t) 3.47 (q), 3.46 (t), 2.00-1.91 (m), 1.87-1.72 (m), 1.20 (t) 3.51 (t), 3.48 (q), 2.11 (q), 1.83 (q), 1.20 (t) 3.51 (t), 3.47 (q), 2.09 (q), 1.84 (q), 1.20 (t) 1.68 (t) 1.71 (t) ring has been greatly reduced and the signal appears as a slightly broadened quartet. The Cr(CO) 3 , Cr(CO) 5 and W(CO) 5 chemical shifts in the 13 C NMR spectra are insensitive to changes in substituents and compare well with those reported. 22 As is the case for the 1 H NMR chemical shifts, the 13 C shifts of the thienyl carbons are downfield (ca.…”

Section: Spectroscopic Properties Of Complexessupporting

confidence: 84%

See 1 more Smart Citation

Synthesis and structure of bimetallic complexes with σ,π-bridged monocarbene ligands

Terblans¹,

Lotz²

1997

J. Chem. Soc., Dalton Trans.

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Section: Spectroscopic Properties Of Complexessupporting

confidence: 84%

“…12 Metallation of [Cr(SC 4 H 4 )(CO) 3 ] at low temperatures is readily achieved. 13 Another π-bonded heterocycle which could be utilized with ] (M = Cr 5 or W 6). The preparative yields of 3 and 4 were optimized by extending the reaction time at room temperature, but this unfortunately also leads to higher yields of 5 and 6, respectively.…”

Section: Synthesismentioning

confidence: 99%

Synthesis and structure of bimetallic complexes with σ,π-bridged monocarbene ligands

Terblans¹,

Lotz²

1997

J. Chem. Soc., Dalton Trans.

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“…Deprotonation of thiophene in the 2 position is easily achieved in tetrahydrofuran (thf), 19 but because of the reactivity of the organolithium reagent low temperatures are essential. Higher temperatures are required for the formation of dinuclear complexes via salt-elimination reactions.…”

Section: Resultsmentioning

confidence: 99%

Synthesis and structure of bimetallic complexes with σ,π-bridging thienyl and benzothienyl ligands

Toit¹,

Landman²,

Lotz³

1997

J. Chem. Soc., Dalton Trans.

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The ligand properties of the organometallic fragment (η 5 -SC 4 H 3 )Cr(CO) 3 were studied in the new σ,π-bimetallic complexes [Cr{(η 5 -SC 4 H 3 )PtL 2 (SC 4 H 3 )}(CO) 3 ] with L = CO and PMe 3 1 or L 2 = dppe [1,2-bis(diphenylphosphino)ethane] 2, [Cr{(η 5 -SC 4 H 3 )Au(PPh 3 )}(CO) 3 ] 3 and [Cr(η 5 -SC 4 H 3 SnMe 3 )(CO) 3 ] 4. Whereas the intermediates [Cr{(η 5 -SC 4 H 3 )PtL 2 Cl}(CO) 3 ] (L = PMe 3 or dppe) and [Pt{(SC 4 H 3 )Cr(CO) 3 } 2 L 2 ] were too unstable to isolate and characterize, 4 slowly converted into [Cr{η 5 -SC 4 H 2 (SnMe 3 ) 2 }(CO) 3 ] 5. By contrast, the reaction of lithiated [Cr(η 6 -SC 8 H 6 )(CO) 3 ] with [Pt(dppe)Cl 2 ] afforded the stable trinuclear complex, [Pt{(η 6 -SC 8 H 5 )Cr(CO) 3 } 2 (dppe)] 6.Studies of the activation of organic substrates by more than one transition metal in dinuclear organometallic complexes are increasingly being reported. 2 The interest in such complexes stems not only from their intriguing structural diversities 2,3 but also from their potential catalytic activity, 4 their possible importance in materials with conducting properties 5 and their role in bioinorganic chemistry. 6 Furthermore, metal-ligand activation in dinuclear complexes has not yet been studied systematically and an improved understanding of the scope and extent of such activations is very relevant. Two metals in close proximity sharing a common unsaturated ligand can cooperatively activate and assist in novel reactions, unique transformations and can cause severe structural deformations. 7 Examples are carbon-carbon bond-cleavage and coupling reactions, 8 sterically and/or electronically controlled sites of activity, 9 stabilization of reactive intermediates via co-ordination 1,10 and migratory movements of ligands or metal fragments. 11In our laboratories studies relating to heterobimetallic complexes with σ,π-bridged phenyl and thienyl ligands are of particular interest. 12 Recently we discovered an interesting activation mechanism surrounding a shared thienyl ligand which was π bonded to Cr(CO) 3 and σ bonded to Mn(CO) 5 in the 2 position. The two metal fragments irreversibly, and according to an intramolecular mechanism, exchanged σ,π co-ordination sites. 13 This novel conversion was a direct result of the metals being in electronic contact through the bridging thienyl ligand. These results prompted us further to investigate the extent of activation by σ-bonded early and late transition-metal substituents and their influence on thienyl ligands which are π bonded to Cr(CO) 3 . In this paper we describe the synthesis and characterization of dinuclear complexes with σ-bonded platinum() and gold() fragments in the 2 position of a bridging π-coordinated thienyl ligand.The platinum group metals show very high hydrodesulfurization (HDS) activity 14 and Maitlis and co-workers 15 recorded an oxidative insertion of Pt 0 into the C᎐S bond of thiophenes. Unfortunately for HDS purposes the reverse reaction, regenerating thiophene, is favoured. Efforts to prepare platinum() complexes of 2-(2...

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“…A list of successful nucleophiles includes stabilized and unstabilized organolithiums [2,130], Grignard reagents [131], a variety of hydride reagents [132] and cyanide [133,134]. Sensitive functionality readily tolerate the mild complexation and demetallation conditions.…”

Section: Addition/oxidation With Arene-mn(co) 3 Cation Complexesmentioning

confidence: 99%

“…Reaction of 132 with the esterenolate 137 results in diastereoselective aldol addition, which is followed by a Brook rearrangement and cyclization to yield Scheme 23 Synthesis of macrocarpal C (131) according to Iwata Scheme 24 Use of 132 as a chiral building block for the synthesis of (+)-goniofufurone (134) and the taxol side chain analog 135 according to Hanaoka the spirocyclic product 138 as a single diastereomer (Scheme 25) [69]. Thus, a key problem of any synthesis of fredericamycin has been solved in an astonishingly easy fashion applying arene chromium chemistry.…”

Section: Scheme 22 Synthesis Of Oo-dimethylkorupensamine 125 Accordimentioning

confidence: 99%

Transition Metal Arene π-Complexes in Organic Synthesis and Catalysis

Kündig¹,

Böttcher²

2004

Topics in Organometallic Chemistry

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Ring metallation of thiophenechromium tricarbonyl with butyllithium

Cited by 22 publications

References 2 publications

Synthesis and structure of bimetallic complexes with σ,π-bridged monocarbene ligands

Synthesis and structure of bimetallic complexes with σ,π-bridged monocarbene ligands

Synthesis and structure of bimetallic complexes with σ,π-bridging thienyl and benzothienyl ligands

Transition Metal Arene π-Complexes in Organic Synthesis and Catalysis

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