Preparation of 1,2,3,4-Tetramethylpentafulvene by Hydride Anion Abstraction from Lithium Pentamethylcyclopentadienide Employing Tritylchloride

Döring, Steve; Erker, Gerhard

doi:10.1055/s-2001-9754

Cited by 22 publications

(14 citation statements)

References 8 publications

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“…Commercially available C 5 Me 5 H was thus converted in one pot to LiC 5 Me 4 CH 2 PEt 2 (ref. 26). This salt was treated with [Cp*FeCl] 2 generated in situ to give FcP * in ~55% isolated yield as a bright yellow solid (Fig.…”

Section: Resultsmentioning

confidence: 99%

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Combining acid–base, redox and substrate binding functionalities to give a complete model for the [FeFe]-hydrogenase

2011

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Some enzymes function by coupling substrate turnover with electron transfer from a redox cofactor such as ferredoxin. In the [FeFe]-hydrogenases, nature’s fastest catalysts for the production and oxidation of H2, the one-electron redox by a ferredoxin complements the one-electron redox by the diiron active site. In this Article, we replicate the function of the ferredoxins with the redox-active ligand Cp*Fe(C5Me4CH2PEt2) (FcP*). FcP* oxidizes at mild potentials, in contrast to most ferrocene-based ligands, which suggests that it might be a useful mimic of ferredoxin cofactors. The specific model is Fe2[(SCH2)2NBn](CO)3(FcP*)(dppv) (1), which contains the three functional components of the active site: a reactive diiron centre, an amine as a proton relay and, for the first time, a one-electron redox module. By virtue of the synthetic redox cofactor, [1]2+ exhibits unique reactivity towards hydrogen and CO. In the presence of excess oxidant and base, H2 oxidation by [1]2+ is catalytic.

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Section: Resultsmentioning

confidence: 99%

“…Li[C 5 Me 4 CH 2 PEt 2 ] was prepared by slow addition of 22 ml of 2,3,4,5-tetramethylfulvene 26 solution (0.21 M in toluene) to 0.49 g (4.56 mmol) of LiPEt 2 in 100 ml of THF at −78 °C. The reaction mixture was allowed to warm to room temperature overnight, resulting in a pale yellow solution of Li[C 5 Me 4 CH 2 PEt 2 ].…”

Section: Methodsmentioning

confidence: 99%

Combining acid–base, redox and substrate binding functionalities to give a complete model for the [FeFe]-hydrogenase

2011

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“…1 H NMR (300 MHz, C 6 D 6 ) d 1.95 (s, 6H, CH 3 ), 1.6 (s, 6H, CH 3 ) and 1.1 (s, 4H, CH 2 ). 13 (2-P,P-Diethylphosphinoethyl)cyclopentadienyl lithium 23 LiPEt 2 (0.77 g, 6.5 mmol) was dissolved in THF (40 cm 3 ) and refluxed with bicyclo [2,4]hepta-1,3-diene (0.65 g, 7.03 mmol) for 1 h. The solvent was removed in vacuo and the residue washed with petroleum (50 cm 3 × 2) to leave a white solid (0.98 g, 80% yield). 1 phase.…”

Section: Methodsmentioning

confidence: 99%

The synthesis, characterisation and reactivity of 2-phosphanylethylcyclopentadienyl complexes of cobalt, rhodium and iridium

et al. 2006

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2-Phosphanylethylcyclopentadienyl lithium compounds, Li[C(5)R'(4)(CH(2))(2)PR(2)] (R = Et, R' = H or Me, R = Ph, R' = Me), have been prepared from the reaction of spirohydrocarbons C(5)R'(4)(C(2)H(4)) with LiPR(2). C(5)Et(4)HSiMe(2)CH(2)PMe(2), was prepared from reaction of Li[C(5)Et(4)] with Me(2)SiCl(2) followed by Me(2)PCH(2)Li. The lithium salts were reacted with [RhCl(CO)(2)](2), [IrCl(CO)(3)] or [Co(2)(CO)(8)] to give [M(C(5)R'(4)(CH(2))(2)PR(2))(CO)] (M = Rh, R = Et, R' = H or Me, R = Ph, R' = Me; M = Ir or Co, R = Et, R' = Me), which have been fully characterised, in many cases crystallographically as monomers with coordination of the phosphorus atom and the cyclopentadienyl ring. The values of nu(CO) for these complexes are usually lower than those for the analogous complexes without the bridge between the cyclopentadienyl ring and the phosphine, the exception being [Rh(Cp'(CH(2))(2)PEt(2))(CO)] (Cp' = C(5)Me(4)), the most electron rich of the complexes. [Rh(C(5)Et(4)SiMe(2)CH(2)PMe(2))(CO)] may be a dimer. [Co(2)(CO)(8)] reacts with C(5)H(5)(CH(2))(2)PEt(2) or C(5)Et(4)HSiMe(2)CH(2)PMe(2) (L) to give binuclear complexes of the form [Co(2)(CO)(6)L(2)] with almost linear PCoCoP skeletons. [Rh(Cp'(CH(2))(2)PEt(2))(CO)] and [Rh(Cp'(CH(2))(2)PPh(2))(CO)] are active for methanol carbonylation at 150 degrees C and 27 bar CO, with the rate using [Rh(Cp'(CH(2))(2)PPh(2))(CO)] (0.81 mol dm(-3) h(-1)) being higher than that for [RhI(2)(CO)(2)](-) (0.64 mol dm(-3) h(-1)). The most electron rich complex, [Rh(Cp'(CH(2))(2)PEt(2))(CO)] (0.38 mol dm(-3) h(-1)) gave a comparable rate to [Cp*Rh(PEt(3))(CO)] (0.30 mol dm(-3) h(-1)), which was unstable towards oxidation of the phosphine. [Rh(Cp'(CH(2))(2)PEt(2))I(2)], which is inactive for methanol carbonylation, was isolated after the methanol carbonylation reaction using [Rh(Cp'(CH(2))(2)PEt(2))(CO)]. Neither of [M(Cp'(CH(2))(2)PEt(2))(CO)] (M = Co or Ir) was active for methanol carbonylation under these conditions, nor under many other conditions investigated, except that [Ir(Cp'(CH(2))(2)PEt(2))(CO)] showed some activity at higher temperature (190 degrees C), probably as a result of degradation to [IrI(2)(CO)(2)](-). [M(Cp'(CH(2))(2)PEt(2))(CO)] react with MeI to give [M(Cp'(CH(2))(2)PEt(2))(C(O)Me)I] (M = Co or Rh) or [Ir(Cp'(CH(2))(2)PEt(2))Me(CO)]I. The rates of oxidative addition of MeI to [Rh(C(5)H(4)(CH(2))(2)PEt(2))(CO)] and [Rh(Cp'(CH(2))(2)PPh(2))(CO)] are 62 and 1770 times faster than to [Cp*Rh(CO)(2)]. Methyl migration is slower, however. High pressure NMR studies show that [Co(Cp'(CH(2))(2)PEt(2))(CO)] and [Cp*Rh(PEt(3))(CO)] are unstable towards phosphine oxidation and/or quaternisation under methanol carbonylation conditions, but that [Rh(Cp'(CH(2))(2)PEt(2))(CO)] does not exhibit phosphine degradation, eventually producing inactive [Rh(Cp'(CH(2))(2)PEt(2))I(2)] at least under conditions of poor gas mixing. The observation of [Rh(Cp'(CH(2))(2)PEt(2))(C(O)Me)I] under methanol carbonylation conditions suggests that the rhodium centre has become so electron ...

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“…1,2,3,4-Tetramethylfulvene 44 is an important building block in organometallic chemistry (see section ), and several syntheses have been reported (Scheme ). Jutzi prepared this compound starting from pentamethylcyclopentadienyl bromide 45 . , Ogino and Erker obtained the compound by hydride abstraction from LiCp* using a trityl cation. , Later, Krut’ko and co-workers investigated the formation of 44 from (trimethylsilyl) tetramethyl cyclopentadienide anion 47 by the reaction of formaldehyde through a combined experimental and theoretical study …”

Section: Synthesis Of Pentafulvenesmentioning

confidence: 99%

Recent Advances in the Chemistry of Pentafulvenes

et al. 2017

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Pentafulvenes are a unique class of compounds that originally attracted attention due to their propensity to display nonbenzenoid aromaticity. Subsequently, they were recognized as valuable synthons for the construction of a wide range of compounds by virtue of their ability to display multiple cycloaddition profiles. Naturally, this area of organic chemistry has experienced rapid growth over the last five decades, fueled by elegant work showcasing the unique reactivity of pentafulvenes in a plethora of cycloaddition reactions. In this Review, we have attempted to provide a systematic account of the methods for the generation of pentafulvenes, their rich and varied cycloaddition chemistry, organometallic reactions, and theoretical studies that support their versatility. Further, we have highlighted their applications in the synthesis of a variety of complex structural frameworks. It is our conviction that this Review will be useful to a wide range of chemists, and will spur further research in this promising area.

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Preparation of 1,2,3,4-Tetramethylpentafulvene by Hydride Anion Abstraction from Lithium Pentamethylcyclopentadienide Employing Tritylchloride

Cited by 22 publications

References 8 publications

Combining acid–base, redox and substrate binding functionalities to give a complete model for the [FeFe]-hydrogenase

Combining acid–base, redox and substrate binding functionalities to give a complete model for the [FeFe]-hydrogenase

The synthesis, characterisation and reactivity of 2-phosphanylethylcyclopentadienyl complexes of cobalt, rhodium and iridium

Recent Advances in the Chemistry of Pentafulvenes

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