A Model Structure for the Resting State of Cyanocuprate Reagents R2Cu(CN)Li2. The X-ray Crystal Structure of [Ar2Cu(CN)Li2(THF)4]∞1

Koten, Gerard van; Kronenburg, Claudia M. P.; Jastrzebski, Johann T. B. H.; Spek, Anthony L.

doi:10.1021/ja9802448

Cited by 81 publications

(66 citation statements)

References 33 publications

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“…X-ray structural studies show 4 to be an ionic species comprising a centrosymmetric [Cu 2 Li 4 (CN) 4 [7] and [(2-C 6 H 4 CH 2 NMe 2 ) 2 Cu{Li(THF) 2 } 2 -CN] ϱ . [8] Low temperature (Ϫ100°C) 1 H-decoupled 13 C NMR spectroscopy carried out on an aliquot of the CuCN ϩ PhLi ϩ PPh 3 reaction mix after stirring for 10 min at 0°C in toluene/THF solution shows singlets at δ ϭ 174.20 and 144.27 ppm for the phenyl ipso carbon and the cyanide carbon resonances, respectively. The chemical shift of the ipso carbon is therefore downfield from the value observed for PhCuCNLi in the absence of phosphane (δ ϭ 166.05 ppm), [3] indicating some structural change has occurred.…”

Section: Resultsmentioning

confidence: 99%

Lithium Cyanocuprates: Structural Studies of a Phosphane Adduct of a “Lower‐Order” Lithium Cyanocuprate

Davies

Hornauer

2004

Eur J Inorg Chem

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Addition of PPh3 to the “lower‐order” cyanocuprate PhCuCNLi results in a significant increase in reactivity in 1,4‐Michael addition reactions. This is explained by a marked structural change in the cyanocuprate reagent, observed in both THF solution and the solid state, to give [Ph2Cu]− cuprate anions and a [Cu2Li4(CN)4(PPh3)4(THF)10]2+ dication. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005)

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Section: Resultsmentioning

confidence: 99%

Lithium Cyanocuprates: Structural Studies of a Phosphane Adduct of a “Lower‐Order” Lithium Cyanocuprate

Davies

Hornauer

2004

Eur J Inorg Chem

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“…[11] The X-ray crystal structures of R 2 CuLiĹ iCN contain ionic subunits R 2 Cu À and Li 2 CN , [55,56] as proposed by one of us in 1990. [8] Finally, structural proposals must be based upon spectroscopic data or X-ray analysis, not reactivity data.…”

Section: Reactions With Cyimentioning

confidence: 99%

Re-evaluation of Organocuprate Reactivity: Logarithmic Reactivity Profiles for Iodo- versus Cyano-Gilman Reagents in the Reactions of Organocuprates with 2-Cyclohexenone and Iodocyclohexane

Bertz¹,

Chopra

Eriksson

et al. 1999

Chem. Eur. J.

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Iodo-Gilman reagents Me 2 -CuLi´LiI, Bu 2 CuLi´LiI, and BuThCuLi´LiI and cyano-Gilman reagents (ne Â e ªhigher order cyanocupratesº Me 2 CuLi´LiCN, Bu 2 CuLi´LiCN, and BuThCuLi´LiCN react with 2-cyclohexenone at various rates, which depend upon the R groups (Me, Bu, Th thienyl), Li salt (LiI vs. LiCN), solvent (ether vs. THF), and amount of trimethylsilyl chloride (TMSCl) additive. The effect of the Li salt (CuI vs. CuCN precursor) is less than that of solvent or TMSCl. The butylcuprate-iodocyclohexane reaction has also been examined as a function of Li salt, solvent, and TMSCl additive, and similar effects are observed. The reactivity matrix R with elements r i,j is a convenient way to store and present a large amount of relative reactivity data. Entry r i,j is the ratio of the rate with reagent i to the rate with reagent j, which we approximate by using yields measured after a short time (4 s). The logarithmic reactivity profile (LRP) provides an efficient means for determining yields under conditions where such comparisons are valid. The results of a large number of 4-point LRPs and related reactions are tabulated and analyzed to provide a clearer picture of organocuprate reactivity.

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“…Moreover, recent spectroscopic studies (EXAFS [9][10][11] and NMR [12][13][14]) and molecular weight determinations [15] seemed also to support the structural proposals C and D.…”

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confidence: 73%

Structure and reactivity of cyanocuprates containing the monoanionic C,N-chelating aminoaryl ligand [C6H4CH2NMe2-2]−

2000

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[2]. In addition to this proposal, three other structures were also postulated: a monoanionic copper species (B) [3,4], a neutral monomeric copper species (C) [5,6] and a 'cyano-Gilman' cuprate (D) [7].The discussion on the structural aspects of 2:1 cyanocuprates has mainly been focused on proposals C and D, although arguments were put forward to support each of the * Corresponding author. Tel.: q31-30-2531813; fax: q31-30-2523615; e-mail: g.vankoten@chem.uu.nl four structures [8]. Moreover, recent spectroscopic studies (EXAFS [9][10][11]) and molecular weight determinations [15] seemed also to support the structural proposals C and D.

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A Model Structure for the Resting State of Cyanocuprate Reagents R₂Cu(CN)Li₂. The X-ray Crystal Structure of [Ar₂Cu(CN)Li₂(THF)₄]_∞¹

Cited by 81 publications

References 33 publications

Lithium Cyanocuprates: Structural Studies of a Phosphane Adduct of a “Lower‐Order” Lithium Cyanocuprate

Lithium Cyanocuprates: Structural Studies of a Phosphane Adduct of a “Lower‐Order” Lithium Cyanocuprate

Re-evaluation of Organocuprate Reactivity: Logarithmic Reactivity Profiles for Iodo- versus Cyano-Gilman Reagents in the Reactions of Organocuprates with 2-Cyclohexenone and Iodocyclohexane

Structure and reactivity of cyanocuprates containing the monoanionic C,N-chelating aminoaryl ligand [C6H4CH2NMe2-2]−

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