CO Cleavage Promoted by Acetylide Addition to Vinyliminium Diiron Complexes

Busetto, Luigi; Marchetti, Fabio; Zacchini, Stefano; Zanotti, Valerio

doi:10.1002/ejic.200500927

Cited by 17 publications

(17 citation statements)

References 28 publications

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“…The overall fragment behaves as a sixelectron donor towards the metal centres, through the carbon atoms of the allylidene chain and the oxygen of the carbonyl function. More precisely, the bridging C 3 unit is s-coordinated to Fe (2) [Fe(2)eC(12) 1.940(5) Å] and h 3 -coordinated to Fe(1) [Fe(1)eC (12) 2.096(4) Å; Fe(1)eC(13) 2.005(4) Å; Fe(1)eC(14)-2.145(4) Å], in an allyl-like fashion; in agreement with this, the C(12)eC (13) and C (13)eC (14) interactions [1.428(6) and 1.441(6) Å, respectively], corresponding to C 1 eC 2 and C 2 eC 3 in Scheme 2, are very similar. The carboxylic ester group is O-coordinated to Fe(2) [Fe(2)-O(15) 2.022(3) Å] and, therefore, the C(15)-O(15) interaction [1.235(5) Å] appears slightly elongated respect to a pure double bond.…”

Section: Resultssupporting

confidence: 66%

“…A closer analogy is represented by the reaction shown in Scheme 4, involving a vinyliminium complex very similar to 1. In this latter case, the addition of acetylide promotes FeeCO cleavage and results in the incorporation and rearrangement of all the fragments, including the acetylide unit, into the bridging frame [13].…”

Section: Tablementioning

confidence: 99%

“…All non-hydrogen atoms were refined with anisotropic displacement parameters, unless otherwise stated. H-atoms were placed in calculated positions, except for H (13) and H(43) which were located in the Fourier map. H-atoms were treated isotropically using the 1.2 fold U iso value of the parent atom except methyl protons, which were assigned the 1.5 fold U iso value of the parent C-atoms.…”

Section: X-ray Crystallography Formentioning

confidence: 99%

See 2 more Smart Citations

Assembly and incorporation of a CO2Me group into a bridging vinyliminium ligand in a diiron complex

Renili

Marchetti

Zacchini

et al. 2011

Journal of Organometallic Chemistry

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Section: Resultssupporting

confidence: 66%

Section: Tablementioning

confidence: 99%

Section: X-ray Crystallography Formentioning

confidence: 99%

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Assembly and incorporation of a CO2Me group into a bridging vinyliminium ligand in a diiron complex

Renili

Marchetti

Zacchini

et al. 2011

Journal of Organometallic Chemistry

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“…Both the acyl fragment and the O atom, consequently generated, are then incorporated in the bridging ligand, leading to the formation of the complex 135. [107] The overall result is a significant growth of the bridging hydrocarbyl chain.…”

Section: Wwwchemeurjorgmentioning

confidence: 99%

CC Bond Formation in Diiron Complexes

Mazzoni

Salmi

Zanotti

2012

Chemistry A European J

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The growing effort to design new sustainable synthetic methodologies, based on readily available and environmentally friendly transition metals, has boosted research on iron complexes. This review article focuses on C-C-bond-forming reactions occurring at bridging ligands in diiron complexes, aimed at evidencing distinctive aspects and advantages associated with the presence of two adjacent iron centres. A number of diiron-mediated C-C-bond-forming reactions reported in the literature, including nucleophilic and electrophilic additions and insertion and cycloaddition reactions, have been accumulated over the years, which, together with more recent developments, indicate that diiron complexes might provide promising alternatives to precious metals in the challenging field of metal-promoted C-C bond formation.

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“…In a few cases, the ancillary ligands CO [20] and Cp [21] are also involved, as in the example shown in Scheme 7.…”

Section: Nucleophilic Additionsmentioning

confidence: 99%

Reactions of bridging C3 ligands in diiron complexes: Unconventional routes to new functionalized organic frames

Zanotti

2010

Pure and Applied Chemistry

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Diiron complexes containing C 3 ligands, such as vinyliminium and vinylalkylidene bridging units, display unusual reaction patterns, not observed when the same organic fragments are bound to a single metal center, or not coordinated. Bridging vinyliminium complexes [Fe 2 {μ-η 1 :η 3 -C(NMe 2 )CH=CR}(μ-CO)(CO)(Cp) 2 ][SO 3 CF 3 ] undergo nucleophilic addition at the iminium C or at α-C position, which is uncommon since non-coordinated vinyliminium species generally undergo conjugated (Michael type) nucleophilic attack. Likewise, bridging vinyliminium ligands undergo new and unusual transformations consisting of the deprotonation and replacement of the α-CH by a variety of functional groups. These reactions, resulting in the formation of C-C and C-heteroatom single and double bonds, produce new bridging ligands of the type [μ-C(NMe 2 )C(X)CR) (X = S, O, Se, SPh, CNMe, NNCHCO 2 Me].Removal of the vinylalkylidene ligands from the bridging coordination is achieved by a [3 + 2] cycloaddition with alkynes. The reaction leads to the formation of ferrocenes containing one polysubstituted Cp ring, which results from the cycloaddition of the bridging C 3 ligand with alkynes. This result suggests a new possible route for the synthesis of polyfunctionalized ferrocenes. Bridging C 3 ligands in diiron complexes 1559Scheme 4Scheme 5 Deprotonation of bridging vinyliminium complexesDeprotonation in the α-position of iminium compounds leads to enamines (a, Scheme 8). These are intermediates in enamine catalysis, a powerful synthetic tool for α-C substitution reactions [22]. Conjugated iminium groups (α,β-unsaturated iminium species) do not undergo α-CH deprotonation, but rather react as Michael acceptors. In theory, they can undergo γ-functionalization via dienamine intermediates, but this possibility has been, so far, scarcely investigated [23]. V. ZANOTTI

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CO Cleavage Promoted by Acetylide Addition to Vinyliminium Diiron Complexes

Cited by 17 publications

References 28 publications

Assembly and incorporation of a CO2Me group into a bridging vinyliminium ligand in a diiron complex

Assembly and incorporation of a CO2Me group into a bridging vinyliminium ligand in a diiron complex

CC Bond Formation in Diiron Complexes

Reactions of bridging C3 ligands in diiron complexes: Unconventional routes to new functionalized organic frames

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