Mononuclear Biscarbene Complexes by Direct Nucleophile Addition to a CO Ligand of Fischer Arylcarbene Complexes

Barluenga, José; Trabanco, Andrés A.; Pérez-Sánchez, Iván; Campa, Raquel de la; Flórez, Josefa; García-Granda, Santiago; Aguirre, Ángel

doi:10.1002/chem.200800452

Cited by 12 publications

(9 citation statements)

References 46 publications

(11 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…On the other hand, using lithium morpholin‐4‐ide and alkoxy carbene complexes with bulky substituents (R 1 = menthyl, Scheme ) results in a C–C coupling reaction to give α‐alkoxy acetamides presumably via biscarbenes (Scheme d) . In the absence of a nucleophile or alkyne, simple thermolysis of carbene complexes yields the olefin as formal carbene‐carbene coupling product as already reported by Fischer (Scheme e) , …”

Section: Introductionsupporting

confidence: 60%

“…[26] On the other hand, using lithium morpholin-4-ide and alkoxy carbene complexes with bulky substituents (R 1 = menthyl, Scheme 1) results in a C-C coupling reaction to give α-alkoxy acetamides presumably via biscarbenes (Scheme 1d). [27] In the absence of a nucleophile or alkyne, simple thermolysis of carbene complexes yields the olefin as formal carbene-carbene coupling product as already reported by Fischer (Scheme 1e). [28,29] In this study, we show that the thermally activated reaction of 1 with the weak nucleophile Fc-NH 2 gives 2,N-diferrocenyl acetamide Fc-CH 2 -CO-NH-Fc (2) (Scheme 1f) instead of the initially intended (amino ferrocenyl)(ferrocenyl)carbene complex [26] (Scheme 1c).…”

Section: Introductionsupporting

confidence: 59%

“…Indeed, biscarbene complexes have been reported by Fischer using M(CO) 6 and LiPMe 2 after methylation in very low yield . More recently, Barluenga succeeded in isolating biscarbene complexes starting from chromium and tungsten alkoxy carbenes and strong heteronucleophiles such as amides or alkoxides after alkylation (Scheme d) . Heating these (aminoaryl)(alkoxyalkenyl)biscarbene tungsten complexes to 35 °C furnished the olefinic carbene‐carbene coupling products in good yields (Scheme d) …”

Section: Resultsmentioning

confidence: 99%

“…[27] Heating these (aminoaryl)(alkoxyalkenyl)biscarbene tungsten complexes to 35°C furnished the olefinic carbene-carbene coupling products in good yields (Scheme 1d). [27] A fully analogous reaction (without the intermediate alkylation step) might be operative here. Amino ferrocene, although a weak nucleophile, attacks a carbonyl ligand cis to the carbene ligand forming zwitterion I (Scheme 2 [26,[42][43][44][45] The XH•••Fe bond dissociation energy can amount up to 13 kJ•mol -1 .…”

Section: Mechanistic Considerations On the Formation Ofmentioning

confidence: 99%

See 3 more Smart Citations

Unexpected C–C Bond Formation with a Ferrocenyl Fischer Carbene Complex

Veit

Seibert

Förster

et al. 2020

Zeitschrift anorg allge chemie

View full text Add to dashboard Cite

Thermolysis of (OC)5Cr(C(OEt)(Fc)) (1) gives 2,N‐diferrocenyl acetamide Fc–CH2–CO–NH–Fc (2) in the presence of amino ferrocene Fc‐NH2. In the absence of a nucleophile, 4‐ethoxy‐2,3,4‐triferrocenyl‐cyclobut‐2‐enone (3) forms from 1 under thermal activation. Single crystal X‐ray diffraction, NMR spectroscopy and mass spectrometry unambiguously confirm the structure of both unexpected products. Quantum chemical calculations and kinetic experiments by mass spectrometry and IR spectroscopy help to propose conceivable pathways to their formation.

show abstract

Section: Introductionsupporting

confidence: 60%

Section: Introductionsupporting

confidence: 59%

Section: Resultsmentioning

confidence: 99%

Section: Mechanistic Considerations On the Formation Ofmentioning

confidence: 99%

See 2 more Smart Citations

Unexpected C–C Bond Formation with a Ferrocenyl Fischer Carbene Complex

Veit

Seibert

Förster

et al. 2020

Zeitschrift anorg allge chemie

View full text Add to dashboard Cite

show abstract

“…(17)(18)(19) Mononuclear bis-carbene complexes with alkoxy substituents are scarce and much more reactive. (20) The few bisalkoxycarbene chelates known and reported many years ago are symmetrically substituted compounds. The identical carbene ligands displayed nonselective reactivity patterns at both carbene carbon centers.…”

mentioning

confidence: 99%

Fischer Dinuclear and Mononuclear Bis-Carbene Complexes of Thiophene and Thiophene Derivatives

et al. 2012

View full text Add to dashboard Cite

The reaction of dilithiated thiophene and thiophene derivatives with group 6 transition metal carbonyl precursors and subsequent alkylation afforded linearly arranged Fischer 2,5-bis-carbene and the rare unsymmetrical 2,3-bis-carbene chelated complexes. The latter requires a second lithiation to occur at an adjacent, less reactive site on the thiophene ring. The control of reactivity sites was investigated and achieved by either blocking more reactive positions with substituents or activating less reactive positions by lithium-halogen exchange reactions. A series of Fischer bis-carbene chelates were synthesized by manipulating the above variables. Structural features of Fischer mono-carbene, mononuclear bis-carbene, and bis-carbene chelated complexes were studied by IR, NMR, and singlecrystal X-ray diffraction.

show abstract