Cyclic Enolates of Ni and Pd: Equilibrium between C‐ and O‐Bound Tautomers and Reactivity Studies

Cámpora, Juan; Maya, Celia; Carmona, Ernesto; Gutiérrez, Enrique; Ruíz, Cristina Mayor; Graiff, Claudia; Tiripicchio, António

doi:10.1002/chem.200500622

Cited by 43 publications

(23 citation statements)

References 88 publications

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“…This is not surprising, but suggests care must be taken when applying reasoning from carbocycles and 'ordinary' heterocycles to metallocycles. In contradistinction to the above case of 3-nickela-1-indanone and the nearly isoenergetic isomeric 3-methylene-1-nickela-isobenzofuran, the isoelectronic Pd species uneqivocally prefers the carbonbonded enolate 277 . …”

Section: Group 9: Cobalt Rhodium and Iridiummentioning

confidence: 93%

“…in having the two coexisting isomeric forms. The 3-nickela-1-indanone complex 55 (Cbonded) and the isomeric 3-methylene-1-nickela-isobenzofuran complex 56 (O-bonded) are in equilibrium with each other 277 in approximately equal amounts and so necessarily they have nearly equal Gibbs free energies. Temperature-dependent measurements show the C-isomer is more stable by 1.1 ± 0.4 kJ mol −1 .…”

Section: Group 9: Cobalt Rhodium and Iridiummentioning

confidence: 99%

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Thermochemical Considerations of Metal Enolates

Liebman

Slayden

2010

Patai's Chemistry of Functional Groups

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Introduction Group 1: Lithium, Sodium, Potassium, Rubidium and Cesium Group 2: Beryllium, Magnesium, Calcium, Strontium and Barium Group 13: Aluminum, Gallium, Indium and Thallium Group 14: Tin and Lead Group 11: Copper, Silver and Gold Group 12: Zinc, Cadmium and Mercury Group 3: Scandium, Yttrium and the Lanthanides Actinides Group 4: Titanium, Zirconium and Hafnium Group 5: Vanadium, Niobium and Tantalum Group 6: Chromium, Molybdenum and Tungsten Group 7: Manganese and Rhenium Group 8: Iron, Ruthenium and Osmium Group 9: Cobalt, Rhodium and Iridium Group 10: Nickel, Palladium and Platinum

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Section: Group 9: Cobalt Rhodium and Iridiummentioning

confidence: 93%

Section: Group 9: Cobalt Rhodium and Iridiummentioning

confidence: 99%

Thermochemical Considerations of Metal Enolates

Liebman

Slayden

2010

Patai's Chemistry of Functional Groups

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“…The carbonyl group‐containing organometallic intramolecular coordination five‐membered ring compounds prepared by orthometalation are shown in equation (4). Sixteen kinds of elements and 79 types of compounds are included in the Cambridge Structural Database 18–52. For example, the orthometalations of alkyl phenyl ketone [equation (5)29], aryl phenyl ketone [equation (6)36], benzaldehyde [equation (7)35], phenyl amide [equation (8)46], etc.…”

Section: Synthesis Of Carbonyl Group‐containing Organometallic Intrammentioning

confidence: 99%

Carbonyl group‐containing organometallic intramolecular‐coordination five‐membered ring compounds

Omae¹

2010

Applied Organom Chemis

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Carbonyl group-containing organometallic intramolecular-coordination five-membered ring compounds are easily synthesized by the following five reaction methods: (1) cyclometalation, especially, orthometalation reactions; (2) the reactions of the moieties of an unsaturated carbon-carbon bond attached to a carbonyl group (C C-CO, C C-CO); (3) the reactions of an unsaturated carbon-carbon bond with carbon monoxide (C C and CO, C C and CO); (4) carbonylative ring expansion reactions; and (5) others. These compounds are very easily and regio-specifically synthesized with many kinds of metal compounds, including both transition metals and main group metals. Many of such the reactions are easily applied to organic syntheses.

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“…Although the mechanisms of the decompositions of metal alkyl complexes have been studied in detail, much less information has been gained on the rates and mechanism of the decomposition of transition metal enolate complexes. With few exceptions,23,24 published studies on the structure and stability of transition metal enolate complexes have involved those that lack β-hydrogens 25,26. Such complexes are rarely the types of enolate species involved in the catalytic processes described above.…”

Section: Introductionmentioning

confidence: 99%

Mechanistic Study of β-Hydrogen Elimination from Organoplatinum(II) Enolate Complexes

Alexanian

Hartwig

2008

J. Am. Chem. Soc.

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A detailed mechanistic investigation of the thermal reactions of a series of bisphosphine alkylplatinum(II) enolate complexes is reported. The reactions of methylplatinum enolate complexes in the presence of added phosphine form methane and either free or coordinated enone, depending on the steric properties of the enone. Kinetic studies were conducted to determine the relationship between the rates and mechanism of β-hydrogen elimination from enolate complexes and the rates and mechanism of β-hydrogen elimination from alkyl complexes. The rates of reactions of the enolates were inversely dependent on the concentration of added phosphine, indicating that β-hydrogen elimination from the enolate complexes occurs after reversible dissociation of a phosphine. A normal, primary kinetic isotope effect was measured, and this effect was consistent with ratelimiting β-hydrogen elimination or C-H bond-forming reductive elimination to form methane. Reactions of substituted enolate complexes were also studied to determine the effect of the steric and electronic properties of the enolate complexes on the rates of β-hydrogen elimination. These studies showed that reactions of the alkylplatinum enolate complexes were retarded by electron-withdrawing substituents on the enolate and that reactions of enolate complexes possessing alkyl substituents at the β-position occurred at rates that were similar to those of complexes lacking alkyl substituents at this position. Despite the trend in electronic effects on the rates of reactions of enolate complexes and the substantial electronic differences between an enolate and an alkyl ligand, the rates of decomposition of the enolate complexes were similar to those of the analogous alkyl complexes. To the extent that the rates of reaction of the two types of complex are different, those involving β-hydrogen elimination from the enolate ligand were faster. A difference between the identity of the rate-determining step for decomposition of the two classes of complexes and an effect of stereochemistry on the selectivity for β-hydrogen elimination are possible origins of the observed phenomena.

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Cyclic Enolates of Ni and Pd: Equilibrium between C‐ and O‐Bound Tautomers and Reactivity Studies

Cited by 43 publications

References 88 publications

Thermochemical Considerations of Metal Enolates

Thermochemical Considerations of Metal Enolates

Carbonyl group‐containing organometallic intramolecular‐coordination five‐membered ring compounds

Mechanistic Study of β-Hydrogen Elimination from Organoplatinum(II) Enolate Complexes

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