Rearrangement of cyclooctyne to 1,2-cyclooctadiene within the coordination sphere of CpMn(CO)2

Coughlan, Siobhan; Yang, Gilbert K.

doi:10.1016/0022-328x(93)80151-z

Cited by 18 publications

(6 citation statements)

References 40 publications

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“…It was identified by mass spectrometry and shows a strong IR band at 1963 cm À1 . Similar intermediates with an alkyne unit bound to a CpM(CO) n fragment are reported in the literature for M = Co, n = 1 [6,7], and M = Mn, n = 2 [8,9]. Also complexes of the type ArCr(CO) 2 (alkyne) have been reported [8,[10][11][12].…”

Section: Synthesismentioning

confidence: 59%

Photolysis of dicarbonyl(cyclopentadiene)rhodium complexes with a pendent alkyne unit

Schaefer

Gleiter

Röminger

2007

Journal of Organometallic Chemistry

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Section: Synthesismentioning

confidence: 59%

Photolysis of dicarbonyl(cyclopentadiene)rhodium complexes with a pendent alkyne unit

Schaefer

Gleiter

Röminger

2007

Journal of Organometallic Chemistry

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“…The isomerization of preformed metal−alkyne complexes to allenes can be promoted using acid, 9 alumina, 10 or silica. 11 In elegant mechanistic studies, Casey and co-workers described acid-promoted isomerization of alkyne complexes to allene complexes. Both 1-metallacyclopropene 8 and η 1 -vinyl species 3c were suggested as key intermediates in the isomerization mechanism.…”

mentioning

confidence: 99%

“…Both ReCl(N 2 )(dppe) 2 and RhCl(C 2 H 4 )(As( i -Pr) 3 ) 2 have been shown to form allenes upon reaction with internal alkynes. The isomerization of preformed metal–alkyne complexes to allenes can be promoted using acid, alumina, or silica . In elegant mechanistic studies, Casey and co-workers described acid-promoted isomerization of alkyne complexes to allene complexes.…”

mentioning

confidence: 99%

Formation of Iridium(III) Allene Complexes via Isomerization of Internal Alkynes

Phadke

Findlater

2013

Organometallics

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Syntheses of the alkyne complexes (POCOP)Ir(η2-RCCR) (1-DPA, R = Ph; 1-Oct, R = C3H7; 1-Hex, R = C2H5; POCOP = 2,6-bis(di-tert-butylphosphonito)benzene) are reported. 1-DPA is stable in both the solid state and as a benzene solution; however, both 1-Oct and 1-Hex slowly isomerize to afford the corresponding allene complexes 2-Oct and 2-Hex, respectively. A single-crystal X-ray structure determination of 2-Oct confirmed the assignment of an iridium-bound allene isomerization product. The rates of isomerization were measured using NMR techniques over a range of temperatures to allow determination of thermodynamic parameters. Finally, in contrast to prior reports, initial mechanistic studies have indicated the isomerization process is not catalyzed by the presence of an acid.

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“…The strong base-induced isomerization of internal alkynes to allenes is commonly known [18,19,20,21] and transition metals are known to participate in such isomerizations [23]. Alkyne to allene isomerizations within the defined transition metal complexes are rather scarce, and in some cases require acid-basic promotion [24,25,26]. Instances of the thermally induced isomerization of an internal alkyne to an allene are limited to four reports, our own iridium system [17], and examples involving Ti [27], Re [28] and Os [29] complexes.…”

Section: Resultsmentioning

confidence: 99%

Isomerization of Internal Alkynes to Iridium(III) Allene Complexes via C–H Bond Activation: Expanded Substrate Scope, and Progress towards a Catalytic Methodology

Phadke

Findlater

2015

Molecules

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Abstract:The synthesis of a series of allene complexes (POCOP)Ir(η 2 -RC==CR') 1b-4b (POCOP = 2,6-bis(di-tert-butylphosphonito)benzene) via isomerization of internal alkynes is reported. We have demonstrated that the application of this methodology is viable for the isomerization of a wide variety of alkyne substrates. Deuterium labeling experiments support our proposed mechanism. The structures of the allene complexes 1b-4b were determined using spectroscopic data analysis. Additionally, the solid-state molecular structure of complex 2b was determined using single crystal X-ray diffraction studies and it confirmed the assignment of an iridium-bound allene isomerization product. The rates of isomerization were measured using NMR techniques over a range of temperatures to allow determination of thermodynamic parameters. Finally, we report a preliminary step towards developing a catalytic methodology; the allene may be liberated from the metal center by exposure of the complex to an atmosphere of carbon monoxide.

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Rearrangement of cyclooctyne to 1,2-cyclooctadiene within the coordination sphere of CpMn(CO)2

Cited by 18 publications

References 40 publications

Photolysis of dicarbonyl(cyclopentadiene)rhodium complexes with a pendent alkyne unit

Photolysis of dicarbonyl(cyclopentadiene)rhodium complexes with a pendent alkyne unit

Formation of Iridium(III) Allene Complexes via Isomerization of Internal Alkynes

Isomerization of Internal Alkynes to Iridium(III) Allene Complexes via C–H Bond Activation: Expanded Substrate Scope, and Progress towards a Catalytic Methodology

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