Cyclopropenation of organometallic vinylidene complexes

Lin, Ying‐Chih

doi:10.1016/s0022-328x(00)00726-9

Cited by 12 publications

(4 citation statements)

References 57 publications

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“…An examination of the crystal structure of 2c reveals that, as a consequence of the hydrogen bonding between the κ 1 -OAc group and the OH, the oxygen atom is in close proximity to the α-carbon of the vinylidene ligand (O(5)−C(1) 2.770 Å). There are manifold examples of related intramolecular cyclization reactions of 4- and 5-hydroxy-substituted vinylidene complexes to give metal carbene complexes, and formation of three-membered rings from the base-promoted cyclization of species containing vinylidene ligands MCC(Ph)CH 2 R to afford cyclopropenyl complexes is also well documented …”

Section: Resultsmentioning

confidence: 99%

Exploitation of a Chemically Non-innocent Acetate Ligand in the Synthesis and Reactivity of Ruthenium Vinylidene Complexes

2009

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Reaction of the ruthenium bis-acetate complex cis-Ru(κ2-OAc)2(PPh3)2 with a range of terminal alkynes HCCR (R = Ph, CO2Me, C{OH}Ph2, C{OH}Me2) results in the formation of the vinylidene complexes Ru(κ2-OAc)(κ1-OAc)(CCHR)(PPh3)2. The acetate ligands in these species are fluxional and, in the case where R = Ph, are undergoing fast exchange on the NMR time scale even at 195 K. In the case of the hydroxy-substituted complex Ru(κ2-OAc)(κ1-OAc)(CCHC{OH}Ph2)(PPh3)2 a hydrogen bond exists between the OH group on the γ-position of the vinylidene and the κ1-OAc ligand. This hydrogen bond inhibits the exchange of the OAc ligands, which now becomes slow on the NMR time scale at 215 K. In addition, and in contrast to the Cl-substituted analogues, elimination of water from the hydroxy vinylidene complex does not readily occur, possibly due to the presence of this hydrogen-bonding interaction. Instead, a slow reaction to form Ru(κ2-OAc)(κ1-OAc)(CO)(PPh3)2 is observed with the concomitant formation of H2CCPh2. An analogous process with Ru(κ2-OAc)(κ1-OAc)(CCHC{OH}Me2)(PPh3)2 affords H2CCMe2 and Ru(κ2-OAc)(κ1-OAc)(CO)(PPh3)2.

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Section: Resultsmentioning

confidence: 99%

Exploitation of a Chemically Non-innocent Acetate Ligand in the Synthesis and Reactivity of Ruthenium Vinylidene Complexes

2009

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“…We are interested in exploring the chemical reactivity of various metal vinylidene complexes commonly prepared by alkylation of metal acetylide complexes. However, in the reaction of methyliodide with the rhodium phenylacetylide complex, oxidative addition takes place preferentially followed by a reductive elimination to give the 1-phenyl-1-propyne.…”

Section: Introductionmentioning

confidence: 99%

Rhodium-Catalyzed Dimerization of Terminal Alkynes Assisted by MeI

et al. 2004

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Dimerization of terminal arylalkynes at ambient temperature catalyzed by Rh(CO)(PPh 3 ) 2 -Cl (2) in the presence of MeI leads to formation of enyne with high conversion and high regio-and stereoselectivity. A rhodium intermediate captured from oxidative addition of MeI was used for dimerization of alkyne with selectivity controlled by the use of solvents. In aprotic solvent (such as acetone, CH 2 Cl 2 , or THF) dimerization of terminal alkynes HCtC(p-C 6 H 4 X) (1, X ) H, a; NO 2 , b; C(O)H, c; Me, d; CN, e; NMe 2 , f; CF 3 , g; F, h; Br, i; I, j) leads to the (E)-1,4-disubstituted enynes 6 (a-k) in high selectivity. However, when MeOH is used as a solvent, the dimerization of 1-arylalkynes containing an electronwithdrawing group affords selectively the (Z)-1,4-disubstituted enyne 8. Requirement of the presence of MeI for this conversion indicates that the process presumably involves initially a six-coordinated rhodium methylacetylide intermediate. Oxidative addition of ICH 2 CN to 2 yielded the catalytically inactive six-coordinated complex Rh(CO)(PPh 3 ) 2 (CtCPh)(I)(CH 2 -CN) (5a). The analogous complex 5b with a p-nitro group on the phenyl acetylide ligand is characterized by X-ray diffraction analysis.

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“…However, metal complexes containing azirinyl ligands are rare, possibly due to the lack of suitable synthetic methods. We previously described a cyclization reaction by deprotonation of a cationic ruthenium vinylidene complex containing a −CH 2 R group at C β of the vinylidene ligand to give a metal complex containing a strained cyclopropenyl ligand . Using this strategy, we reported the preparation of several ruthenium cyclopropenyl complexes containing various substituents.…”

Section: Introductionmentioning

confidence: 99%

Preparation of Ruthenium Azirinyl Complexes and Reversed Regiospecificity of the Carbonyl Insertion Reaction

Hsu

Huang

et al. 2004

Organometallics

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Electrophilic addition of organic halides to [Ru] CN (1; [Ru] ) Cp(PPh 3 ) 2 Ru) gave the cationic isocyanide complexes {[Ru]CNCH 2 R}X (R ) CN, 2a; R ) CHdCH 2 , 2b; R ) Ph, 2c), which reacted with base (n-Bu 4 NOH or n-Bu 4 NF) to give the three-membered-ring azirinyl complexes. For the azirinyl complex with a phenyl group 3c, three isomers, assigned as ruthenium 2H-and 1H-azirinyl complexes, are observed at -20°C. Reaction of the methyl isocyanoacetate complex {[Ru]CtNCH 2 COOMe}X (2d) with n-Bu 4 NOH causes hydrolysis of the ester group to give the ruthenium oxazolone complex 4d. The insertion of the CdO group of acetone, aldehyde, ester, and amide into the C-C bond of the three-membered azirinyl ring of 3a-c yields a variety of five-membered oxazolinyl complexes 5-7. The regiospecificity of the insertion differs from that observed in the photochemically induced carbonyl insertion in the organic azirine system. The diastereoselectivity in the formation of 5-7 is controlled by steric effects. In the formation of the pentamethylcyclopentadienyl oxazolinyl ruthenium complex 7a*, the intermediate 8a* is isolated before cyclization. Molecular structures of 7a* and 8a* have been determined by single-crystal X-ray diffraction analysis. Treatment of 7 with hydride gave [Ru]CN and alcohol.

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Cyclopropenation of organometallic vinylidene complexes

Cited by 12 publications

References 57 publications

Exploitation of a Chemically Non-innocent Acetate Ligand in the Synthesis and Reactivity of Ruthenium Vinylidene Complexes

Exploitation of a Chemically Non-innocent Acetate Ligand in the Synthesis and Reactivity of Ruthenium Vinylidene Complexes

Rhodium-Catalyzed Dimerization of Terminal Alkynes Assisted by MeI

Preparation of Ruthenium Azirinyl Complexes and Reversed Regiospecificity of the Carbonyl Insertion Reaction

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