C:O and C:C bond activation in diphenylketene promoted by dicarbonylbis(.eta.-cyclopentadienyl)titanium(II)

Fachinetti, Giuseppe; Biran, C.; Floriani, Carlo; Villa, A. Chiesi; Guastini, Carlo

doi:10.1021/ic50189a006

Cited by 56 publications

(14 citation statements)

References 41 publications

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“…The η 2 -ketone complex 25 has been subjected to single crystal X-ray diffraction analysis (Figure , Table ). Although a large number of aldehyde and ketone derivatives of the group 4 metals are known, they are typically bimolecular with bridging ketonic functions . There are, however, mononuclear ketene species which are directly related to 25 .…”

Section: Resultsmentioning

confidence: 99%

Synthesis and Chemistry of Titanacyclopentane and Titanacyclopropane Rings Supported by Aryloxide Ligation

et al. 1997

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Treatment of the titanacyclopentadiene compound [Ti(OC6H3Ph2-2,6)2(C4Et4)] (3) (OC6H3Ph2-2,6 = 2,6-diphenylphenoxide) with olefins leads to the formation of a variety of stable titanacyclopentane derivatives along with one equivalent of substituted 1,3-cyclohexadiene. The structural and spectroscopic properties of the ethylene product [Ti(OC6H3Ph2-2,6)2(CH2)4] (4) show a ground state titanacyclopentane structure, but facile fragmentation on the NMR time scale to form a bis(ethylene) complex has been detected. The substituted products [Ti(OC6H3Ph2-2,6)2(C4H6R2)] (R = Me, 5; Et, 6; Ph, 7) formed from α-olefins RCHCH2 exist as a mixture of regio- and stereoisomers in hydrocarbon solution. Analysis of a crystal obtained from solutions of 7 showed a trans-2,5-diphenyl-titanacyclopentane ring to be present in the solid state. Alternative routes to the titanacyclopentane compounds involve treatment of the dichlorides [Ti(OC6H3Ph2-2,6)2Cl2] (1) or [Ti(OC6HPh4-2,3,5,6)2Cl2] (2) with either sodium amalgam (2 Na per Ti) or 2 equiv of BunLi in the presence of the substrate olefin. Using these conditions the titanabicyclic compounds [(ArO)2Ti{CH2CH(C4H8)CHCH2}] (ArO = OC6H3Ph2-2,6, 10; OC6HPh4-2,3,5,6, 11) can be obtained by intramolecular coupling of 1,7-octadiene. The spectroscopic properties of 10 and 11 as well as a single-crystal X-ray diffraction analysis of 11 show an exclusive trans stereochemistry is present. Thermolysis of 10 or 11 in the presence of excess 1,7-octadiene leads to the catalytic formation of 2-(methylmethylene)cyclohexane (80%) along with E,Z isomers of 2,6-octadiene (20%). A kinetic study shows the reaction to be zero order in diene with activation parameters, ΔH ⧧ = +18.7(5) kcal mol-1 and ΔS ⧧ = −26(5) eu. The diphenyltitanacyclopentane 7 will catalyze the dimerization of styrene to trans-1,3-diphenylbut-1-ene followed by isomerization to 1,3-diphenylbut-2-ene. This result shows that although a 2,5-diphenyl regiochemistry was observed in the solid state, styrene dimerization occurs via the 2,4-diphenyltitanacyclopentane intermediate. The facile fragmentation of these titanacyclopentane compounds accounts for the products observed in a number of reactions. Addition of phosphine donor ligands (L) leads to a series of titanacyclopropane compounds [Ti(OC6H3Ph2-2,6)2(η2-CHRCH2)(L)] (R = H, 14; Me, 15; Et, 16; Ph, 17) along with 1 equiv of olefin. The solid-state structure of the ethylene complex 14 shows the C2H4 unit lies approximately coplanar with the Ti−PMe3 bond. This structure is not only maintained in solution but slow olefin rotation is observed on the NMR time scale. In the case of the α-olefin products, two isomers are detected by 1H, 13C, and 31P NMR spectroscopy. Addition of Ph2CO or PhCHNR (R = Ph, CH2Ph) to the titanacyclopentane and titanacyclopropane compounds leads to different products depending upon the reagent and reaction conditions. These can be classified as 2-oxa(aza)titanacycloheptanes, 2-oxa(aza)titanacyclopentanes, 2,5-dioxa(diaza)titanacyclopentanes, and examples of 2-oxa...

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Section: Resultsmentioning

confidence: 99%

Synthesis and Chemistry of Titanacyclopentane and Titanacyclopropane Rings Supported by Aryloxide Ligation

et al. 1997

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“…Such a dimer has been proposed as an intermediate leading to the reductive disproportionation of C02 and C02-like molecules. 29 Complex 1 reacted with DPK in a 1:1 molar ratio, forming 6 in very good yield: solvent molecules around Na omitted separated into the two components as reported in the Experimental Section.…”

Section: Resultsmentioning

confidence: 83%

How a bifunctional complex drives reactivity of carbon dioxide-like molecules: sodium [N,N'-ethylenebis(salicylaldiminato)]cobaltate(I) promotion of the reductive coupling of molecules resembling carbon dioxide

Arena¹,

Floriani²,

Chiesi‐Villa³

et al. 1986

Inorg. Chem.

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“…Crystal data for (2): Cl7HZ0N20,Ru2; M = 566.49, monoclinic, space group P2,/a, a = 13.4462 (8) The i.r. spectra of e.g.…”

Section: Imentioning

confidence: 99%

“…), 2.200(6); C(ll)-C(l2), 1.438(9); C(lO)-C(l l), 1.535(8); C(9)-C(10), 1.492(8); N(2)-C(9), 1.477(8); N…”

unclassified

Formation of a N–C bond between co-ordinated α-di-imine and a novel diketene fragment; X-ray crystal structure of {Ru₂(CO)₅[PrⁱNC(H)(H)C–N(Prⁱ)C(O)CH₂C(O)CH₂]}containing an η³-aza-allyl to Ru bonded moiety

Polm¹,

Koten²,

Vrieze³

et al. 1983

J. Chem. Soc., Chem. Commun.

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C:O and C:C bond activation in diphenylketene promoted by dicarbonylbis(.eta.-cyclopentadienyl)titanium(II)

Cited by 56 publications

References 41 publications

Synthesis and Chemistry of Titanacyclopentane and Titanacyclopropane Rings Supported by Aryloxide Ligation

Synthesis and Chemistry of Titanacyclopentane and Titanacyclopropane Rings Supported by Aryloxide Ligation

How a bifunctional complex drives reactivity of carbon dioxide-like molecules: sodium [N,N'-ethylenebis(salicylaldiminato)]cobaltate(I) promotion of the reductive coupling of molecules resembling carbon dioxide

Formation of a N–C bond between co-ordinated α-di-imine and a novel diketene fragment; X-ray crystal structure of {Ru₂(CO)₅[PrⁱNC(H)(H)C–N(Prⁱ)C(O)CH₂C(O)CH₂]}containing an η³-aza-allyl to Ru bonded moiety

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C:O and C:C bond activation in diphenylketene promoted by dicarbonylbis(.eta.-cyclopentadienyl)titanium(II)

Cited by 56 publications

References 41 publications

Synthesis and Chemistry of Titanacyclopentane and Titanacyclopropane Rings Supported by Aryloxide Ligation

Synthesis and Chemistry of Titanacyclopentane and Titanacyclopropane Rings Supported by Aryloxide Ligation

How a bifunctional complex drives reactivity of carbon dioxide-like molecules: sodium [N,N'-ethylenebis(salicylaldiminato)]cobaltate(I) promotion of the reductive coupling of molecules resembling carbon dioxide

Formation of a N–C bond between co-ordinated α-di-imine and a novel diketene fragment; X-ray crystal structure of {Ru2(CO)5[PriNC(H)(H)C–N(Pri)C(O)CH2C(O)CH2]}containing an η3-aza-allyl to Ru bonded moiety

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Formation of a N–C bond between co-ordinated α-di-imine and a novel diketene fragment; X-ray crystal structure of {Ru₂(CO)₅[PrⁱNC(H)(H)C–N(Prⁱ)C(O)CH₂C(O)CH₂]}containing an η³-aza-allyl to Ru bonded moiety