Organische Synthesen mit übergangsmetallkomplexen, 211) 1‐Chroma‐1,3‐butadiene und 1‐Chroma‐1,3,5‐hexatriene aus (CO)5CrC(OC2H5)CH3 durch Carbonyl‐Olefinierung mit Triethylamin/Chlortrimethylsilan

Aumann, Rudolf; Heinen, Heinrich

doi:10.1002/cber.19871200413

Cited by 155 publications

(65 citation statements)

References 12 publications

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“…[7] The [alkenyl(-methoxy)carbene]tungsten complex 2c, containing a pphenylaldehyde group, was generated in a 40% yield on activation of the propargyl alcohol derivative c with W(CO) 5 (THF). Subsequent addition of dimethylamine afforded, almost quantitatively, the corresponding (dimethylamino)carbene complex 1c (Scheme 5).…”

Section: Synthesis Of Bis(carbene)-bridged Tungsten؊chromium Complexesmentioning

confidence: 99%

“…Thus, symmetrical bis(carbene) complexes of Groups 6 and 7 metals containing aryl [3,4] and thienyl [5,6] bridges are accessible from dilithiated aromatic precursors by the classic Fischer method. A series of alkenyl-or polyenyl-bridged bis(carbene) complexes have been prepared either by condensation reactions of dialdehydes with the methyl group of (alkoxy)methylcarbene complexes, [7,8,9] or by oxidative coupling of [M]ϭ C(OR)CH 2 Li. [10,11] The synthesis of a symmetrical bis(carbene) complex with an ammonium pentadienide bridge has also been described.…”

Section: Introductionmentioning

confidence: 99%

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Symmetric and Non-Symmetric Dinuclear Alkenyl-Bridged Carbene Complexes of Chromium and Tungsten

Ulrich

Guerchais

Dötz

et al. 2001

Eur. J. Inorg. Chem.

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Treatment of (CO)5W=C(NMe2)CH=CH−Ar−(OH)(H)C≡CH (1a−b) [a: −Ar− =1,4‐C6H4−; b: −Ar− = 2,5‐C4H2S−] with W(CO)5(THF) in methanol yields the nonsymmetrical bis(alkenylcarbene)‐bridged ditungsten complexes (CO)5W=C(NMe2)CH=CH−Ar−CH=CH(OMe)C=W(CO)5 (3a−b). Similarly, the symmetrical bis(methoxycarbene)ditungsten derivative [(CO)5W=C(OMe)CH=CH−]2(1,4‐C6H4−) (4a) is obtained in a low yield from the precursor (CO)5W=C(OMe)CH=CH−C6H4−(OH)(H)C≡CH (2a). Complexes 3a and 3b undergo aminolysis reactions with diamines such as piperazine and ethylenediamine to produce the corresponding bis[alkenyl(amino)carbene]ditungsten complexes 5a−b and 6a−b. The reaction of 1a with Cr(CO)5(THF) affords the heterobimetallic (W−Cr) bis(carbene) complex (CO)5W=C(NMe2)CH=CH−Ar−CH=CH(OMe)C=Cr(CO)5 (3′a). This complex, as well as the bis(methoxycarbene) derivative 4′a, can also be obtained by treatment of (CO)5W=C(XR)CH=CH−C6H4−CHO [1c: XR = NMe2; 2c: XR = OMe] with (CO)5Cr=C(OMe)CH2−Li+. All the new compounds have been characterized by analytical and spectroscopic methods, and the single‐crystal structures of 3a, 4a−b, and 4′a have been established.

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Section: Synthesis Of Bis(carbene)-bridged Tungsten؊chromium Complexesmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Symmetric and Non-Symmetric Dinuclear Alkenyl-Bridged Carbene Complexes of Chromium and Tungsten

Ulrich

Guerchais

Dötz

et al. 2001

Eur. J. Inorg. Chem.

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“…tained following the Aumann procedure, [19] by reaction of pentacarbonylA C H T U N G T R E N N U N G (ethoxy)methylchromium(0) carbene (15) [18] and aldehyde 14 [20] (Scheme 4).…”

Section: Resultsmentioning

confidence: 99%

The Electronic Structure and Photochemistry of Group 6 Bimetallic (Fischer) Carbene Complexes: Beyond the Photocarbonylation Reaction

Lage

Fernández

Mancheño

et al. 2010

Chemistry A European J

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The UV spectra of Group 6 metal carbene complexes bearing a CpM(CO)(3) (Cp = cyclopentadienyl) moiety bonded to the carbene carbon atom exhibit a redshift of the absorption maxima at higher wavelengths with respect to the parent monometallic complexes. This redshift is partly due to a higher occupation on the p(z) atomic orbital of the carbene carbon atom. Time-dependent DFT calculations accurately assign this band to a metal-to-ligand charge-transfer transition, thus showing that the presence of a second metal center does not affect the nature of the transition. However, the photochemical reactivity of Group 6 metal carbene complexes bearing a CpM(CO)(3) moiety strongly depends on the nature of this metal fragment. A new photoslippage reaction leading to fulvenes occurs when Mn-derived products 11 a, 11 b, and 12 a are irradiated (both Cr and W derivatives), whereas Re-derived product 11 c behaves like standard Fischer complexes and yields the usual photocarbonylation products. A new photoreduction process occurring in the metallacyclopropanone intermediate is also observed for these complexes. Both computational and deuteration experiments support this unprecedented photoslippage process. The key to this differential photoreactivity seems to be the M-Cp back-donation, which hampers the slippage process for Re derivatives and favors the carbonylation reaction.

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“…Materials: Carbene complexes 1 a,b, [18] 1 c, [19] 5, [20] 7, [21] 10 a, [22] and 10 b,c [23] were prepared according to literature procedures. 1-Amino-1,3-dienes were prepared according to the following procedure: The corresponding aldehyde (crotonaldehyde, 3-methyl-2-butenal, or trans-2-methyl-2-butenal; 10 mmol) was added to a solution of LDA, prepared from diisopropylamine (12.5 mmol) and BuLi (12.5 mmol, 1.6 m hexane solution) in THF (10 mL) at 0 8C under an argon atmosphere and the mixture was stirred 5 min.…”

Section: Methodsmentioning

confidence: 99%

Diastereoselective Synthesis of Three‐, Five‐, Six‐, and Seven‐Membered Rings from Fischer Carbene Complexes and 4‐Unsubstituted 1‐Amino‐1,3‐Dienes

Aznar

Fañanás‐Mastral

Alonso

et al. 2007

Chemistry A European J

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Fischer carbene complexes react with 4-unsubstituted 1-amino-1,3-dienes to give different carbocyclization products depending on the nature of the carbene complex and on the substitution pattern of the aminodiene. Thus, the reaction of arylcarbene chromium complexes and 1-aminodienes diastereoselectively affords cyclopropane derivatives by means of a formal [2+1] carbocyclization reaction. In particular, pentacarbonyl[(2-furyl)(methoxy)methylene]chromium complex furnishes formal [4+1] carbocyclization products. Starting from beta-substituted alkenylcarbene complexes, formal [4+1] reactions occur and cyclopentenamine derivatives are diastereoselectively formed. However, when the alpha,beta-disubstituted alkenylcarbene complex pentacarbonyl[(5,6-dihydro-2H-pyran-2-yl)(methoxy)methylene]tungsten is used, the outcome of the reaction depends on the substitution on the carbon atom at the 3-position of the aminodiene, generating the [3+2] or [4+3]-cyclization products if the substituent is or is not a hydrogen atom, respectively. Finally, when the reaction is performed with alkynylcarbene complexes, benzaldehyde derivatives are obtained if the triple-bond substituent is a phenyl group or indene derivatives if the group is an alkenyl moiety.

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Organische Synthesen mit übergangsmetallkomplexen, 21¹⁾ 1‐Chroma‐1,3‐butadiene und 1‐Chroma‐1,3,5‐hexatriene aus (CO)₅CrC(OC₂H₅)CH₃ durch Carbonyl‐Olefinierung mit Triethylamin/Chlortrimethylsilan

Cited by 155 publications

References 12 publications

Symmetric and Non-Symmetric Dinuclear Alkenyl-Bridged Carbene Complexes of Chromium and Tungsten

Symmetric and Non-Symmetric Dinuclear Alkenyl-Bridged Carbene Complexes of Chromium and Tungsten

The Electronic Structure and Photochemistry of Group 6 Bimetallic (Fischer) Carbene Complexes: Beyond the Photocarbonylation Reaction

Diastereoselective Synthesis of Three‐, Five‐, Six‐, and Seven‐Membered Rings from Fischer Carbene Complexes and 4‐Unsubstituted 1‐Amino‐1,3‐Dienes

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