Keteniminkomplexe aus Carbenkomplexen und Isocyaniden – vielseitige Bausteine für Carbocyclen und N‐Heterocyclen

Aumann, Rudolf

doi:10.1002/ange.19881001106

Cited by 81 publications

(11 citation statements)

References 79 publications

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“…In particular, metal-assisted synthesis of ketenimines can be accomplished either by coupling of metal carbenes with isocyanides or from metal isocyanides and diazo compounds acting as carbene sources . Furthermore, in a number of cases ketenimine groups have been generated by isocyanide addition, insertion, multiple insertion, or coupling with a variety of different ligands and metal complexes, through rather unpredictable reactions …”

Section: Resultsmentioning

confidence: 99%

Addition of Isocyanides at Diiron μ-Vinyliminium Complexes: Synthesis of Novel Ketenimine−Bis(alkylidene) Complexes

et al. 2008

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Reactions of the vinyliminium complexes [Fe2{μ-η1:η3-Cγ(R′)Cβ(H)CαN(Me)(R)}(μ-CO)(CO)(Cp)2][SO3CF3] (R = Xyl, R′ = Me, 1a; R = Xyl, R′ = CO2Me, 1b; R = 4-C6H4OMe, R′ = CO2Me, 1c; Xyl = 2,6-Me2C6H3) with isocyanides (CNR′′), in the presence of NaH, lead to abstraction of the Cβ−H proton and to isocyanide addition with formation of a carbon−carbon double bond. The observed products are the ketenimine−bis(alkylidene) complexes [Fe2{μ-η1:η2-Cγ(R′)Cβ(CNR′′)CαN(Me)(R)}(μ-CO)(CO)(Cp)2] (R = Xyl, R′ = Me, R′′ = Xyl, 2a; R = Xyl, R′ = CO2Me, R′′ = Xyl, 2b; R = Xyl, R′ = CO2Me, R′′ = But, 2c; R = Xyl, R′ = CO2Me, R′′ = 4-C6H4CN, 2d; R = 4-C6H4OMe, R′ = CO2Me, R′′ = But, 2e), obtained in 60−70% yields. Conversely, the vinyliminium complex [Fe2{μ-η1:η3-Cγ(CO2Me)Cβ(H)CαN(Me)2}(μ-CO)(CO)(Cp)2][SO3CF3] (1d) undergoes double isocyanide addition. Reactions of 1d with a 2-fold excess of CNXyl or CNBut, in the presence of NaH, afford [Fe(CO)(Cp)Cα(NMe2)Cβ(CNXyl)Cγ(CO2Me)C(NXy)Fe(CO)(Cp)] (3) and [Fe(CO)(Cp)C(NBut)Cα(NMe2)CβCγ(CO2Me)Fe(Cp)(CO)CNBut] (4), respectively. Finally, the vinyliminium complex [Fe2{μ-η1:η3-Cγ(H)Cβ(H)CαN(Me)2}(μ-CO)(CO)(Cp)2][SO3CF3] (1e), treated with with CNBut and NaH, yields a mixture of the diiron aminocarbyne complexes [Fe2{μ-CN(Me)2}(μ-CO)(CO)(Cp)(C5H5CH2CN)(CNBut)], (6) and [Fe2{μ-CN(Me)2}(μ-CO)(CO)(Cp)2(CNBut)] (5). The molecular structures of 2a,b, 3·1.5CH2Cl2, 4, and 6·0.5Et2O have been ascertained by X-ray diffraction studies.

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Section: Resultsmentioning

confidence: 99%

Addition of Isocyanides at Diiron μ-Vinyliminium Complexes: Synthesis of Novel Ketenimine−Bis(alkylidene) Complexes

et al. 2008

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“…1-Metalla-2,4-dioxy-1,3-butadienes. 1-Metalla-1,3-butadienes 2 (=alkenylcarbene complexes) of chromium and tungsten have gained much interest as C 3 building blocks for the synthesis of carbocyclic and heterocyclic ring compounds. , Among the broad array of 1-metalla-1,3-dienes the 2,4-dioxy derivatives (CO) 5 MC(OEt)CHCR(OR 1 ) (M = Cr, W) deserve special attention with regard to the structural relationship to 1,3-dicarbonyl equivalents and the synthethic implications based on such a relationship. 1-Metalla-1,3-butadienes have been prepared as early as 1967, but systematic studies were initiated only recently.…”

mentioning

confidence: 99%

“…Ligand disengagement from Fischer carbene complexes can be most easily achieved by addition of isocyanides. The key step of this reaction involves insertion of the isocyano function into the MC bond of the carbene complex, which leads to production of a ketenimine complex 4b. Addition of cyclohexyl isocyanide ( 17 ) to the 1-chroma-1,3-diene ( E )- 10b seems to follow this general route to a ketenimine complex ( E )- 20 .…”

mentioning

confidence: 99%

Organic Syntheses via Transition Metal Complexes. 85.¹ [2-(Alkenyloxy)ethenyl]- and [2-(Aryloxy)ethenyl]carbene Complexes from (1-Alkynyl)carbene Complexes of Chromium and Tungsten and Their Fragmentation to 2,4-Dien-5-ones

1996

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[2-(Alkenyloxy)ethenyl]carbene complexes (CO)5MC(OEt)CHC(O-alkenyl)Ph (3) (M = Cr, W) are obtained by base-catalyzed O-addition of enolizable 1,3-diones 2 (cyclopentane-1,3-dione and dimedone) to (1-alkynyl)carbene complexes (CO)5MC(OEt)C⋮CPh (1) (M = Cr, W) together with pyran-2-ylidene complexes 4, which are generated by C-addition of the enolate unit of 2. Thermal fragmentation of the O-addition products 3 affords dienones 5, resulting from overall C3 insertion of the (1-alkynyl)carbene ligand of 1 into a C,O bond of 2. Both, O- and C-addition products, 7 and 8, respectively, are derived from reaction of 9-phenanthrol (6) with 1 in a ratio 2:1, but phenol (9a) and 2-naphthol (9b) yield [2-(aryloxy)ethenyl]carbene complexes (CO)5MC(OEt)CHC(OAr)Ph (10) (M = Cr, W; Ar = Ph, 2-naphthyl) only (81−91%). Addition of 9 is highly regio- and stereoselective and affords stereoisomers (E)-10 initially, which undergo (E/Z) isomerization in solution to give isomers (Z)-10. Binuclear carbene complexes 12, 14, and 16 [(CO)5MC(OEt)CHC(Ph)OArO(Ph)CCH(OEt)CM(CO)5 (M = Cr, W)] are obtained from dihydroxyaryl compounds Ar(OH)2 (Ar = 1,4-phenylene, 1,3-phenylene, 1,1‘-binaphthyl). Addition of cyclohexyl isocyanide (17) to (Z)-10 results in formation of a ketenmine complex (CO)5Cr[CyNCC(OEt)CHC(OPh)Ph], which in the presence of water and (excess) 17 affords an (1-amino)ketocarbene complex (CO)5CrC(NHCy)C(O)CHC(OPh)Ph (18) and an amide (CyNH)C(O)CH(OEt)CHC(OPh)Ph (19). X-ray data are reported for compounds (Z)-3b, (E)-10d, and (E,E)-12a.

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“…Isocyanides also react with carbene complexes, giving rise to ketenimine intermediates that evolve to form various types of organic products depending on the substitution pattern of the starting carbenes 4. More specifically, when an alkoxy alkenyl complex bearing an additional double bond is used, o ‐alkoxyanilines are obtained from the electrocyclic ring‐closure of the initially formed ketenimine intermediate (Scheme ) 5.…”

Section: Introductionmentioning

confidence: 99%

Efficient Synthesis of Highly Functionalized Indazoles and 2,3-Dihydro-1,2-benzisoxazoles by Reaction of Stable Fischer Dienyl Carbenes and Isocyanides

2001

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A range of stable chromium and tungsten Fischer dienyl carbenes have been prepared by [3+2] cycloaddition of alkenylethynyl carbene complexes with nitrones or diazoalkanes. Treatment of these systems with isocyanides gives entry to highly functionalized 2,3-dihydro-1,2-benzisoxazoles and indazoles in a completely regioselective fashion, under mild conditions, and with high yields. This methodology can be also applied to the preparation of analogous naphthoisoxazoles starting from arylethynyl Fischer complexes. Reductive cleavage of the isoxazole moiety in the prepared heterocycles also enables the efficient synthesis of highly substituted p-aminophenols.

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Keteniminkomplexe aus Carbenkomplexen und Isocyaniden – vielseitige Bausteine für Carbocyclen und N‐Heterocyclen

Cited by 81 publications

References 79 publications

Addition of Isocyanides at Diiron μ-Vinyliminium Complexes: Synthesis of Novel Ketenimine−Bis(alkylidene) Complexes

Addition of Isocyanides at Diiron μ-Vinyliminium Complexes: Synthesis of Novel Ketenimine−Bis(alkylidene) Complexes

Organic Syntheses via Transition Metal Complexes. 85.¹ [2-(Alkenyloxy)ethenyl]- and [2-(Aryloxy)ethenyl]carbene Complexes from (1-Alkynyl)carbene Complexes of Chromium and Tungsten and Their Fragmentation to 2,4-Dien-5-ones

Efficient Synthesis of Highly Functionalized Indazoles and 2,3-Dihydro-1,2-benzisoxazoles by Reaction of Stable Fischer Dienyl Carbenes and Isocyanides

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Keteniminkomplexe aus Carbenkomplexen und Isocyaniden – vielseitige Bausteine für Carbocyclen und N‐Heterocyclen

Cited by 81 publications

References 79 publications

Addition of Isocyanides at Diiron μ-Vinyliminium Complexes: Synthesis of Novel Ketenimine−Bis(alkylidene) Complexes

Addition of Isocyanides at Diiron μ-Vinyliminium Complexes: Synthesis of Novel Ketenimine−Bis(alkylidene) Complexes

Organic Syntheses via Transition Metal Complexes. 85.1 [2-(Alkenyloxy)ethenyl]- and [2-(Aryloxy)ethenyl]carbene Complexes from (1-Alkynyl)carbene Complexes of Chromium and Tungsten and Their Fragmentation to 2,4-Dien-5-ones

Efficient Synthesis of Highly Functionalized Indazoles and 2,3-Dihydro-1,2-benzisoxazoles by Reaction of Stable Fischer Dienyl Carbenes and Isocyanides

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Organic Syntheses via Transition Metal Complexes. 85.¹ [2-(Alkenyloxy)ethenyl]- and [2-(Aryloxy)ethenyl]carbene Complexes from (1-Alkynyl)carbene Complexes of Chromium and Tungsten and Their Fragmentation to 2,4-Dien-5-ones