Fluoride-Promoted Oxidation of Fischer Alkoxy Carbene Complexes:  Stoichiometric and Catalytic Conditions

Barluenga, José; Andina, Facundo; Fernández‐Rodríguez, Manuel A.; García‐García, Patricia; Merino, Isabel; Aguilar, Enrique

doi:10.1021/jo048736s

Cited by 32 publications

(16 citation statements)

References 26 publications

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“…The oxidation appears to be a convenient method to convert Fischer alkoxy carbene complexes into the corresponding ester products [23]. Thus, different protocols are available to carry out this transformation [24][25][26]. However, when Fischer amine carbene complexes are used as starting material, harsh reaction conditions are usually required.…”

Section: Introductionmentioning

confidence: 99%

An expedient approach to ferrocenyl thioamides via Fischer carbenes

Sandoval-Chávez

López‐Cortés

Gutiérrez-Hernández

et al. 2009

Journal of Organometallic Chemistry

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Section: Introductionmentioning

confidence: 99%

An expedient approach to ferrocenyl thioamides via Fischer carbenes

Sandoval-Chávez

López‐Cortés

Gutiérrez-Hernández

et al. 2009

Journal of Organometallic Chemistry

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“…Formation of esters from FCCs usually requires an oxidant. [10][11][12][13][14][15][16][17][18] In our case, esters 5 were obtained from carbene complexes 2/O 2 along with the oxidative promoter NEt 3 in MeOH. The structure of compound 5 a-1 was also determined by a single-crystal X-ray diffraction analysis.…”

Section: Resultsmentioning

confidence: 99%

“…Barluenga and co-workers provided a new way for the formation of esters by fluoride-promoted oxidation of FCCs. [18] Aldehyde compounds are highly desirable because of the ease with which modifications to the functional group can be made. The Wacker process with ethylene and palladium complexes [19] and oxidation of alcohol by reagents, such as potassium dichromate [20] or pyridinium chlorochromate, are also commonly practiced.…”

Section: Introductionmentioning

confidence: 99%

Cyclization of Aromatic Propargyl Alcohol with a Thiophene Group Yielding Naphthothiophene Aldehyde Induced by a Ruthenium Complex

Tsai

Huang

et al. 2012

Chemistry A European J

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The reactions of [Cp(PPh(3))(2) RuCl] (Cp=cyclopentadienyl) with phenyl propargylic alcohol 1a, with a 3-thiophene group, are explored. The carbene complex 2a, obtained exclusively from this reaction at low temperature, contains the naphthothiophene group, which is formed through a new cyclization process between the thiophene group and the inner carbon of the triple bond. Details of this process have been revealed by conducting the reaction at room temperature, affording the allenylidene complex 3a as a side product. Complex 3a is not converted into 2a, indicating that the cyclization takes place while the triple bond is π coordinated to the metal center. Complex 2a reacts with oxygen in the presence of NEt(3) at room temperature to afford, in high yield, naphthothiophene aldehyde 4a, ONEt(3), OPPh(3), and [Cp(PPh(3))(2)RuCl]. Molecular O(2) is likely activated by coordination to the metal center when one of the phosphane ligands dissociates. Then, NEt(3) promotes the oxygenation process by reacting with the coordinated O(2) to afford ONEt(3) and possibly an unobserved oxo-carbene complex. Coupling of the oxo and carbene ligands then yields 4a and [Cp(PPh(3))(2) RuCl] in CHCl(3). In a solvent system containing MeOH, the oxygenation reaction affords a mixture of 4a and naphthothiophene ester 5a-1. The reactions of [Cp(dppf)RuCl] (dppf=1,1'-bis(diphenylphosphino)ferrocene) with 1a, also afford the carbene complex 2a', 4a, and 5a, which have been characterized by X-ray diffraction analyses. For the phenyl propargylic alcohol 1b, with a 2-thiophene substituent, different naphthothiophene aldehyde and ester compounds are also obtained in high yields through a similar cyclization process followed by oxygenation under mild conditions.

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“…The structure of pyranylidene carbene complex 23 was determined by NMR spectroscopic analysis. Moreover, the oxidation of FCC 23 to its analogous ester 24 by air, with tetrabutylammonium fluoride (TBAF) in DME, [21] allowed complete confirmation of the proposed structure (Scheme 6). Topologically, this transformation can be classified as a…”

Section: Introductionmentioning

confidence: 92%

Competitive Pathways in the Reaction of Lithium Oxy‐ortho‐quinodimethanes and Fischer Alkoxy Alkynyl Carbene Complexes: Synthesis of Highly Functionalised Seven‐Membered Benzocarbocycles

García‐García

Novillo

Fernández‐Rodríguez

et al. 2010

Chemistry A European J

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Up to four different outcomes have been found for the reaction between 1-oxy-ortho-quinodimethanes (oQDMs) and alkoxy alkynyl Fischer carbene complexes (FCCs). The product formed depends on the structure of both reagents and on the reaction solvent. The pathways can be topologically classified as a [4C+2C], a [3(2C+O)+3C], and two different [4C+3C] processes and, in all these sequences, 1-oxy-oQDMs behave as enolates or as vinylogous enolates. The reaction of Choy and Yang's unsubstituted oQDM 1 with tungsten alkynyl FCCs is solvent controlled; thus, selective formation of benzocycloheptenones can be achieved in THF, whereas exclusive synthesis of benzocycloheptene ketals is reached in diethyl ether. On the other hand, THF is the solvent of choice to form benzocycloheptene ketals when an alkyl or aryl group is placed at position 1 of the oQDM in its reaction with tungsten carbene complexes; however, a pyranylidene carbene complex is formed when a chromium carbene complex is used. Alternatively, the presence of bulky alkoxy groups in the FCC component favours a Diels-Alder aromatisation sequence, which leads to 1-naphthyl FCCs. Furthermore, the isolation and the characterisation of several deuterated compounds by labelling experiments have provided some insight into the reaction pathways, and mechanisms consistent with those findings have been established and several reaction intermediates have been identified.

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Fluoride-Promoted Oxidation of Fischer Alkoxy Carbene Complexes: Stoichiometric and Catalytic Conditions

Cited by 32 publications

References 26 publications

An expedient approach to ferrocenyl thioamides via Fischer carbenes

An expedient approach to ferrocenyl thioamides via Fischer carbenes

Cyclization of Aromatic Propargyl Alcohol with a Thiophene Group Yielding Naphthothiophene Aldehyde Induced by a Ruthenium Complex

Competitive Pathways in the Reaction of Lithium Oxy‐ortho‐quinodimethanes and Fischer Alkoxy Alkynyl Carbene Complexes: Synthesis of Highly Functionalised Seven‐Membered Benzocarbocycles

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