Gold-Catalyzed O–H Bond Addition to Unsaturated Organic Molecules

Huguet, Núria; Echavarren, Antonio M.

doi:10.1007/3418_2011_21

Cited by 29 publications

(13 citation statements)

References 235 publications

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“…electronic configuration; the C-Au-Br angles are in fact 173.5 (2) and 175.4(2). The Ccarbene-Au and Au-Br bond distances agree with the literature values for similar compounds [34].…”

supporting

confidence: 87%

“…Gold catalyzed hydroalkoxylation of alkynes, first reported in the late nineties [1], is an interesting 100% atom-economic reaction that allows for the preparation of vinyl ethers and acetals [2]. This reaction is conveniently catalyzed by cationic gold(I) complexes of general formula AuL + , usually prepared in situ, starting from the neutral species AuLX by halide abstraction with the silver AgY salt (Y = poorly coordinating anion) [3].…”

Section: Introductionmentioning

confidence: 99%

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Hydroalkoxylation of Terminal and Internal Alkynes Catalyzed by Dinuclear Gold(I) Complexes with Bridging Di(N-Heterocyclic Carbene) Ligands

et al. 2019

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A series of six dinuclear gold(I) complexes with bridging bidentate N-heterocycic carbene ligands (NHCs) of general formula Au2Br2LX (L = diNHC, X = 1–6) have been studied as catalysts in the intermolecular hydroalkoxylation of terminal and internal alkynes. The best catalytic results have been obtained by using Au2Br2L4, characterized by 2,6-diisopropylphenyl wingtip substituents and a methylene bridging group between the two NHC donors. Complex Au2Br2L4 has been structurally characterized for the first time in this work, showing the presence of intramolecular aurophiclic interaction in the solid state. In the adopted reaction conditions Au2Br2L4 is able to convert challenging substrates such as diphenylacetylene. Comparative catalytic tests by using the mononuclear gold(I) complexes AuIL7 and IPrAuCl have been performed in order to determine the possible presence of cooperative effects in the catalytic process.

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“…electronic configuration; the C-Au-Br angles are in fact 173.5 (2) and 175.4(2). The Ccarbene-Au and Au-Br bond distances agree with the literature values for similar compounds [34].…”

supporting

confidence: 87%

Section: Introductionmentioning

confidence: 99%

Hydroalkoxylation of Terminal and Internal Alkynes Catalyzed by Dinuclear Gold(I) Complexes with Bridging Di(N-Heterocyclic Carbene) Ligands

et al. 2019

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“…17 Over the past two decades, this gold-catalyzed variant has been well explored. 25 Recently, several experimental studies have been performed to gain insight into the mechanism of this transformation 26 as well as to determine the effect of a silver salt 27 and its counterion 28 when employed in gold-catalyzed additions to alkynes. In general, addition to terminal alkynes occurs at the internal carbon to give the corresponding ketal 29 or enol ether 30 products (Fig.…”

Section: Introductionmentioning

confidence: 99%

Regioselectivity in the Au-catalyzed hydration and hydroalkoxylation of alkynes

2015

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Over the past decade and a half, homogenous gold catalysis has emerged as a diverse and rich field of research resulting in the continuous development of new methods for organic synthesis. The activation of alkynes towards nucleophilic attack by Au(I) and Au(III) complexes is a well-established mode of reactivity and the gold-catalyzed hydration and hydroalkoxylation of alkynes are two of the more well-explored reaction pathways. Although these classes of reactions have seen continuous development since their initial reports, achieving regioselectivity persists as one of the most challenging issues for this chemistry. This article aims to draw attention to the general problem of regioselectivity in these reactions. A select set of examples is presented to highlight the challenges and survey some of the strategies employed to address this problem.

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“…The reactivity between a nonpolar reactant (unsaturated C–C bond) and a highly polar molecule (water) is not favorable; thus, the presence of a catalyst is required for these processes to proceed. There have been several metals employed as catalysts (Rh, Pd, Pt, Ru, others), but gold occupies a prominent place due to its ability to activate C–C unsaturated bonds for addition reactions. , Hence, gold-catalyzed additions of O-based nucleophiles have been largely explored . The use of the simplest O-based nucleophile, water, is commonly found for alkynes but is much less common for alkenes and allenes.…”

Section: Introductionmentioning

confidence: 99%

Comparative Mechanistic Study on the [Au(NHC)]⁺-Catalyzed Hydration of Alkynes, Alkenes, and Allenes

et al. 2020

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The addition of water molecules to unsaturated substrates is a highly desirable process. Additions to alkynes are very common, whereas additions to allenes and specially alkenes are rather scarce. One of the main aims here is to perform a comparative analysis of their reaction mechanisms for the process catalyzed by Au(I); another objective is to analyze why alkenes are much less reactive than their alkyne or allene counterparts. With this purpose the reaction mechanism for the addition of water to terminal and internal alkynes, alkenes, and allenes catalyzed by an [Au(NHC)] + complex (NHC = N-heterocyclic carbene) is analyzed by means of DFT calculations. The general catalytic cycle for the three kinds of substrates can be described by three main steps: (i) reactant π coordination to the Au(I) complex, (ii) water nucleophilic addition, and (iii) protodeauration, with subtle differences among the reactants. A comparative analysis, from the evolution of the centroids of localized molecular orbitals (CLMO), of the electronic rearrangements taking place in the protodeauration step reveals different mechanisms for these three substrates, both regarding the electron pair that accepts the proton and the fate of the Au−C bond pair. For alkenes calculations show that nucleophilic addition is highly demanding but affordable, whereas protodeauration is in any case energetically prohibitive. The main reason is not the intrinsic barrier of the protodeauration step, just a few kcal mol −1 higher than that of alkynes, but the high energy of the water-added intermediate. This issue is not related to the strength of the Au(I)−CC bond but to that of the C−O bond.

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Gold-Catalyzed O–H Bond Addition to Unsaturated Organic Molecules

Cited by 29 publications

References 235 publications

Hydroalkoxylation of Terminal and Internal Alkynes Catalyzed by Dinuclear Gold(I) Complexes with Bridging Di(N-Heterocyclic Carbene) Ligands

Hydroalkoxylation of Terminal and Internal Alkynes Catalyzed by Dinuclear Gold(I) Complexes with Bridging Di(N-Heterocyclic Carbene) Ligands

Regioselectivity in the Au-catalyzed hydration and hydroalkoxylation of alkynes

Comparative Mechanistic Study on the [Au(NHC)]⁺-Catalyzed Hydration of Alkynes, Alkenes, and Allenes

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Gold-Catalyzed O–H Bond Addition to Unsaturated Organic Molecules

Cited by 29 publications

References 235 publications

Hydroalkoxylation of Terminal and Internal Alkynes Catalyzed by Dinuclear Gold(I) Complexes with Bridging Di(N-Heterocyclic Carbene) Ligands

Hydroalkoxylation of Terminal and Internal Alkynes Catalyzed by Dinuclear Gold(I) Complexes with Bridging Di(N-Heterocyclic Carbene) Ligands

Regioselectivity in the Au-catalyzed hydration and hydroalkoxylation of alkynes

Comparative Mechanistic Study on the [Au(NHC)]+-Catalyzed Hydration of Alkynes, Alkenes, and Allenes

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Comparative Mechanistic Study on the [Au(NHC)]⁺-Catalyzed Hydration of Alkynes, Alkenes, and Allenes