Efficient Gold‐Catalyzed Hydroamination of 1,3‐Dienes

Brouwer, Chad; He, Chuan

doi:10.1002/ange.200504495

Cited by 70 publications

(14 citation statements)

References 41 publications

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“…It should be mentioned that after deprotection of the nitrogen, substrate 11 could be converted to product 6k under the standard reaction conditions of the gold catalysis (Scheme 6). Nevertheless, the reaction rates for the hydroamination of the 1,3-diene [26] 11 turned out to be much slower than for the cycloisomerization of the corresponding allene 5k (incomplete conversion after 72 h instead of complete conversion after 1 h for the allene). This indicates that the stepwise sequence is only a minor alternative pathway that leads to the same final product.…”

Section: Resultsmentioning

confidence: 96%

On the Gold‐Catalyzed Intramolecular 7‐exo‐trig Hydroamination of Allenes

et al. 2013

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Aniline derivatives with allene side tethers were tested as substrates for a gold-catalyzed 7-exotrig hydroamination reaction. The nucleophilicity of the aniline derivatives plays an important role for the outcome of the reaction. While electron-deficient protecting groups at the nitrogen led to competing pathways like hydroarylation or an allene to diene isomerization, clean formation of the desired benzoxazepines was obtained with unprotected aniline derivatives.Chemicals were purchased from commercial suppliers and used without further purification. Dry solvents were dispensed from the solvent purification system MB SPS-800. NMR spectra were, if not mentioned otherwise, recorded at room temperature on the following spectrometers: Bruker ARX-250, Bruker Avance DRX-300, Bruker Avance III-Scheme 7. Summary of the possible pathways for anilines 5 or 8.

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Section: Resultsmentioning

confidence: 96%

On the Gold‐Catalyzed Intramolecular 7‐exo‐trig Hydroamination of Allenes

et al. 2013

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“…[1] Recently, in-depth kinetic and mechanistic studies on the gold(I)catalyzed nucleophilic addition to a carbonÀcarbon unsaturated bond have been published, with the aim to understand the ligand effect [2] and to isolate and characterize the intermediates involved in the catalytic cycle. [3, 4] However, also the anion can influence the catalytic activity, [5] the regioselectivity, [6] and even the stereoselectivity [7] of the process. Moreover, it has been observed that the anion can influence the structure of the catalyst [8] and of the intermediates in the catalytic cycle.…”

mentioning

confidence: 99%

Unexpected Anion Effect in the Alkoxylation of Alkynes Catalyzed by N‐Heterocyclic Carbene (NHC) Cationic Gold Complexes

Biasiolo

Trinchillo

Belanzoni

et al. 2014

Chemistry A European J

133

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The intermolecular alkoxylation of alkynes is the oldest application of cationic gold(I) catalysts; however, no systematic experimental data about the role of the anion are available. In this contribution, the role of the anion in this catalytic reaction as promoted by a N-heterocyclic carbene-based gold catalyst, [(NHC)AuX] (X=BARF(-) , BF4 (-) , OTf(-) , OTs(-) , TFA(-) , or OAc(-) ) is analyzed, through a combined experimental (NMR spectroscopy) and theoretical (DFT calculation) approach. The most important factor seems to be the ability to abstract the proton from the methanol during the nucleophilic attack, and such ability is related to the anion basicity. On the other hand, too high coordination power or basicity of the anion worsens the catalytic performance by preventing alkyne coordination or by forming too much free methoxide in solution, which poisons the catalyst. The intermediate coordinating power and basicity of the OTs(-) anion provides the best compromise to achieve efficient catalysis.

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“…In practice, the vast majority of reported diene hydroamination reactions are selective for the formation of allylic amines. [3] In particular, known hydroamination reactions catalyzed by nickel or palladium give exclusively allylic amines, owing to the intermediacy of an h 3 -allyl complex. [4] Similarly, Brønsted acid catalyzed hydroamination reactions also generate allylic amines, as predicted by the stability of the intermediate allyl cation.…”

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confidence: 99%

Palladium(II)‐Catalyzed Intramolecular Hydroamination of 1,3‐Dienes to Give Homoallylic Amines

Pierson

Ingalls

et al. 2013

Angew Chem Int Ed

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A pincer for high selectivity: A mild palladium‐catalyzed hydroamination of protected amino‐1,3‐dienes is possible. This highly regioselective reaction employs a tridentate PNP pincer ligand and leads to cyclic and homoallylic protected amines in high yields. Substrates with a wide array of amine protecting groups and diene substitution patterns were cyclized to form five‐ and six‐membered heterocycles. PG=protecting group.

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Efficient Gold‐Catalyzed Hydroamination of 1,3‐Dienes

Cited by 70 publications

References 41 publications

On the Gold‐Catalyzed Intramolecular 7‐exo‐trig Hydroamination of Allenes

On the Gold‐Catalyzed Intramolecular 7‐exo‐trig Hydroamination of Allenes

Unexpected Anion Effect in the Alkoxylation of Alkynes Catalyzed by N‐Heterocyclic Carbene (NHC) Cationic Gold Complexes

Palladium(II)‐Catalyzed Intramolecular Hydroamination of 1,3‐Dienes to Give Homoallylic Amines

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