Anti-Addition Mechanism in the Intramolecular Hydroalkoxylation of Alkenes Catalyzed by PVP-Stabilized Nanogold

Kitahara, Hiroaki; Sakurai, Hidehiro

doi:10.3390/molecules17032579

Cited by 4 publications

(5 citation statements)

References 33 publications

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“…These results lead us to conclude that it is energetically favorable for the first step of the intramolecular hydroamination of 1 on Au 20 − to proceed by C−N bond formation through the anti ‐addition mechanism. The results agree well with the experimental observation that the reaction proceeded through anti ‐addition of the amine to the alkene, assisted by π‐activation of Au NC, which was observed in the hydroamination with toluenesulfonamides …”

Section: Resultsmentioning

confidence: 99%

“…Considering this result, we can conclude that the formation of 2 and carbonic acid through hydrogen transfer is the rate‐determining step for the intramolecular hydroamination of an unactivated alkene by a primary amine on Au 20 − under aerobic conditions. Here, we removed the possibility of a concerted hydrogen‐transfer process assisted by a H 2 O 2 molecule by isotope labeling experiments in which deuterium (D) introduced into the product is only from DCO 2 H, and not from D 2 O …”

Section: Resultsmentioning

confidence: 99%

“…The supported gold nanoparticle catalysts have been developed for a wide variety of reactions over many years . Gold nanoclusters (NCs) stabilized by water‐soluble polymers, for instance, poly( N ‐vinylpyrrolidone) (PVP), represented as Au:PVP, also serve as promising catalysts for the intramolecular hydroamination of unactivated alkenes under aerobic conditions . In contrast to Au I , the Lewis acid character of zero‐valent Au NCs is generated by the adsorption of O 2 , which allows the nucleophilic substrates to be adsorbed effectively on the Au surface and might play a key role as a catalytic center .…”

Section: Introductionmentioning

confidence: 99%

“…The use of Au:PVP enables intramolecular hydroamination of unactivated alkenes to be performed with toluenesulfonamide in aqueous or polar solvents under relatively basic and aerobic conditions, and can lead to highly selective formation of the desired products (Scheme b) . The investigation on the reaction mechanism suggested that the reaction proceeds preferentially through anti ‐addition of toluenesulfonamide to the alkene, which is assisted by π‐activation by the gold clusters . However, intramolecular hydroamination with the corresponding primary amine resulted in the formation of the cyclized product in only 3 % yield under similar conditions (Scheme b).…”

Section: Introductionmentioning

confidence: 99%

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Intramolecular Hydroamination by a Primary Amine of an Unactivated Alkene on Gold Nanoclusters: A DFT Study

2017

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Density functional theory calculations have been used to investigate the mechanism of intramolecular hydroamination of unactivated alkenes by using primary amines on gold nanoclusters (NCs) under aerobic conditions. By examining the activation modes in the cyclization process, the olefin activation mechanism was calculated to be the most energetically feasible of the three possible pathways. The amine activation pathway suffered from a high activation barrier, which means that this pathway is unlikely to take place on gold NCs. The catalytic cycle comprises five elementary steps: (1) adsorption of O2 on Au NCs results in superoxo‐like species and provides Lewis acidic sites that allow the nucleophilic substrate, 2,2‐diphenyl‐4‐penten‐1‐amine, to be adsorbed effectively; (2) intramolecular cyclization (C−N bond formation) takes place on the Au NCs through anti‐addition of the amino group; (3) hydroperoxy moiety formation by hydrogen transfer from the cyclic intermediate to superoxo‐like species; (4) the formation of hydrogen peroxide and (5) product involves hydrogen transfer from a hydrated formic acid. Natural bond orbital analysis of the transition states that arise during C−N bond formation reveals that anti‐addition of the substrate is preferred over the syn‐addition mechanism. A possible side reaction, the formation of 2‐methylene‐4,4‐diphenylpyrrolidine through β‐hydrogen elimination, is also discussed.

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Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Intramolecular Hydroamination by a Primary Amine of an Unactivated Alkene on Gold Nanoclusters: A DFT Study

2017

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“…In 2012 dienes were also reported to undergo intramolecular hydroalkoxylation in the presence of PPh 3 AuOTf [122]. The development of gold nanoclusters stabilized by the hydrophilic polymer poly(N-vinyl-2-pyrrolidone) was also reported to catalyze alkene hydroalkoxylation [123].…”

Section: Reactions Of Hydroxyalkenesmentioning

confidence: 99%

Synthesis of Saturated Heterocycles via Metal-Catalyzed Alkene Hydroamination or Hydroalkoxylation Reactions

Julian

2013

Topics in Heterocyclic Chemistry

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The intramolecular hydrofunctionalization of carbon-carbon multiple bonds has emerged as a powerful way to form cyclic structures. A particularly important class of reactions involves the use of amine or alcohol nucleophiles, and alkenes or allenes as electrophiles, to form pyrrolidine, piperidine, tetrahydrofuran, and tetrahydropyran heterocycles in a highly efficient manner using late transition metal catalysts. Asymmetric methods for hydroamination and hydroalkoxylation reactions have recently emerged, allowing for the enantioselective synthesis of such saturated heterocycles. This review covers recent developments (over the last 5-10 years) in late transition metal-catalyzed hydroamination and hydroalkoxylation reactions that generate saturated heterocycles.

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Gold Nanoparticles Stabilized by Molecular Fullerenols

et al. 2020

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Polyhydroxylated fullerene derivatives (fullerenols: C60(OH)12 and C60(OH)36) exhibit excellent stabilizing matrices for gold nanoparticles. Au:C60(OH)12 and Au:C60(OH)36 form hydrophilic colloids and are well dispersed in H2O, even though C60(OH)12 itself is barely dissolved in H2O. It was estimated that C60(OH)12 forms a two‐ to three‐layered structure with 3D O−H⋅⋅⋅O hydrogen‐bonding networks, surrounding approximately 3 nm‐sized Au NPs. The thus‐prepared Au:C60(OH)n colloids exhibited a high catalytic activity toward the reduction of 4‐nitrophenol to 4‐aminophenol. The short induction period as well as kinetic and thermodynamic parameters indicated the dynamic mobility of the fullerenol matrix and the hydrophobic nature of the interface between the Au surface and the matrix.

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Anti-Addition Mechanism in the Intramolecular Hydroalkoxylation of Alkenes Catalyzed by PVP-Stabilized Nanogold

Cited by 4 publications

References 33 publications

Intramolecular Hydroamination by a Primary Amine of an Unactivated Alkene on Gold Nanoclusters: A DFT Study

Intramolecular Hydroamination by a Primary Amine of an Unactivated Alkene on Gold Nanoclusters: A DFT Study

Synthesis of Saturated Heterocycles via Metal-Catalyzed Alkene Hydroamination or Hydroalkoxylation Reactions

Gold Nanoparticles Stabilized by Molecular Fullerenols

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