Direct Dehydrogenative Amide Synthesis from Alcohols and Amines Catalyzed by γ‐Alumina Supported Silver Cluster

Shimizu, Ken‐ichi; Ohshima, Kan-ichi; Satsuma, Atsushi

doi:10.1002/chem.200901896

Cited by 193 publications

(99 citation statements)

References 40 publications

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“…The reaction presumably occurs by initial dehydrogenation of the alcohol to the aldehyde followed by hemiaminal formation with the amine and subsequent dehydrogenation to the amide. The amidation has been achieved both in the presence [14,15] and absence [16][17][18] of hydrogen scavengers. The latter protocol is the most attractive in which no stoichiometric additives are necessary and dihydrogen is produced as the only byproduct.…”

Section: A C H T U N G T R E N N U N G (Iipr)a C H T U N G T R E N N mentioning

confidence: 99%

“…[17,19] In 2009, Shimizu et al achieved the dehydrogenative amide synthesis with a silver cluster supported on g-alumina as the catalyst. [18] Of these three systems the in situ generated ruthenium carbene catalyst is easily modified and can be carried out with commercially available reagents.…”

Section: A C H T U N G T R E N N U N G (Iipr)a C H T U N G T R E N N mentioning

confidence: 99%

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Amide Synthesis from Alcohols and Amines Catalyzed by Ruthenium N‐Heterocyclic Carbene Complexes

Dam

Osztrovszky

Nordstrøm

et al. 2010

Chemistry A European J

175

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The direct synthesis of amides from alcohols and amines is described with the simultaneous liberation of dihydrogen. The reaction does not require any stoichiometric additives or hydrogen acceptors and is catalyzed by ruthenium N-heterocyclic carbene complexes. Three different catalyst systems are presented that all employ 1,3-diisopropylimidazol-2-ylidene (IiPr) as the carbene ligand. In addition, potassium tert-butoxide and a tricycloalkylphosphine are required for the amidation to proceed. In the first system, the active catalyst is generated in situ from [RuCl(2)(cod)] (cod=1,5-cyclooctadiene), 1,3-diisopropylimidazolium chloride, tricyclopentylphosphonium tetrafluoroborate, and base. The second system uses the complex [RuCl(2)(IiPr)(p-cymene)] together with tricyclohexylphosphine and base, whereas the third system employs the Hoveyda-Grubbs 1st-generation metathesis catalyst together with 1,3-diisopropylimidazolium chloride and base. A range of different primary alcohols and amines have been coupled in the presence of the three catalyst systems to afford the corresponding amides in moderate to excellent yields. The best results are obtained with sterically unhindered alcohols and amines. The three catalyst systems do not show any significant differences in reactivity, which indicates that the same catalytically active species is operating. The reaction is believed to proceed by initial dehydrogenation of the primary alcohol to the aldehyde that stays coordinated to ruthenium and is not released into the reaction mixture. Addition of the amine forms the hemiaminal that undergoes dehydrogenation to the amide. A catalytic cycle is proposed with the {(IiPr)Ru(II)} species as the catalytically active components.

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Section: A C H T U N G T R E N N U N G (Iipr)a C H T U N G T R E N N mentioning

confidence: 99%

Section: A C H T U N G T R E N N U N G (Iipr)a C H T U N G T R E N N mentioning

confidence: 99%

Amide Synthesis from Alcohols and Amines Catalyzed by Ruthenium N‐Heterocyclic Carbene Complexes

Dam

Osztrovszky

Nordstrøm

et al. 2010

Chemistry A European J

175

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“…Amides and H2 47) Amides are functional groups of great importance in polymers, natural products, and pharmaceuticals. Synthesis of amides is mostly based on activated acid derivatives (acid chlorides and anhydrides) or rearrangement reactions induced by an acid or base 72), 73) .…”

Section: Coupling Of Alcohols With Amines To Formmentioning

confidence: 99%

Silver Cluster Catalysts for Green Organic Synthesis

Shimizu

Satsuma

2011

J. Jpn. Petrol. Inst.

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Development of platinum-group-metal (PGM)-free catalysts for green chemical synthesis is an important topic in synthetic catalysis, because PGM will soon be in short supply in the near future. Our group has paid attention to the catalytic functions of Ag clusters. Here, we summarize our recent work on size-and support-specific catalysis of Ag clusters for green organic synthesis. Ag clusters supported on Al2O3 act as effective heterogeneous catalysts for (1) oxidant-free dehydrogenation of alcohols to carbonyl compounds, (2) coupling of alcohols with amines to form amides and H2, (3) N-alkylation of anilines with alcohols, (4) C _ C cross-coupling reaction of alcohols, (5) selective hydrogenation of nitroaromatics, and (6) direct synthesis of N-substituted anilines from nitroaromatics and alcohols. To establish a catalyst design concept, effects of Ag particle size and acid-base character of support oxides are investigated. The structure-activity relationships for all reactions show similar tendencies; metallic Ag clusters with smaller size and acid-base bifunctional nature of the support oxide are preferable. We propose that cooperation between coordinatively unsaturated Ag sites of Ag clusters and acidbase pair sites at the metal-support interface is a key concept for the design of Ag cluster catalysts for the above reactions.

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“…Since Naota's and Murahashi's report of Ru-catalyzed intramolecular oxidative amidation reactions from 1,4-and 1,5-amino alcohols to form lactams, [3] several groups have reported amide formation from alcohols with the aid of Ru, [5][6][7] Rh, [8] and Ag [9] catalysts. Among them, Ru complexes have been most extensively investigated.…”

Section: Introductionmentioning

confidence: 99%

Simple RuCl₃‐Catalyzed Amide Synthesis from Alcohols and Amines

Ghosh

Hong

2010

Eur J Org Chem

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A catalyst for the direct synthesis of amides from amines and alcohols, generated in situ from the economically attractive and readily available RuCl3, an N‐heterocyclic carbene (NHC), and pyridine, was developed. Of the screened NHC precursors, a less bulky one gave better yields for modestly sterically hindered substrates. In a search for the true catalytic intermediates, Grubbs catalysts were found to be active for the amidation of alcohols under basic conditions, suggesting that an Ru complex supported by an NHC ligand can catalyze the reaction.

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Direct Dehydrogenative Amide Synthesis from Alcohols and Amines Catalyzed by γ‐Alumina Supported Silver Cluster

Cited by 193 publications

References 40 publications

Amide Synthesis from Alcohols and Amines Catalyzed by Ruthenium N‐Heterocyclic Carbene Complexes

Amide Synthesis from Alcohols and Amines Catalyzed by Ruthenium N‐Heterocyclic Carbene Complexes

Silver Cluster Catalysts for Green Organic Synthesis

Simple RuCl₃‐Catalyzed Amide Synthesis from Alcohols and Amines

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Direct Dehydrogenative Amide Synthesis from Alcohols and Amines Catalyzed by γ‐Alumina Supported Silver Cluster

Cited by 193 publications

References 40 publications

Amide Synthesis from Alcohols and Amines Catalyzed by Ruthenium N‐Heterocyclic Carbene Complexes

Amide Synthesis from Alcohols and Amines Catalyzed by Ruthenium N‐Heterocyclic Carbene Complexes

Silver Cluster Catalysts for Green Organic Synthesis

Simple RuCl3‐Catalyzed Amide Synthesis from Alcohols and Amines

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Simple RuCl₃‐Catalyzed Amide Synthesis from Alcohols and Amines