Aerobic Oxidation Of Amines Research Articles

Ruthenium hydroxide on magnetite as a magnetically separable heterogeneous catalyst for liquid-phase oxidation and reduction

Three kinds of reactions, (i) aerobic oxidation of alcohols, (ii) aerobic oxidation of amines, and (iii) reduction of carbonyl compounds to alcohols using 2-propanol as a hydrogen donor, could efficiently be promoted by an easily prepared ruthenium hydroxide catalyst on magnetite (Ru(OH)x/Fe3O4). A wide variety of substrates including aromatic, aliphatic, and heterocyclic ones could be converted to the desired products in high to excellent yields without any additives such as bases and electron transfer mediators. After the reaction, the catalyst/product(s) separation could be easily achieved with a permanent magnet and more than 99% of Ru(OH)x/Fe3O4 catalyst could usually be recovered for each reaction. The catalysis for these reactions was intrinsically heterogeneous, and Ru(OH)x/Fe3O4 recovered after these reactions could be reused without appreciable loss of the catalytic performance.

Enantioselective addition of aldehydes to amines via combined catalytic biomimetic oxidation and organocatalytic C–C bond formation

The biomimetic catalytic enantioselective addition of aldehydes to amines is reported. This was accomplished by combining biomimetic coupled catalytic aerobic oxidation of amines involving ruthenium-induced dehydrogenation and organocatalytic asymmetric Mannich reactions. The novel one-pot reactions furnished β-amino aldehyde and α-amino acid derivatives in high yields with excellent chemoselectivity and up to >99% ee.

Efficient Ruthenium‐Catalyzed Aerobic Oxidation of Amines by Using a Biomimetic Coupled Catalytic System

Efficient aerobic oxidation of amines was developed by the use of a biomimetic coupled catalytic system involving a ruthenium-induced dehydrogenation. The principle for this aerobic oxidation is that the electron transfer from the amine to molecular oxygen occurs stepwise via coupled redox systems and this leads to a low-energy electron transfer. A substrate-selective ruthenium catalyst dehydrogenates the amine and the hydrogen atoms abstracted are transported to an electron-rich quinone (2a). The hydroquinone thus formed is subsequently reoxidized by air with the aid of an oxygen-activating [Co(salen)]-type complex (27). The reaction can be used for the preparation of ketimines and aldimines in good to high yields from the appropriate corresponding amines. The reaction proceeds with high selectivity, and the catalytic system tolerates air without being deactivated. The rate of the dehydrogenation was studied by using quinone 2a as the terminal oxidant. A catalytic cycle in which the amine promotes the dissociation of the dimeric catalyst 1 is presented.

Copper‐Catalyzed Oxidation of Amines with Molecular Oxygen.

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Copper-Catalyzed Oxidation of Amines with Molecular Oxygen

Abstract An improved system for selective aerobic oxidation of amines to imines or nitriles is presented. It involves commercially available and inexpensive copper(I) or (II) chloride as catalyst, toluene as solvent, and MS3A as dehydrating agent under an atmospheric pressure of oxygen. A variety of amines can be used as substrates for this oxidation system to give the corresponding nitriles from primary amines (up to 97% yield; TON, up to 60) and the imines from secondary amines (up to 90% yield; TON, up to 45).

Efficient Heterogeneous Aerobic Oxidation of Amines by a Supported Ruthenium Catalyst.

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Efficient heterogeneous aerobic oxidation of amines by a supported ruthenium catalyst.

An inexpensive supported ruthenium catalyst (Ru/Al2O3) can be used to convert a broad range of primary (see scheme) and secondary amines into the corresponding nitriles and imines in high yields using either dioxygen or air as oxidants. The catalyst can be recycled and reused with no detectable loss of ruthenium and without an observed reduction in catalytic activity. Supporting information for this article is available on the WWW under http://www.wiley-vch.de/contents/jc_2002/2003/z50779_s.pdf or from the author. Please note: The publisher is not responsible for the content or functionality of any supporting information supplied by the authors. Any queries (other than missing content) should be directed to the corresponding author for the article.

Efficient Heterogeneous Aerobic Oxidation of Amines by a Supported Ruthenium Catalyst

Efficient Heterogeneous Aerobic Oxidation of Amines by a Supported Ruthenium Catalyst

An efficient aerobic oxidation of various organic compounds catalyzed by mixed addenda heteropolyoxometalates containing molybdenum and vanadium

Various organic compounds were oxidized by molecular oxygen in the presence of a catalytic amount of mixed-addenda heteropolyoxometalates containing molybdenum and vanadium. The catalytic activity of the molybdovanadophosphate was found to be greatly enhanced by supporting on charcoal. The supported catalyst has high catalytic activity for oxidative dehydrogenation of benzylic and allylic alcohols to the corresponding aldehydes and ketones (46–92%), nevertheless, the non-supported catalyst was inactive for the same oxidations under these conditions. 2,3,6-Trimethylphenol was selectively oxidized to trimethyl- p-benzoquinone, which is a precursor of vitamin E, in the presence of a catalytic amount of molybdovanadophosphate. In addition, the aerobic oxidation of amines, alkyl-substituted phenols, and alkanes were also examined.