Aerobic oxidation of amines

A similar reaction was reported by Meth-Cohn and Suschitzky [62], who obtained aldehydes from the aerobic oxidation of amines in neutral solution in the presence of a manganese dioxide catalyst. 

The selective aerobic oxidation of primary alcohols to aldehydes, but not secondary alcohols to ketones, is reminiscient of the chemistry catalyzed by the Cu-dependent enzyme, galactose oxidase (39). Similarly, the Cu-binding P-amyloid protein relevant to Alzheimer s disease promotes aerobic oxidation of cholesterol, a primary alcohol (cholesterol oxidase activity) (40). The Cu-dependent amine oxidases catalyze the aerobic oxidation of amines to aldehydes (41), the hydration products of imines. Each of these enzymes that promotes aerobic oxidation of primary alcohols and amines to the same products as Ni(TRISOX) catalyze the net reaction in Equation 1. If the net reactions... 

Recently, Kanai and Oisaki developed catalytic aerobic oxidation of amines using a combination of a Cu complex and a redox mediator keto-ABNO (31, Fig. 22) [162]. Keto-ABNO has greater oxidation potential than other N-oxyl radicals such as TEMPO and ABNO because of the electron-withdrawing ability... 

Schiimperli MT, Hammond C, Hermans I (2012) Developments in the aerobic oxidation of amines. ACS Catal 2(6) 1108-1117... 

More recently, Colonna and coworkers reported that cyclohexanone monooxygenase (CHMO) from Actinobacter calcoaceticus NCIMB9871 catalyzed the aerobic oxidation of amines [128]. 

Zhu, B., Lazar, M., Trewyn, B., et al. (2008). Aerobic Oxidation of Amines to hnines Catalyzed by Bulk Gold Powder and by Alumina-Supported Gold, J. Catal., 260, pp. 1-6. 

Recently, Kanai and co-workers developed a novel catalytic system for oxidation of benzyl amines and anilines to the corresponding imines with molecular ojg gen under mild conditions (Scheme 7.11). Inspired by Iwa-buchi s 2-azaadamantane-AI-03grl (AZADO) oxidation, they designed 9-azabi-cyclo[3.3.1]nonan-3-one AT-ojgrl (ketoABNO) as a more electron-deficient redox mediator and found that the combination with Cu(I) was effective for efficient aerobic oxidation of amines. Based on this result, they successfully applied their oxidation chemistry to CDC reactions. When the chiral Box ligand was used, an aerobic nitro-Mannich reaction between N-PMP glycine and 1-nitropropane proceeded with excellent diastereo- and enantioselectivity (20 1 diastereomeric ratio (dr) and 95% ee of the major syn isomer). In this case, EtgN was used as a co-catalyst to accelerate the addition reaction, because tertiary amines are inert to the ketoABNO/Cu(i) system. 

Scheme 5.10 Ruthenium-catalyzed aerobic oxidation of amines using a coupled catalytic system.

It was also reported by PruP et al. [31] that in situ formed cobalt(III) complexes of pyridine-4-ylmethyl-propyl-amine (PYPA) on preformed organomodified HMS are active as catalysts in the aerobic oxidation of styrene and also 1-decene (Figure 3). Incorporation of PYPA may be achieved by following several routes viz. sol-gel synthesis, post modification of sol-gel AMP-HMS, and grafting. The authors proposed that all materials are able to act as... 

James et al. reported that aerobic oxidation of primary amines in the presence of a ruthenium porphyrin complex Ru(TMP)(0)2 (TMP = tetramesitylporphyrinato) gives nitriles (100%) (Eq. 3.31) [66]. 

Heterogeneous catalysts such as hydroxyapatite-bound Ru complex [67] and Ru/ AI2O3 [68] can be also used for the aerobic oxidation of primary amines to nitriles (Eqs. 3.32 and 3.33). 

Very recently, Liu and coworkers reported a palladium-catalyzed intramolecular aerobic oxidative allylic amination of unactivated alkenes [34]. The reaction of 22... 

Copper amine oxidase (CAO) enzymes carry out the aerobic oxidation of primary amines to aldehydes (Scheme 14.8a). While copper is present in the active site, substrate oxidation proceeds by an organocatalytic pathway involving an o-quinone cofactor via a transamination mechanism (Scheme 14.8b). 

Through subtle modification of the reaction mechanism, the scope of o-quinone-catalyzed aerobic oxidations has been expanded to secondary amines and JV-heterocyclic compounds as well [45-47]. For example, aerobic oxidation of secondary amines and iV-heterocycles has been achieved by using 10-phenanthroline-5,6-dione (phd) as a catalyst (Scheme 14.10a). Using phd and cocatalytic Znl2, a diverse range of iV-heterocyclic compounds undergo... 

Scheme 14.8 Copper amine oxidases carry out (a) the aerobic oxidation of primary amines...

It is increasing interested in the utilization of heteropoly compounds as catalysts for the oxidation of various organic compounds. Recently, we have found that the mixed addenda heteropolyoxometallates such as (NH4)5H4PV0Mo0O4o 6H2O (PV0MO0) was efficient catalysts for the aerobic oxidation of olefinic compounds in the presence of isobutyraldehyde. We now present here the direct oxidation of amines and hydrocarbons with molecular oxygen by PV0MO0 catalyst. 

As a further extension, the Kim group very recently developed the aerobic oxidation and [l,5]-hydride transfer/cyclization sequence starting from readily available ortho tertiary amine substituted cinnamyl alcohols 24 (Scheme 4.12). The tetrapropylammonium perruthenate (TPAP) was identified as the competent catalyst for the initial aerobic oxidation of the allylic alcohols. The synthetically useful tetrahydroquinoline derivatives 25 were prepared in moderate yields and high level of enantioselectivity. 

Ru2(II,II) complexes are known to catalyze hydrogenation of alkenes and alkynes [235], cross-metathesis of alkenes [198], and intermolecular insertion of diazo compounds into 0-H bond [236]. Ru2(II,III) complexes catalyze the oxidative transformation of secondary amines to imines [237], aerobic oxidations of alcohols... 

Oxidative Amination of Alkenes. Palladium acetate-catalyzed aerobic oxidation of cyclopentene and cyclooctene using TcesNH2 affords the corresponding allylic amine products (eq 8). Small amounts of isomeric alkene products are also obtained in this reaction. 

Li X, Li S, Xu Q et al (2016) Efficient and practical catalyst-free-like dehydrative Af-alkylation of amines and sulfinamides with alcohols initiated by aerobic oxidation of alcohols under air. Tetrahedron 72(2) 264-272... 

Chen B, Wang L, Gao S (2015) Recent advances in aerobic oxidation of alcohols and amines to imines. ACS Catal 5(10) 5851-5876... 

An aerobic oxidation of tertiary amines catalyzed by Cobalt Schiff-base complexes afforded N-oxides in high yields [120]. The reaction was run at room temperature with 0.5 mol% of the cobalt catalyst 35 (Eq. (8.28)). The presence of molecular sieves (5 enhanced the rate of the reaction. With this procedure, various pyridines were oxidized to their corresponding N-oxides in yields ranging from 50 to 85%. Electron-deficient pyridines such as 4-cyanopyridine gave a slow reaction with only 50% yield. 

The same author also reported on an aerobic oxidation of tertiary amines and pyridines to their corresponding N-oxides catalyzed by ruthenium trichloride [121]. 

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