Nitroxide-catalyzed oxidation of alcohols using m-chloroperbenzoic acid. New method

Cella, James A.; Kelley, James A.; Kenehan, Edward F.

doi:10.1021/jo00900a049

Cited by 161 publications

(67 citation statements)

References 2 publications

(2 reference statements)

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…The oxoammonium cation can also be generated in situ using single oxygen donors such as m-chloroperbenzoic acid, [58] sodium bromite, [54] sodium chlorite, [60] persulfate (oxone), [61] periodic acid (H 5 IO 6 ), [62] and sodium hypochlorite. [63] In particular the TEMPO/hypochlorite (household bleach) protocol, using 1 mol % TEMPO in combination with 10 mol % sodium bromide as co-catalyst in dichloromethane/water at pH 9 and 0 8C, has been widely applied in organic synthesis.…”

Section: ð10þmentioning

confidence: 99%

Organocatalytic Oxidations Mediated by Nitroxyl Radicals

2004

View full text Add to dashboard Cite

The use of nitroxyl radicals, alone or in combination with transition metals, as catalysts in oxidation processes is reviewed from both a synthetic and a mechanistic viewpoint. Two extremes of reactivity can be distinguished: stable (persistent) dialkylnitroxyls, such as the archetypal TEMPO, and reactive diacylnitroxyls, derived from N-hydroxy imides, such as N-hydroxyphthalimide (NHPI). The different types of reactivity observed are rationalized by considering the bond dissociation energies (BDEs) of the respective N-hydroxy precursors, substrates and reaction intermediates. Reactive diacylnitroxyl radicals are generated in situ from the corresponding N-hydroxy compound. The protagonist, NHPI, catalyzes a wide variety of free radical autoxidations, improving both activities and selectivities by increasing the rate of chain propagation and/or decreasing the rate of chain termination. In the absence of metal co-catalysts improved conversions and selectivities are obtained in the autoxidation of hydrocarbons to the corresponding alkyl hydroperoxides. For example, cyclohexylbenzene afforded the 1-hydroperoxide in 97.6% selectivity at 32% conversion when the autoxidation was performed in the presence of 0.5 mol % NHPI, and the product hydroperoxide as initiator, at 100 8C. This forms the basis for a potential coproduct-free route from benzene to phenol. In combination with transition metal co-catalysts, notably cobalt, NHPI and related compounds, such as N-hydroxysaccharin NHS, afford effective catalytic systems for the effective autoxidation of hydrocarbons, e.g., toluenes to carboxylic acids, under mild conditions. In the case of the less reactive cycloalkanes, NHS proved to be a more active catalyst than NHPI which is attributed to the higher reactivity of the intermediate nitroxyl radical, resulting from the replacement of a carbonyl group in NHPI by the more strongly electron-attracting sulfonyl group. Stable dialkylnitroxyl radicals, exemplified by TEMPO, catalyze oxidations of, e.g., alcohols, with single oxygen donors such as hypochlorite and organic peracids. The reactions involve the intermediate formation of the corresponding oxoammonium cation as the active oxidant. Alternatively, in conjunction with transition metals, notably ruthenium and copper, they catalyze aerobic oxidations of alcohols. These reactions involve metal-centered dehydrogenations and the role of the TEMPO is to facilitate regeneration of the catalyst (Ru and Cu) and oxidation of the alcohol (Cu) via hydrogen abstraction or one-electron oxidation processes. Detailed mechanistic investigations, including kinetic isotope effects, revealed that oxoammonium cations are not involved as intermediates in these reactions. In contrast, oxoammonium cations are involved in the aerobic oxidation of alcohols catalyzed by the copper-dependent oxidase, laccase, in combination with TEMPO. This different mechanistic pathway is attributed to the much higher redox potential of the copper(II) in the enzyme. Similarly, N-hydroxy compounds such as ...

show abstract

Section: ð10þmentioning

confidence: 99%

Organocatalytic Oxidations Mediated by Nitroxyl Radicals

2004

View full text Add to dashboard Cite

show abstract

“…Examples of alcoholic compounds oxidation strategies using TEMPO and derivatives. (A) Oxidation of ethanol onto acetaldehyde 177 using 4-hydroxy-2,2,6,6-tetramethyl-1-oxopiperidin-1-ium (1) (adapted from Golubev et al, 1966); (B) oxidation of (3,5-dimethoxyphenyl)-178 methanol onto 3,5-dimethoxybenzoic acid using 2,2,6,6-tetramethylpiperidine (2) and m-chloroperbenzoic acid (adapted from Cella et al, 1975); 179 (C) general oxidation of alcohol onto carboxylic acid using Water/CH 2 Cl 2 biphasic system and 4-methoxy-TEMPO/NaOCl/KBr/NaHCO 3 (3) 180 galactomannan) compared to cold-water-insoluble systems (such as chitin, chitosan, 238 amylopectin) gave better results in terms of oxidation degree or final molecular weight (Bragd 239 et al, 2004). Table 1 gives a large overview of recent TEMPO-mediated oxidation of 240 carbohydrates using different oxidant systems and their polyuronic analogues.…”

Section: Introduction 28mentioning

confidence: 99%

TEMPO-mediated oxidation of polysaccharides: An ongoing story

Pierre

Punta

Delattre

et al. 2017

Carbohydrate Polymers

136

View full text Add to dashboard Cite

15The oxidation of natural polysaccharides by TEMPO has become by now an "old chemical 16 reaction" which led to numerous studies mainly conducted on cellulose. This regioselective 17 oxidation of primary alcohol groups of neutral polysaccharides has generated a new class of 18 polyuronides not identified before in nature, even if the discovery of enzymes promoting an 19 analogous oxidation has been more recently reported. Around the same time, the scientific 20 community discovered the surprising biological and techno-functional properties of these 21 anionic macromolecules with a high potential of application in numerous industrial fields. The 22 objective of this review is to establish the state of the art of TEMPO chemistry applied to 23 polysaccharide oxidation, its history, the resulting products, their applications and the 24 associated modifying enzymes. 25

show abstract

“…[4][5][6][7][8][9][10][11] In recent years, a stable class of nitroxyl radicals, 12) as exemplified by 2,2,6,6-tetramethyl piperidinyl 1-oxyl (TEMPO) [(1); Chart 1], has extensively been used as a catalyst for oxidation of alcohols, because TEMPO is readily available from chemical suppliers at a reasonable price, and because the method allows the use of various safe bulk oxidants, thereby offering safe and extremely efficient oxidation of alcohols with considerable operational simplicity. [13][14][15][16][17][18][19][20][21][22][23][24][25] Today, TEMPOcatalyzed alcohol oxidation has high priority not only in academic laboratories, but also in the chemical industries, particularly in the pharmaceutical industry, as an efficient, mild, and environmentally acceptable method.…”

Section: Introductionmentioning

confidence: 99%

Discovery and Exploitation of AZADO: The Highly Active Catalyst for Alcohol Oxidation

Iwabuchi

2013

Chem. Pharm. Bull.

108

View full text Add to dashboard Cite

The oxidation of primary and secondary alcohols to the corresponding aldehydes (or carboxylic acids) or ketones is a fundamental transformation in organic synthesis. Stable organic nitroxyl radicals as represented by 2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPO) (1) have been used extensively to catalyze the oxidation of a number of alcohol substrates employing environmentally benign co-oxidants such as bleach (NaOCl) or PhI(OAc) 2 . Although TEMPO oxidation is better known as a method for selective oxidation of primary alcohols to the corresponding aldehydes, the TEMPO-based method is not very efficient for the oxidation of structurally hindered secondary alcohols. We designed and synthesized 2-azaadamantane N-oxyl [AZADO (

show abstract

Nitroxide-catalyzed oxidation of alcohols using m-chloroperbenzoic acid. New method

Cited by 161 publications

References 2 publications

Organocatalytic Oxidations Mediated by Nitroxyl Radicals

Organocatalytic Oxidations Mediated by Nitroxyl Radicals

TEMPO-mediated oxidation of polysaccharides: An ongoing story

Discovery and Exploitation of AZADO: The Highly Active Catalyst for Alcohol Oxidation

Contact Info

Product

Resources

About