Baeyer-Villiger Oxidation Of Ketones Research Articles

Highly Selective Electrochemical Baeyer-Villiger Oxidation through Oxygen Atom Transfer from Water.

The Baeyer-Villiger oxidation of ketones is a crucial oxygen atom transfer (OAT) process used for ester production. Traditionally, Baeyer-Villiger oxidation is accomplished by thermally oxidizing the OAT from stoichiometric peroxides, which are often difficult to handle. Electrochemical methods hold promise for breaking the limitation of using water as the oxygen atom source. Nevertheless, existing demonstrations of electrochemical Baeyer-Villiger oxidation face the challenges of low selectivity. We report in this study a strategy to overcome this challenge. By employing a well-known water oxidation catalyst, Fe2O3, we achieved nearly perfect selectivity for the electrochemical Baeyer-Villiger oxidation of cyclohexanone. Mechanistic studies suggest that it is essential to produce surface hydroperoxo intermediates (M-OOH, where M represents a metal center) that promote the nucleophilic attack on ketone substrates. By confining the reactions to the catalyst surfaces, competing reactions (e.g., dehydrogenation, carboxylic acid cation rearrangements, and hydroxylation) are greatly limited, thereby offering high selectivity. The surface-initiated nature of the reaction is confirmed by kinetic studies and spectroelectrochemical characterizations. This discovery adds nucleophilic oxidation to the toolbox of electrochemical organic synthesis.

The catalytic activity of mycelial fungi towards 7-oxo-DHEA - an endogenous derivative of steroidal hormone dehydroepiandrosterone.

SummarySeventeen species of fungi belonging to thirteen genera were screened for the ability to carry out the transformation of 7‐oxo‐DHEA (7‐oxo‐dehydroepiandrosterone). Some strains expressed new patterns of catalytic activity towards the substrate, namely 16β‐hydroxylation (Laetiporus sulphureus AM498), Baeyer–Villiger oxidation of ketone in D‐ring to lactone (Fusicoccum amygdali AM258) and esterification of the 3β‐hydroxy group (Spicaria divaricata AM423). The majority of examined strains were able to reduce the 17‐oxo group of the substrate to form 3β,17β‐dihydroxy‐androst‐5‐en‐7‐one. The highest activity was reached with Armillaria mellea AM296 and Ascosphaera apis AM496 for which complete conversion of the starting material was achieved, and the resulting 17β‐alcohol was the sole reaction product. Two strains of tested fungi were also capable of stereospecific reduction of the conjugated 7‐keto group leading to 7β‐hydroxy‐DHEA (Inonotus radiatus AM70) or a mixture of 3β,7α,17β‐trihydroxy‐androst‐5‐ene and 3β,7β,17β‐trihydroxy‐androst‐5‐ene (Piptoporus betulinus AM39). The structures of new metabolites were confirmed by MS and NMR analysis. They were also examined for their cholinesterase inhibitory activity in an enzymatic‐based assay in vitro test.

Controllably Confined ZnO on USY Zeolites (USY@ZnO/Al2 O3 ) as Efficient Lewis Acid Catalysts for Baeyer-Villiger Oxidation.

A ZnAl-LDHs (layered double hydroxides) phase was readily formed on the surface of a USY zeolite through a distinctive in situ growth method that benefitted from the interaction of the added Zn source and aluminum species extracted from the Al-rich USY zeolite crystals. The migration of aluminum and simultaneous interaction with the external Zn source took place in one pot to form a ZnAl-LDHs phase coated on the surface of the USY crystals. Upon calcination, the ZnAl-LDHs phase was transformed into a ZnO/Al2 O3 composite that was still firmly anchored on the USY zeolite, without sacrificing the core-shell structure. The resultant USY@ZnO/Al2 O3 materials gave rise to unique Lewis acidity and hierarchical porosity, which endowed the catalyst with promising performance in the Baeyer-Villiger oxidation of ketones with H2 O2 or bulky tert-butyl hydroxide as an oxidant.

Efficient Baeyer-Villiger electro-oxidation of ketones with molecular oxygen using an activated carbon fiber electrode in ionic liquid [bmim][OTf

A new and efficient method for the synthesis of lactones and esters involving the application of an molecular oxygen-based electro-catalytic oxidation system and ionic liquid [bmim][OTf] as electrolyte has been developed. The reaction between various ketones with molecular oxygen proceeds in a three-electrode cell under constant current conditions in [bmim][OTf] at room temperature to give the corresponding esters and lactones in good to excellent isolated yield. Additionally, the possible mechanism of Baeyer-Villiger oxidation of ketones in the electro-catalytic system is proposed. KEY WORDS : Baeyer-Villiger oxidation, Ketone, Molecular oxygen, Electrocatalysis, Ionic liquid Bull. Chem. Soc. Ethiop. 2016 , 30(2), 297-306. DOI: http://dx.doi.org/10.4314/bcse.v30i2.14

Transformation pathways and acute toxicity variation of 4-hydroxyl benzophenone in chlorination disinfection process

Benzophenones compounds (BPs) are widely used as UV filters, and have been frequently found in multiple environmental matrices. The residual of BPs in water would cause potential threats on ecological safety and human health. Chlorination disinfection is necessary in water treatment process, in which many chemicals remained in water would react with disinfectant chlorine and form toxic by-products. By using ultra performance liquid phase chromatography quadrupole time of flight mass spectrometer (UPLC-QTOF-MS), nuclear magnetic resonance (NMR), the transformation of 4-hydroxyl benezophenone (4HB) with free available chlorine (FAC) was characterized. Eight major products were detected and seven of them were identified. Transformation pathways of 4HB under acid, neutral, and alkaline conditions were proposed respectively. The transformation mechanisms involved electrophilic chlorine substitution of 4HB, Baeyer-Villiger oxidation of ketones, hydrolysis of esters and oxidative breakage of benzene ring. The orthogonal experiments of pH and dosages of disinfectant chlorine were conducted. The results suggested that pH conditions determined the occurrence of reaction types, and the dosages of disinfectant chlorine affected the extent of reactions. Photobacterium assay demonstrated that acute toxicity had significant increase after chlorination disinfection of 4HB. It was proved that 3,5-dichloro-4HB, one of the major transformation products, was responsible for the increasing acute toxicity after chlorination. It is notable that, 4HB at low level in real ambient water matrices could be transformed during simulated chlorination disinfection practice. Especially, two major products 3-chloro-4HB and 3,5-dichloro-4HB were detected out, implying the potential ecological risk after chlorination disinfection of 4HB.

ChemInform Abstract: HOF×CH3CN, Made Directly from F2 and Water, as an Ecologically Friendly Oxidizing Reagent.

Abstract The complex HOF·CH3CN, made directly from fluorine and aqueous acetonitrile, was used for oxidation of secondary alcohols and for Baeyer Villiger oxidation of ketones. By using 18O labeled reagent it was found that the ketone oxidation proceeds through the original dioxirane mechanism which Baeyer and Villiger suggested a century ago for reactions with peracids but was later discounted.

Flavins as organocatalysts for environmentally benign molecular transformations

Recent progress in the development of flavin-catalyzed oxidations and related reactions is described with respect to scope, limitation, and reaction mechanism. The 4a-hydroperoxyflavins, which are the most simplified model compounds of flavoenzymes, act as catalytically active species for the oxidation of organic substrates with the help of H(2)O(2) or O(2) as a mild oxidant. This principle behind the simulation of flavoenzymes led to the discovery of a variety of environmentally benign, oxidative transformations of secondary amines to nitrones, tertiary amines to N-oxides, sulfides to sulfoxides, and Baeyer-Villiger oxidations of ketones. Asymmetric oxidation of sulfides can also be performed with several chiral flavin catalysts. One of the fortunate outcomes of this study is the development of an environmentally friendly ("green") method for the "aerobic hydrogenation" of olefins, which is achieved by in situ generation of diimide with the aid of the flavin-catalyzed oxidation of hydrazine under an O(2) atmosphere.

A Synthesis of Alibendol, 2‐Hydroxy‐N‐(2‐hydroxyethyl)‐3‐methoxy‐5‐(2‐propenyl)benzamide via m‐CPBA Oxidation of o‐Vanillin.

AbstractFor Abstract see ChemInform Abstract in Full Text.

A Synthesis of Alibendol, 2-Hydroxy-N-(2-hydroxyethyl)-3-methoxy-5-(2-propenyl)benzamide via m-CPBA Oxidation of o-Vanillin

A large number of methods for the conversion of aldehydes to esters have been reported in the literature over the last thirty years. 2 Baeyer-Villiger oxidation of ketones and aldehydes using peracid is frequently chosen due to its easy manipulation and high productivity. 3 However, the reaction of acyclic acetal derived from a ketone (a ketal) with peracid is known to be sluggish and to provide the orthocarbonate as the result of dual Baeyer-Villiger oxidation. 4 Several methods of direct oxidation of acetal to esters with oxidizing agents such as, peracetic acid, 5 chromium trioxide, 6 ozone, 7 tert-butylhydroperoxide, 8 PDC/ t-BuOOH, 9 NBS, 10 peroxymonosulfuric acid, 11 dimethyldioxirane, 12 or hydrogen peroxide 13 have been reported. Recently, we reported a facile procedure for the conversion of aldehydes to the corresponding esters via acetal formation from aldehydes and subsequent oxidation by m-CPBA with BF3·OEt2. 14 Based on our recent reports, we wish to utilize this methodology for the synthesis of biologically important compounds. Alibendol, 2-hydroxy-N-(2-hydroxyethyl)-3-methoxy-5(2-propenyl)benzamide is known as antispasmodic, chleretic, and cholekinetic active pharmaceutical ingredient (API) which is useful in treatment of dyspepsia due to biliary insufficiency, alimentary intolerance, urticaria, pruritus, migraine, and constipation of hepatic origin. 15

Synthesis of 3-Azabicyclo[3.3.0]octane Framework and a Novel Tricyclicaminoether

The efficient synthesis of 3-azabicyclo[3.3.0]octane derivative 1 and a novel tricyclicaminoether 11 has been achieved in seven steps using commercially available starting materials and commonly used reagents. The key steps are the intramolecular ring opening of epoxide 7 providing tricyclic aminoalcohol 3 and Baeyer-Villiger oxidation of ketone 8 providing the corresponding lactone 2. Both reactions proceeded regiospecifically.

Electrophilic activation of hydrogen peroxide: selective oxidation reactions in perfluorinated alcohol solvents.

[reaction; see text] The catalytic electrophilic activation of hydrogen peroxide with transition metal compounds toward reaction with nucleophiles is a matter of very significant research and practical interest. We have now found that use of perfluorinated alcoholic solvents such as 1,1, 1,3,3,3-hexafluoro-2-propanol in the absence of catalysts allowed electrophilic activation of hydrogen peroxide toward epoxidation of alkenes and the Baeyer-Villiger oxidation of ketones.

Synthesis of methyl 5-azido-5-deoxy-2,3- O-isopropylidenecarba- α-D- allo-hexafuranuronate, the sugar part of carbapolyoxins and carbanikkomycins

The sugar part of carbapolyoxins and carbanikkomycins, methyl 5-azido-5-deoxy-2,3- O-isopropylidenecarba- α-D- allo-hexafuranuronate ( 16), was synthesised starting from enantiomerically enriched norborn-5-en-2-yl acetate ( 2). For the introduction of the hydroxy groups and the azido functionality the rigidity of the norbornene skeleton provided the regioselective attack of the reagents. For the key step in this synthesis, the Baeyer-Villiger oxidation of ketone 6, a method was developed, which might either be used for the synthesis of Ohno's lactone 10 or the isomeric lactone 9.

Magnesium Oxide-Supported Polytitazane Copper(II) Complex Catalyzed Aerobic Baeyer-Villiger Oxidation of Ketones and Cyclohexanol in the Presence of Benzaldehyde

Magnesium oxide-supported polytitazane copper complex is prepared and found to be a very effective catalyst for the Baeyer-Villiger oxidation of ketones and cyclohexanol in the presence of an aldehyde as a reductant under an atmospheric pressure of oxygen at room temperature. The δ-valerolactone and δ-caprolactone can be obtained in high than 97% yield. The reactivity of ketones decreases as fellow: cycloketones > acetophenone > aliphatic ketone. It is found that cyclohexanol is selectively oxidized to ϵ-caprolactone in 77% yield and 89% selectivity by the above combined catalytic system. The catalyst is also very stable and can be reused at least six times without loss of its activity.

Baeyer-Villiger Oxidation of Ketones Using Molecular Oxygen and Benzaldehyde in the Absence of Metal Catalysts

A combination system of molecular oxygen, benzaldehyde, and carbon tetrachloride oxidizes various ketones to give lactones and esters in high yields at 40 o C, and addition of benzoyl chloride increases yields of the Baeyer-Villiger oxidation products at a lower temperature of 20 o C

HOF·CH 3CN, made directly from F 2 and water, as an ecologically friendly oxidizing reagent

The complex HOF·CH 3CN, made directly from fluorine and aqueous acetonitrile, was used for oxidation of secondary alcohols and for Baeyer Villiger oxidation of ketones. By using 18O labeled reagent it was found that the ketone oxidation proceeds through the original dioxirane mechanism which Baeyer and Villiger suggested a century ago for reactions with peracids but was later discounted.

Use of molecular oxygen in the Baeyer-Villiger oxidation the influence of metal catalysts

Baeyer-Villiger oxidation of ketones using molecular oxygen and benzaldehyde in the absence of metal catalysts afforded lactones in high yields. The catalytic activity of various metal salts has been studied.

Baeyer-Villiger oxidation of ketones by peroxomolybdenum complexes: A revisit

The Baeyer-Villiger oxidation of cyclopentanone to δ-valerolactone by a peroxomolybdenum complex, MoO(O) 2 (dipic), under catalytic (hydrogen peroxide) conditions was reported in the literature some years ago. Such a reaction might have both synthetic and mechanistic significance, being the only available example of nucleophilic reactivity of Group VI peroxometal complexes. However, the results of a reinvestigation of the reaction presented in this paper indicate that the oxidation is carried out by hydrogen peroxide and that the role of MoO(O) 2 (dipic) as well that of other molybdenum derivatives is simply to catalyze the reaction owing to their strong acid nature.

Functional group oxidation using sodium perborate1

Sodium perborate in acetic acid is an effective reagent for the oxidation of anilines to nitroarenes and of sulphides to either sulphoxides or sulphones. It is also an excellent reagent for the oxidative deprotection of ketone dimethylhydrazones. Baeyer-Villiger oxidation of ketones can be carried out with sodium perborate in either trifluoroacetic acid or acetic acid/trifluoroacetic acid mixtures, and hydroquinones and certain highly substituted phenols are smoothly converted into quinones.

Biphase and triphase catalysis. Arsonated polystyrenes as catalysts in the Baeyer-Villiger oxidation of ketones by aqueous hydrogen peroxide

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTBiphase and triphase catalysis. Arsonated polystyrenes as catalysts in the Baeyer-Villiger oxidation of ketones by aqueous hydrogen peroxideStephen E. Jacobson, Frank Mares, and Patrick M. ZambriCite this: J. Am. Chem. Soc. 1979, 101, 23, 6938–6946Publication Date (Print):November 1, 1979Publication History Published online1 May 2002Published inissue 1 November 1979https://doi.org/10.1021/ja00517a025RIGHTS & PERMISSIONSArticle Views410Altmetric-Citations54LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InReddit PDF (1012 KB) Get e-Alerts Get e-Alerts

Degradation of long chain alkanes by bacilli

Five different species of bacilli tested at 30°C degrade hydrocarbons by cooxidation. Subterminal degradation pathway of these bacilli was proved by estimating isomeric esters, developed from Baeyer-Villiger oxidation of ketones, and also by finding diols, ketols, and diketones. Comparing the composition of fatty acids in lipids of bacilli grown with and without alkane as well as growing them on labeled n-tridecane suggested a subterminal, partly a di-subterminal pathway.