Highly efficient oxidation of alcohols using Oxone as oxidant catalyzed by ruthenium complex under mild reaction conditions

Aromatic and alkyl alcohols were oxidized to the corresponding aldehydes or ketones at room temperature with high conversion and selectivity using Oxone （2KHSOs-KHSO4.K2SO4） as oxidant catalyzed by ruthenium complex Quin-Ru-Quin （where Quin = 8-hydroxyquinoline）. The reaction time is very short and the preparation of complex is simple.     

Oxidation of alkanes and alcohols with hydrogen peroxide catalyzed by complex Os3(CO)10(µ‐H)2

Trinuclear carbonyl hydride cluster, Os₃(CO)₁₀(µ‐H)₂, catalyzes oxidation of cyclooctane to cyclooctyl hydroperoxide by hydrogen peroxide in acetonitrile solution. The hydroperoxide partly decomposes in the course of the reaction to afford cyclooctanone and cyclooctanol. Selectivity parameters obtained in oxidations of various linear and branched alkanes as well as kinetic features of the reaction indicated that the alkane oxidation occurs with the participation of hydroxyl radicals. A similar mechanism operates in transformation of benzene into phenol and styrene into benzaldehyde. The system also oxidizes 1‐phenylethanol to acetophenone. The kinetic study led to a conclusion that oxidation of alcohols does not involve hydroxyl radicals as main oxidizing species and apparently proceeds with the participation of osmyl species, ‘Os?O’. Copyright © 2010 John Wiley & Sons, Ltd.     

Highly efficient oxidation of alcohols using Oxone(R) as oxidant catalyzed by ruthenium complex under mild reaction conditions

Aromatic and alkyl alcohols were oxidized to the corresponding aldehydes or ketones at room temperature with high conversion and selectivity using Oxone (2KHSO5·KHSO4·K2SO4) as oxidant catalyzed by ruthenium complex Quin-Ru-Quin (where Quin = 8-hydroxyquinoline). The reaction time is very short and the preparation of complex is simple. 2008 Zi Qiang Lei. Published by Elsevier B.V. on behalf of Chinese Chemical Society. All rights reserved.     

Carbon–carbon bond formation between secondary alcohols and aldehydes under ruthenium‐catalyzed redox shuttle

Secondary alcohols are coupled with aldehydes in dioxane in the presence of a catalytic amount of a ruthenium catalyst along with KOH to give coupled ketones or coupled secondary alcohols depending on the molar ratio of secondary alcohols to aldehydes and the presence (or absence) of a sacrificial hydrogen acceptor. Copyright © 2011 John Wiley & Sons, Ltd.     

Cobalt phthalocyanine catalyzed aerobic oxidation of secondary alcohols: an efficient and simple synthesis of ketones

A variety of activated and non-activated secondary alcohols have been efficiently oxidized to their corresponding ketones in excellent yields with molecular oxygen using cobalt phthalocyanine as catalyst in the presence of powdered potassium hydroxide.     

Oxidation of primary and secondary alcohols catalyzed by a pentamethylcyclopentadienyliridium complex

The oxidation of primary and secondary alcohols is carried out in acetone under mild conditions using catalytic amounts of [Cp*IrCl₂]₂ and K₂CO₃. Primary alcohols are converted into the corresponding aldehydes with high selectivity in good yields. Secondary alcohols are readily oxidized to ketones with smaller amounts of the catalyst.     

Catalytic oxidation of alcohols with polymer-supported ruthenium complex under mild conditions

Polymer-supported ruthenium-containing complex PS–Phen–Ru was synthesized (where PS = chloromethyl polystyrene resin, Phen = 1,10-phenanthroline) and was characterized by FT-IR, ICP, and XPS. The supported complex was used to catalyze the oxidation of primary aliphatic alcohols as well as aromatic alcohols in the presence of iodosylbenzene. The oxidations were carried out in acetonitrile solution, affording the corresponding aldehydes or ketones in high substrate conversion and high selectivities under mild reaction conditions. The catalyst can be easily prepared and can be recycled.     

Highly efficient and selective oxidation of secondary alcohols to ketones under organic solvent and transition metal free conditions

The aqueous HBr/H₂O₂ was found to be highly efficient and green catalytic system for the selective oxidation of the secondary alcohols to ketones in excellent yields under organic solvent free conditions. The results of the oxidation of the secondary alcohols with solid alternatives of the aqueous hydrogen peroxide like SPC or SPB are also described.     

Selective oxidation of benzylic,allylic and propargylic alcohols using dirhodium(II) tetraamidinate as catalyst and aqueous tert‐butyl hydroperoxide as oxidant

We show that the dirhodium(II) tetraamidinate complex Rh₂(Msip)₄ efficiently catalyzes the oxidation of activated secondary alcohols at only 0.1 mol% loading. In this approach, we oxidized various benzylic, allylic and propargylic alcohols to the corresponding carbonyl compounds under mild aqueous conditions using the inexpensive oxidant T‐HYDRO® (70 wt% aqueous tert‐butyl hydroperoxide). Copyright © 2015 John Wiley & Sons, Ltd.     

Mixed metal MgO–ZrO2 nanoparticle‐catalyzed O‐tert‐Boc protection of alcohols and phenols under solvent‐free conditions

An environmentally benign method for O‐tert‐Boc protection of alcohols and phenols catalyzed by MgO–ZrO₂ nanoparticles under solvent‐free conditions is described. A variety of phenols, alcohols (aliphatic and aromatic) were converted to corresponding O‐tert‐Boc products in good to excellent yield (50–95%). The present protocol is expedient, simple, and efficient under solvent‐free conditions. The MgO–ZrO₂ Nps are easily prepared from inexpensive precursors, and are reusable, recyclable and chemoselective. Copyright © 2012 John Wiley & Sons, Ltd.     

Application and Mechanistic Studies of a Water‐Oxidation Catalyst in Alcohol Oxidation by Employing Oxygen‐Transfer Reagents

By using a dimeric ruthenium complex in combination with tert‐butyl hydrogen peroxide (TBHP) as stoichiometric oxidant, a mild and efficient protocol for the oxidation of secondary benzylic alcohols was obtained, thereby giving the corresponding ketones in high yields within 4 h. However, in the oxidation of aliphatic alcohols, the TBHP protocol suffered from low conversions owing to a competing Ru‐catalyzed disproportionation of the oxidant. Gratifyingly, by switching to Oxone (2 KHSO₅ ? KHSO₄ ? K₂SO₄ triple salt) as stoichiometric oxidant, a more efficient and robust system was obtained that allowed for the oxidation of a wide range of aliphatic and benzylic secondary alcohols, giving the corresponding ketones in excellent yields. The mechanism for these reactions is believed to involve a high‐valent Ru^V–oxo species. We provide support for such an intermediate by means of mechanistic studies.     

Catalytic oxyfunctionalization of alkanes by manganese and ruthenium clusters

Di- and trinuclear clusters of manganese and ruthenium were used as catalysts in the oxidation of alkanes in the presence oftert-butyl hydroperoxide as oxidant. The investigations reveal marked differences in the reactivity of the manganese and ruthenium catalysts though structurally they have similar coordination environment. The probable mechanism of hydroxylation in these systems is discussed.     

Salen-Mn（Ⅲ）-Complex-Catalyzed Oxidations of Secondary Alcohols

Secondary alcohols were catalytically oxidized with diace-toxyiodobenzene as oxidant in the presence of salen-Mn(Ⅲ)complex to aiTord the eorrespoltding ketones, in up to 99% yield, using CH2Cl2 or water as reaction media.     

Synthesis of a series of new ruthenium organometallic complexes derived from pyridine‐imine ligands and their catalytic activity in oxidation of secondary alcohols

Reactions of pyridine imines [C₅H₄N‐2‐C(H) = N‐C₆H₄‐R] [R = H (1), CH₃ (2), OMe (3), CF₃ (4), Cl (5), Br (6)] with Ru₃(CO)₁₂ in refluxing toluene gave the corresponding dinuclear ruthenium carbonyl complexes of the type {μ‐η²‐CH[(2‐C₅H₄N)(N‐C₆H₄‐R)]}₂Ru₂(CO)₄(μ‐CO) [R = H (7); CH₃ (8); OMe (9); CF₃ (10); Cl (11); Br (12)]. All six novel complexes were separated by chromatography, and fully characterized by elemental analysis, IR, NMR spectroscopy. Molecular structures of 7, 10, 11, and 12 were determined by X‐ray crystal diffraction. Further, the catalytic performance of these complexes was also tested. The combination of {μ‐η²‐CH[(2‐C₅H₄N)(N‐C₆H₄‐R)]}₂Ru₂(CO)₄(μ‐CO) and NMO afforded an efficient catalytic system for the oxidation of a variety secondary alcohols.     

Polystyrene‐supported Pd(II) complex‐catalysed carboacylation of 2‐arylpyridines with alcohols via C─H bond activation under solvent‐free conditions

Polystyrene‐supported N ,N ‐dimethylethylenediamine Pd(II) complex C was used as an efficient catalyst for the synthesis of aromatic ketones via ortho ‐acylation of sp² C─H bonds of 2‐arylpyridines with alcohols as effective coupling partners. The alcohols were oxidized with tert ‐butyl hydroperoxide to their corresponding aldehydes in situ and efficiently coupled with 2‐arylpyridines to form aryl ketones under solvent‐free conditions. Furthermore, catalyst C could be easily recovered by simple filtration and reused for five cycles without any significant decrease in its activity.     

Oxidation of secondary alcohols byN-methylmorpholine-N-oxide (NMO) catalyzed by atrans-dioxo ruthenium(VI) complex or perruthenate complex: A kinetic study

Thetrans-dioxo ruthenium (VI) complex, [P(C₆H₅)₃C₆H₅CH₂]⁺[Ru(O)₂OAcCl₂] or tetrapropylammonium perruthenate catalyzes the oxidation of secondary alcohols to ketones byN-methylmorpholine-N-oxide (NMO). Kinetic studies showed the formation of a complex between catalyst and substrate (alcohol) as the first step in the mechanism.     

CuCl catalyzed selective oxidation of primary alcohols to carboxylic acids with tert-butyl hydroperoxide at room temperature

Direct oxidation of primary alcohols to the corresponding carboxylic acids is performed highly efficiently at room temperature with anhydrous tert-butyl hydroperoxide in the presence of a catalytic amount of easily available CuCl under ligand free conditions in acetonitrile. Benzylic alcohols are more reactive than aliphatic alcohols, and these benzylic alcohols are selectively oxidized to the corresponding acids in the presence of aliphatic alcohols such as 1-octanol and 1-decanol.     

Ruthenium‐Catalyzed Oxidation of Alkenes,Alkynes, and Alcohols to Organic Acids with Aqueous Hydrogen Peroxide

A protocol that adopts aqueous hydrogen peroxide as a terminal oxidant and [(Me₃tacn)(CF₃CO₂)₂Ru^III(OH₂)]CF₃CO₂ ( 1 ; Me₃tacn=1,4,7‐trimethyl‐1,4,7‐triazacyclononane) as a catalyst for oxidation of alkenes, alkynes, and alcohols to organic acids in over 80 % yield is presented. For the oxidation of cyclohexene to adipic acid, the loading of 1 can be lowered to 0.1 mol %. On the one‐mole scale, the oxidation of cyclohexene, cyclooctene, and 1‐octanol with 1 mol % of 1 produced adipic acid (124 g, 85 % yield), suberic acid (158 g, 91 % yield), and 1‐octanoic acid (129 g, 90 % yield), respectively. The oxidative C?C bond‐cleavage reaction proceeded through the formation of cis‐ and trans‐diol intermediates, which were further oxidized to carboxylic acids via C? C bond cleavage.     

Baeyer-Villiger oxidation of ketones with hydrogen peroxide catalyzed by Sn-aniline complex

Sn-aniline complex was prepared by a simple procedure.Cyclic and acyclic ketones were oxidized into lactones or esters with very high selectivity and yield with 30% hydrogen peroxide in the presence of Sn-aniline complex.