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Photoinduced FeCl3-Catalyzed Alkyl Aromatics Oxidation toward Degradation of Polystyrene at Room Temperature?
While polystyrene is widely used in daily life as a synthetic plastic, the subsequently selective degradation is still very challenging and highly required. Herein, we disclose a highly practical and selective reaction for the catalytically efficient oxidation of alkyl aromatics (including 1°, 2°, and 3° alkyl aromatics) to carboxylic acids. While dioxygen was used as the sole terminal oxidant, this protocol was catalyzed by the inexpensive and readily available ferric compound (FeCl3) with irradiation of visible light (blue LEDs) under only 1 atmosphere of O2 at room temperature. This system could further facilitate the selective degradation of polystyrene to benzoic acid, providing an important and practical tool to generate high-value chemical from abundant polystyrene wastes.
Zhang, Guoxiang,Zhang, Zongnan,Zeng, Rong
supporting information
p. 3225 - 3230
(2021/09/28)

Acetyl nitrate mediated conversion of methyl ketones to diverse carboxylic acid derivatives
The development of a novel acetyl nitrate mediated oxidative conversion of methyl ketones to carboxylic acid derivatives is described. By analogy to the haloform reaction and supported by experimental and computational investigation we propose a mechanism for this transformation.
Bernard, Josephine,Capilato, Joseph N.,Hoy, Erik P.,Mattiucci, Joseph,Pellegrinelli, Peter J.,Perez, Lark J.,Philippi, Shane,Schnorbus, Logan
supporting information
p. 5298 - 5302
(2021/06/30)

Efficiency of lithium cations in hydrolysis reactions of esters in aqueous tetrahydrofuran
Lithium cations were observed to accelerate the hydrolysis of esters with hydroxides (KOH, NaOH, LiOH) in a water/tetrahydrofuran (THF) two-phase system. Yields in the hydrolysis of substituted benzoates and aliphatic esters using the various hydroxides were compared, and the effects of the addition of lithium salt were examined. Moreover, it was presumed that a certain amount of LiOH was dissolved in THF by the coordination of THF with lithium cation and hydrolyzed esters even in the THF layer, as in the reaction by a phase-transfer catalyst.
Harada, Yumi,Hayashi, Kazuhiko,Ichimaru, Yoshimi,Imai, Masanori,Kojima, Yuki,Maeda, Azusa,Nakayama, Kanae,Sugiura, Kirara
p. 581 - 594
(2021/06/06)

Aerobic oxidation of aldehydes to carboxylic acids catalyzed by recyclable ag/c3 n4 catalyst
The oxidation of aldehydes is an efficient methodology for the synthesis of carboxylic acids. Herein we hope to report a simple, efficient and recyclable protocol for aerobic oxidation of aldehydes to carboxylic acid by using C3N4 supported silver nanoparticles (Ag/C3N4) as a catalyst in aqueous solution under mild conditions. Under standard conditions, the corresponding carboxylic acids can be obtained in good to excellent yields. In addition, Ag/C3N4 is convenient for recovery and could be reused three times with satisfactory yields.
Wu, Chaolong,Yao, Xiaoquan,Yu, Min,Zhou, Li,Zhu, Li
p. 167 - 175
(2021/03/19)

One-Pot Direct Oxidation of Primary Amines to Carboxylic Acids through Tandem ortho-Naphthoquinone-Catalyzed and TBHP-Promoted Oxidation Sequence
Biomimetic oxidation of primary amines to carboxylic acids has been developed where the copper-containing amine oxidase (CuAO)-like o-NQ-catalyzed aerobic oxidation was combined with the aldehyde dehydrogenase (ALDH)-like TBHP-mediated imine oxidation protocol. Notably, the current tandem oxidation strategy provides a new mechanistic insight into the imine intermediate and the seemingly simple TBHP-mediated oxidation pathways of imines. The developed metal-free amine oxidation protocol allows the use of molecular oxygen and TBHP, safe forms of oxidant that may appeal to the industrial application.
Kim, Hun Young,Oh, Kyungsoo,Si, Tengda
supporting information
p. 18150 - 18155
(2021/12/09)

Cleavage of Carboxylic Esters by Aluminum and Iodine
A one-pot procedure for deprotecting carboxylic esters under nonhydrolytic conditions is described. Typical alkyl carboxylates are readily deblocked to the carboxylic acids by the action of aluminum powder and iodine in anhydrous acetonitrile. Cleavage of lactones affords the corresponding ω-iodoalkylcarboxylic acids. Aryl acetylates undergo deacetylation with the participation of the neighboring group. This method enables the selective cleavage of alkyl carboxylic esters in the presence of aryl esters.
Sang, Dayong,Yue, Huaxin,Fu, Yang,Tian, Juan
p. 4254 - 4261
(2021/03/09)

Selective oxidation of alkenes to carbonyls under mild conditions
Herein, a practical and sustainable method for the synthesis of aldehydes, ketones, and carboxylic acids from an inexpensive olefinic feedstock is described. This transformation features very sustainable and mild conditions and utilizes commercially available and inexpensive tetrahydrofuran as the additive, molecular oxygen as the sole oxidant and water as the solvent. A wide range of substituted alkenes were found to be compatible, providing the corresponding carbonyl compounds in moderate-to-good yields. The control experiments demonstrated that a radical mechanism is responsible for the oxidation reaction.
Huo, Jie,Xiong, Daokai,Xu, Jun,Yue, Xiaoguang,Zhang, Pengfei,Zhang, Yilan
supporting information
p. 5549 - 5555
(2021/08/16)

Combining photoredox catalysis and oxoammonium cations for the oxidation of aromatic alcohols to carboxylic acids
A methodology is reported for converting alcohols to the corresponding carboxylic acids. A dual catalytic system involving a merger of photoredox catalysis and 4-acetamido-TEMPO is employed to carry out this oxidation process.
Nandi, Jyoti,Hutcheson, Ellen L.,Leadbeater, Nicholas E.
supporting information

(2020/12/25)

Catalytic C-H aerobic and oxidant-induced oxidation of alkylbenzenes (including toluene derivatives) over VO2+immobilized on core-shell Fe3O4?SiO2at room temperature in water
Direct C-H bond oxidation of organic materials, and producing the necessary oxygenated compounds under mild conditions, has attracted increasing interest. The selective oxidation of various alkylbenzenes was carried out by means of a new catalyst containing VO2+ species supported on silica-coated Fe3O4 nanoparticles using t-butyl hydroperoxide as an oxidant at room temperature in H2O or solvent-free media. The chemical and structural characterization of the catalyst using several methods such as FTIR spectroscopy, XRD, FETEM, FESEM, SAED, EDX and XPS showed that VO2+ is covalently bonded to the silica surface. High selectivity and excellent conversion of various toluene derivatives, with less reactive aliphatic (sp3) C-H bonds, to related benzoic acids were quite noticeable. The aerobic oxygenation reaction of these alkylbenzenes was studied under the same conditions. All the results accompanied by sustainability of the inexpensive and simple magnetically separable heterogeneous catalyst proved the important criteria for commercial applications. This journal is
Mohammadpour, Pegah,Safaei, Elham
p. 23543 - 23553
(2020/07/14)

Light and oxygen-enabled sodium trifluoromethanesulfinate-mediated selective oxidation of C-H bonds
Visible light-induced organic reactions are important chemical transformations in organic chemistry, and their efficiency highly depends on suitable photocatalysts. However, the commonly used photocatalysts are precious transition-metal complexes and elaborate organic dyes, which hamper large-scale production due to high cost. Here, for the first time, we report a novel strategy: light and oxygen-enabled sodium trifluoromethanesulfinate-mediated selective oxidation of C-H bonds, allowing high-value-added aromatic ketones and carboxylic acids to be easily prepared in high-to-excellent yields using readily available alkyl arenes, methyl arenes and aldehydes as materials. The mechanistic investigations showed that the treatment of inexpensive and readily available sodium trifluoromethanesulfinate with oxygen under irradiation of light could in situ form a pentacoordinate sulfide intermediate as an efficient photosensitizer. The method represents a highly efficient, economical and environmentally friendly strategy, and the light and oxygen-enabled sodium trifluoromethanesulfinate photocatalytic system represents a breakthrough in photochemistry. This journal is
Fu, Hua,Liu, Can,Liu, Yong,Yang, Haijun,Zhu, Xianjin
supporting information
p. 4357 - 4363
(2020/07/14)

Photoinduced Carbon Tetrabromide Initiated Aerobic Oxidation of Substituted Toluenes to Carboxylic Acids
A mild and metal-free procedure is reported for the aerobic oxidation of substituted toluenes to carboxylic acids by using CBr 4 as initiator under irradiation from a 400 nm blue light-emitting diode.
Li, Xiaoqing,Xu, Xiangsheng,Yan, Xiaoyu,Yan, Xinhuan,Zhang, Guofu,Zheng, Kun
p. 272 - 274
(2020/02/18)

Oxidation of aromatic and aliphatic aldehydes to carboxylic acids by Geotrichum candidum aldehyde dehydrogenase
Oxidation reaction is one of the most important and indispensable organic reactions, so that green and sustainable catalysts for oxidation are necessary to be developed. Herein, biocatalytic oxidation of aldehydes was investigated, resulted in the synthesis of both aromatic and aliphatic carboxylic acids using a Geotrichum candidum aldehyde dehydrogenase (GcALDH). Moreover, selective oxidation of dialdehydes to aldehydic acids by GcALDH was also successful.
Hoshino, Tomoyasu,Yamabe, Emi,Hawari, Muhammad Arisyi,Tamura, Mayumi,Kanamaru, Shuji,Yoshida, Keisuke,Koesoema, Afifa Ayu,Matsuda, Tomoko
(2020/07/20)

Carbonylative Suzuki-Miyaura couplings of sterically hindered aryl halides: Synthesis of 2-aroylbenzoate derivatives
We have developed a carbonylative approach to the synthesis of diversely substituted 2-aroylbenzoate esters featuring a new protocol for the carbonylative coupling of aryl bromides with boronic acids and a new strategy to favour carbonylative over non-carbonylative reactions. Two different synthetic pathways-(i) the alkoxycarbonylation of 2-bromo benzophenones and (ii) the carbonylative Suzuki-Miyaura coupling of 2-bromobenzoate esters-were evaluated. The latter approach provided a broader substrate tolerance, and thus was the preferred pathway. We observed that 2-substituted aryl bromides were challenging substrates for carbonylative chemistry favouring the non-carbonylative pathway. However, we found that carbonylative Suzuki-Miyaura couplings can be improved by slow addition of the boronic acid, suppressing the unwanted direct Suzuki coupling and, thus increasing the yield of the carbonylative reaction.
Bayer, Annette,Ismael, Aya,Skrydstrup, Troels
supporting information
p. 1754 - 1759
(2020/03/17)

A sodium trifluoromethanesulfinate-mediated photocatalytic strategy for aerobic oxidation of alcohols
A sodium trifluoromethanesulfinate-mediated photocatalytic strategy for the aerobic oxidation of alcohols has been developed for the first time, and the photoredox aerobic oxidation of secondary and primary alcohols provided the corresponding ketones and carboxylic acids, respectively, in high to excellent yields.
Zhu, Xianjin,Liu, Can,Liu, Yong,Yang, Haijun,Fu, Hua
p. 12443 - 12446
(2020/10/30)

Synthesis method of benzoic acid compounds
The invention discloses a photocatalytic oxidation synthesis method of benzoic acid compounds, and the photocatalytic oxidation synthesis method comprises the following specific steps: mixing and dissolving toluene compounds and a catalyst in a solvent, reacting for 24-60h in the presence of an oxidant under the conditions of 350-460 nm LED illumination and a temperature of 20-80 DEG C, and performing post-treatment on the reaction liquid to obtain the benzoic acid compounds. The photocatalytic oxidation synthesis method has the advantages of no need of metal catalysts, simple operation and mild reaction conditions; oxygen is used as an oxidant, and the photocatalytic oxidation synthesis method has high atom economy, cheap reagent and environmental protection. The photocatalytic oxidationsynthesis method has good substrate applicability, and various substituents can realize the synthesis of corresponding benzoic acid compounds.
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Paragraph 0114; 0115; 0116; 0117

(2019/12/25)

Preparation methods of 2-bromo-3,6-dichlorobenzoic acid and dicamba
The invention provides a preparation method of dicamba. The preparation method comprises the following steps: S1), in the presence of a catalyst, 2-bromobenzoic acid is subjected to a chlorination reaction in chlorosulfonic acid or concentrated sulfuric acid, and 2-bromo-3,6-dichlorobenzoic acid is obtained; S2), 2-bromo-3,6-dichlorobenzoic acid is subjected to a methoxylation reaction, and dicamba is obtained. Compared with the prior art, 2-bromo-3,6-dichlorobenzoic acid is obtained from 2-bromobenzoic acid after the directional chlorination reaction, and dicamba can be obtained by the methoxylation reaction. The methods have the advantages of easily available raw materials, low comprehensive cost, high methoxylation reaction selectivity, high total yield, stable product quality and simple process, and facilitate industrial implementation.
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Paragraph 0039; 0040; 0043; 0044

(2019/06/05)

A transition metal free expedient approach for the C[dbnd]C bond cleavage of arylidene Meldrum's acid and malononitrile derivatives
A transition metal free expedient approach for the C[dbnd]C bond cleavage of electron deficient alkenes such as arylidene Meldrum's acid and malononitrile derivatives are discussed. The C[dbnd]C bond of these compound were cleaved to benzoic acid in good yield at high temperature. Most importantly, with oxone in CH3CN/H2O at 45 °C or m-CPBA in DCM or NaClO2 in THF/H2O or PIDA in THF at room temperature furnished benzaldehyde derivatives selectively in excellent yields.
Suresh, Muthiah,Kumari, Anusueya,Singh, Raj Bahadur
(2019/09/10)

Method for copper-catalyzed carboxylation reaction of arylboronic acid and carbon dioxide
The invention discloses a method for a copper-catalyzed carboxylation reaction of arylboronic acid and carbon dioxide. According to the method, carbon dioxide is used as a C1 source, copper catalysisis adopted, alkoxide serves as alkali, and a reaction is carried out in an organic solvent; the method is simple in process and easy to implement, and shows wide functional group compatibility; the method allows various arylboronic acids such as monosubstituted or polysubstituted phenylboronic acid, polycyclic aromatic hydrocarbon boronic acid and benzoheterocyclic boronic acid to be converted into corresponding arylcarboxylic acids with considerable yield under mild conditions; and the produced carboxylic acids have important application value, and can be used for deriving a great number of other common chemical substances, such as acyl halide, acid anhydride, ester and amide.
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Paragraph 0039; 0040

(2019/12/29)

CO2 activation by electrogenerated divalent samarium for aryl halide carboxylation
The reductive carboxylation of aryl halides has been investigated using a samarium electrode as a sacrificial anode to yield the corresponding benzoic acids, providing a smooth strategy for CO2 activation. Carboxylation occurred after an efficient reduction of carbon dioxide mediated by an electrogenerated Sm(ii)-complex acting as a strong monoelectronic reductive reagent.
Bazzi, Sakna,Le Duc, Ga?tan,Schulz, Emmanuelle,Gosmini, Corinne,Mellah, Mohamed
supporting information
p. 8546 - 8550
(2019/10/02)

Amine compound for inhibiting SSASASASASASASAO/VAP-1 and application thereof in medicine (by machine translation)
The invention relates to an amine compound serving as an amino urea-sensitive amine oxidase (SSASAO) and/or a vascular adhesion protein -1 (VAP AP AP-1) inhibitor and application thereof in medicine, and further relates to a pharmaceutical composition containing the compound. The compounds or pharmaceutical compositions described herein may be used to treat inflammation and/or inflammation related diseases, diabetes and/or diabetes-related diseases, psychiatric disorders, ischemic diseases, vascular diseases, fibrosis or tissue transplant rejection. (by machine translation)
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Paragraph 0426; 0428-0429

(2019/08/12)

Solvent-free mechanochemical oxidation and reduction of biomass-derived 5-hydroxymethyl furfural
The simultaneous synthesis of 5-hydroxymethyl-2-furoic acid and 2,5-hydroxymethylfuran from biomass-derived 5-hydroxymethyl furan was developed using a solvent-free mechanochemical approach. The results obtained for the Cannizzaro disproportionation reaction show quantitative conversions of the starting materials with reaction times of only 5 min. Employing solvent-free conditions allows for a more sustainable synthetic approach that is reflected in an Efactor 7 times smaller than that in previous reports. Additionally, initial results of the use of a sacrificial reagent, with the same solvent-free mechanochemical approach, for the selective reduction and oxidation of HMF are presented.
Chacón-Huete,Messina,Chen,Cuccia,Ottenwaelder,Forgione
p. 5261 - 5265
(2018/12/05)

A biocatalytic method for the chemoselective aerobic oxidation of aldehydes to carboxylic acids
Herein, we present a study on the oxidation of aldehydes to carboxylic acids using three recombinant aldehyde dehydrogenases (ALDHs). The ALDHs were used in purified form with a nicotinamide oxidase (NOx), which recycles the catalytic NAD+ at the expense of dioxygen (air at atmospheric pressure). The reaction was studied also with lyophilised whole cell as well as resting cell biocatalysts for more convenient practical application. The optimised biocatalytic oxidation runs in phosphate buffer at pH 8.5 and at 40 °C. From a set of sixty-one aliphatic, aryl-Aliphatic, benzylic, hetero-Aromatic and bicyclic aldehydes, fifty were converted with elevated yield (up to >99%). The exceptions were a few ortho-substituted benzaldehydes, bicyclic heteroaromatic aldehydes and 2-phenylpropanal. In all cases, the expected carboxylic acid was shown to be the only product (>99% chemoselectivity). Other oxidisable functionalities within the same molecule (e.g. hydroxyl, alkene, and heteroaromatic nitrogen or sulphur atoms) remained untouched. The reaction was scaled for the oxidation of 5-(hydroxymethyl)furfural (2 g), a bio-based starting material, to afford 5-(hydroxymethyl)furoic acid in 61% isolated yield. The new biocatalytic method avoids the use of toxic or unsafe oxidants, strong acids or bases, or undesired solvents. It shows applicability across a wide range of substrates, and retains perfect chemoselectivity. Alternative oxidisable groups were not converted, and other classical side-reactions (e.g. halogenation of unsaturated functionalities, Dakin-Type oxidation) did not occur. In comparison to other established enzymatic methods such as the use of oxidases (where the concomitant oxidation of alcohols and aldehydes is common), ALDHs offer greatly improved selectivity.
Knaus, Tanja,Tseliou, Vasilis,Humphreys, Luke D.,Scrutton, Nigel S.,Mutti, Francesco G.
supporting information
p. 3931 - 3943
(2018/09/11)

Catalytic Promiscuity of Galactose Oxidase: A Mild Synthesis of Nitriles from Alcohols, Air, and Ammonia
We report an unprecedented catalytically promiscuous activity of the copper-dependent enzyme galactose oxidase. The enzyme catalyses the one-pot conversion of alcohols into the related nitriles under mild reaction conditions in ammonium buffer, consuming ammonia as the source of nitrogen and dioxygen (from air at atmospheric pressure) as the only oxidant. Thus, this green method does not require either cyanide salts, toxic metals, or undesired oxidants in stoichiometric amounts. The substrate scope of the reaction includes benzyl and cinnamyl alcohols as well as 4- and 3-pyridylmethanol, giving access to valuable chemical compounds. The oxidation proceeds through oxidation from alcohol to aldehyde, in situ imine formation, and final direct oxidation to nitrile.
Vilím, Jan,Knaus, Tanja,Mutti, Francesco G.
supporting information
p. 14240 - 14244
(2018/10/15)

Ag-nanoparticle embedded p(AA) hydrogel as an efficient green heterogeneous Nano-catalyst for oxidation and reduction of organic compounds
P(AA)-Ag heterogeneous catalyst system comprised of Ag nanoparticles embedded within hydrogel matrices has been described for the selective aerobic oxidation of alcohols and reduction of nitro phenols in water. P(AA)-Ag nanocomposite was characterized by Fourier transform infrared (FT-IR), scanning electron microscopy (SEM), transmission electron microscopy (TEM), thermal gravimetric analysis (TGA), X-Ray photoelectron spectroscopy (XPS) and inductively coupled plasma atomic emission spectrometer (ICP). Catalytic activity of p(AA)-Ag catalyst was investigated in the aerobic oxidation of primary alcohols and reduction of nitro compounds by emphasizing the effect of different parameters such as temperature, catalyst amount, substituent effect, etc. The catalyst was easily recovered from the reaction medium and it could be re-used for other three runs without significant loss of activity.
Ghorbanloo, Massomeh,Heydari, Ali,Yahiro, Hidenori
(2017/10/06)

TBHP/ n -Bu 4 PBr-Promoted Oxidative Cross-Dehydrogenative Coupling of Aryl Methanols: A Facile Synthesis of Symmetrical Carboxylic Anhydride Derivatives
A transition-metal-free oxidative cross-dehydrogenative coupling reaction has been developed for the preparation of symmetrical carboxylic anhydrides through self-coupling dual C-O bond formations of aryl methanols. In the presence of a catalytic amount of tetrabutylphosphonium bromide (TBPB) as transfer agent and aqueous tert -butyl hydroperoxide (TBHP) as oxidant and reactant, methylene groups of aryl methanols were efficiently oxidized to C=O and coupled with the peroxide oxygen from TBHP to form a diverse array of symmetrical carboxylic anhydride derivatives.
Adib, Mehdi,Pashazadeh, Rahim
supporting information
p. 136 - 140
(2017/12/27)

Acceptorless and Base-free Dehydrogenation of Cyanohydrin with (η6-Arene)halide(Bidentate Phosphine)ruthenium(II) Complex
Ruthenium-catalyzed dehydrogenation of cyanohydrins under acceptorless and base-free conditions was demonstrated for the first time in the synthesis of acyl cyanide. As opposed to the thermodynamically preferred elimination of hydrogen cyanide, the dehydrogenation of cyanohydrins could be kinetically controlled with ruthenium (II) bidentate phosphine complexes. The effects of the arene, phosphine ligands and counter anions were investigated in regard to catalytic activity and selectivity. Selective dehydrogenation can occur via β-hydride elimination with the experimentally observed [(alkoxide)Ru] complex. (Figure presented.).
Kim, Kicheol,Moeljadi, Adhitya Mangala Putra,Hirao, Hajime,Hong, Soon Hyeok
supporting information
p. 3292 - 3298
(2017/09/06)

Bimane: A Visible Light Induced Fluorescent Photoremovable Protecting Group for the Single and Dual Release of Carboxylic and Amino Acids
A series of ester conjugates of carboxylic and amino acids were synthesized based on bimane fluorescent photoremovable protecting group (FPRPG). The photorelease of single and dual (same as well as different) carboxylic and amino acids is demonstrated from a single bimane molecule on irradiation with visible light (λ ≥ 410 nm). The detailed mechanistic study of photorelease revealed that the release of two caged acids is simultaneous but in a stepwise pathway.
Chaudhuri, Amrita,Venkatesh, Yarra,Behara, Krishna Kalyani,Singh, N. D. Pradeep
supporting information
p. 1598 - 1601
(2017/04/13)

Harnessing the Reactivity of Iridium Hydrides by Air: Iridium-Catalyzed Oxidation of Aldehydes to Acids in Water
An iridium-catalyzed oxidation of aldehydes to acids was realized by using air as the oxidant and water as the solvent in the presence of base. Interestingly, the same type of catalysts were also used for the reduction of aldehydes under acidic conditions. A common iridium hydride intermediate is proposed for both redox reactions. The oxidation has a number of advantages such as high yields, great functionality tolerance, and easy purification without chromatography.
Yang, Zhanhui,Luo, Renshi,Zhu, Zhongpeng,Yang, Xuerong,Tang, Weiping
supporting information
p. 4095 - 4098
(2017/11/21)

Formation, Oxidation, and Fate of the Breslow Intermediate in the N-Heterocyclic Carbene-Catalyzed Aerobic Oxidation of Aldehydes
The reaction paths and intermediate structures related to the formation of the Breslow intermediate and its oxidation along the oxidative/oxygenative lanes have been studied from a mechanistic point of view, with the support of gas-phase and computational studies. The results confirm the occurrence of a single-electron transfer from the Breslow intermediate to the molecular oxygen with formation of a radical couple that recombines either as a peroxide anion 7′ to afford the aldehyde-to-carboxylic acid product or as a hydroperoxy derivative 7″ that evolved into an electrophilic acyl azolium, opening to the aldehyde-to-ester conversion. Steric factors enter into determining the different reactivity. All of the intermediates of both catalytic paths have been observed and characterized under mass spectrometric conditions. In particular, for the imidazoline catalyst, the (+)ESI-MS/(MS) detection of the genuine Breslow intermediate was made possible in virtue of its limited reactivity. Mechanistic aspects of the N-heterocyclic carbenes catalyzed aerobic oxidation of aldehydes shares important similarities with that one of the recently revisited benzoin condensation.
Bortolini, Olga,Chiappe, Cinzia,Fogagnolo, Marco,Massi, Alessandro,Pomelli, Christian Silvio
p. 302 - 312
(2017/04/26)

SO2F2-Mediated One-Pot Synthesis of Aryl Carboxylic Acids and Esters from Phenols through a Pd-Catalyzed Insertion of Carbon Monoxide
A one-pot Pd-catalyzed carbonylation of phenols into their corresponding aryl carboxylic acids and esters through the insertion of carbon monoxide has been developed. This procedure offers a direct synthesis of aryl carboxylic acids and esters from inexpensive and abundant starting materials (phenols, SO2F2 and CO) under mild conditions. This method tolerates a broad range of functional groups and is also applicable for the modification of complicated natural products.
Fang, Wan-Yin,Leng, Jing,Qin, Hua-Li
supporting information
p. 2323 - 2331
(2017/09/06)

Oxalic acid as the: In situ carbon monoxide generator in palladium-catalyzed hydroxycarbonylation of arylhalides
An efficient palladium-catalyzed hydroxycarbonylation reaction of arylhalides using oxalic acid as a CO source has been developed. The reaction features high safety, low catalyst loading, and a broad substrate scope, and provides a safe and tractable approach to access a variety of aromatic carboxylic acid compounds. Mechanistic studies revealed the decomposition pattern of oxalic acid.
Shao, Changdong,Lu, Ailan,Wang, Xiaoling,Zhou, Bo,Guan, Xiaohong,Zhang, Yanghui
supporting information
p. 5033 - 5040
(2017/07/10)

Dithioester-enabled chemodivergent synthesis of acids, amides and isothiazoles via C[sbnd]C bond cleavage and C[sbnd]O/C[sbnd]N/C[sbnd]S bond formations under metal- and catalyst-free conditions
An operationally simple and user-friendly process to access privileged scaffolds such as acids, amides and isothiazoles has been devised employing β-ketodithioesters for the first time. Remarkably, the new protocol involves combination of C[sbnd]C bond cl
Soni, Sonam,Koley, Suvajit,Singh, Maya Shankar
supporting information
p. 2512 - 2516
(2017/05/31)

Iodine-catalyzed oxidative C-C bond cleavage for benzoic acids and benzamides from alkyl aryl ketones
Iodine-catalyzed oxidative C-C bond cleavage has been performed for the facile synthesis of both benzoic acids and benzamides from readily available alkyl aryl ketones. Additionally benzylidene acetones and phenylacetylenes were also converted to the corresponding aromatic acids under the same conditions. This approach features the use of inexpensive iodine as a catalyst, broad substrate scope and open air conditions.
Sathyanarayana, Pochampalli,Upare, Atul,Ravi, Owk,Muktapuram, Prathap Reddy,Bathula, Surendar Reddy
p. 22749 - 22753
(2016/03/15)

Nickel-catalyzed ortho-halogenation of unactivated (hetero)aryl C-H bonds with lithium halides using a removable auxiliary
The first example of Ni-catalyzed halogenation of (hetero)aryl C-H bonds with lithium halides (LiX, X = Br, I, Cl) using PIP as a removable directing group is reported. This protocol provides an efficient access to ortho-halogenated (hetero)arenes with operational simplicity, good functional group tolerance, and large-scale synthesis.
Zhan, Bei-Bei,Liu, Yan-Hua,Hu, Fang,Shi, Bing-Feng
p. 4934 - 4937
(2016/04/10)

Bridging C?H Activation: Mild and Versatile Cleavage of the 8-Aminoquinoline Directing Group
8-Aminoquinoline has emerged as one of the most powerful bidentate directing groups in history of C?H activation within the last decade. However, cleavage of its robust amide bond has shown to be challenging in several cases, thus jeopardizing the general synthetic utility of the method. To overcome this limitation, we herein report a simple oxidative deprotection protocol. This transformation rapidly converts the robust amide to a labile imide, allowing subsequent cleavage in a simple one-pot fashion to rapidly access carboxylic acids or amides as final products.
Berger, Martin,Chauhan, Rajan,Rodrigues, Catarina A. B.,Maulide, Nuno
supporting information
p. 16805 - 16808
(2016/11/16)

Combined production method for substituted benzaldehyde, substituted benzyl alcohol and substituted benzoic acid
The invention discloses a combined production method for substituted benzaldehyde, substituted benzyl alcohol and substituted benzoic acid. The method comprises the following steps: (1) oxidation: a step of continuously introducing substituted toluene, a catalyst and oxygen-contained gas into an oxidation reactor and carrying out reaction so as to obtain oxidation reaction liquid; (2) hydrolyzation: a step of allowing the oxidation reaction liquid to continuously enter a hydrolysis reactor, and continuously adding water into the hydrolysis reactor and carrying out reaction so as to obtain a hydrolysis reaction mixture; (3) liquid-liquid layering: a step of layering the hydrolysis reaction mixture so as to obtain an oil phase and an aqueous phase; and (4) separation of products: a step of subjecting the oil phase to distillation so as to respectively obtain incompletely-reacted substituted toluene, substituted benzyl alcohol and substituted benzaldehyde, and subjecting the aqueous phase to cooling, crystallizing and filtering so as to obtain filtrate and substituted benzoic acid. The combined production method provided by the invention has the advantages of high raw material conversion rate, few by-products, good selectivity of target products, greenness and environmental protection.
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Paragraph 0087; 0088

(2017/01/31)

[Ru(bpy)3]Cl2-catalyzed aerobic oxidative cleavage β-diketones to carboxylic acids under visible light irradiation
A mild and highly efficient method for the preparation of carboxylic acids is developed through a visible-light-mediated aerobic oxidative cleavage of β-diketones. This process provides a potential general, practical and scalable protocol for both laboratory synthesis and industrial production of carboxylic acids in a green manner.
Wang, Xiao-Yan,Shang, Zhen-Peng,Zha, Gao-Feng,Chen, Xiao-Qing,Bukhari, Syed Nasir Abbas,Qin, Hua-Li
supporting information
p. 5628 - 5631
(2016/11/23)

Flow carbonylation of sterically hindered ortho-substituted iodoarenes
The flow synthesis of ortho-substituted carboxylic acids, using carbon monoxide gas, has been studied for a number of substrates. The optimised conditions make use of a simple catalyst system compromising of triphenylphosphine as the ligand and palladium acetate as the pre-catalyst. Carbon monoxide was introduced via a reverse "tube-in-tube" flow reactor at elevated pressures to give yields of carboxylated products that are much higher than those obtained under normal batch conditions.
Mallia, Carl J.,Walter, Gary C.,Baxendale, Ian R.
supporting information
p. 1503 - 1511
(2016/08/02)

Copper-catalyzed ortho-halogenation of arenes and heteroarenes directed by a removable auxiliary
Copper-catalyzed ortho-halogenation of C(sp2)-H bonds directed by a PIP directing group with NXS (X = Cl, Br, I) has been developed. The reaction is scalable and tolerates a broad range of functional groups and heteroarenes, providing an efficient access to halogenated arenes and heteroarenes.
Li, Bo,Liu, Bin,Shi, Bing-Feng
p. 5093 - 5096
(2015/03/30)

Iron oxalate capped iron-copper nanomaterial for oxidative transformation of aldehydes
An efficient, sustainable and green procedure for the synthesis of selective orthorhombic iron(oxalate) capped Fe-Cu bimetallic oxide nanomaterial [Fe(ox)Fe-CuOx] was developed using a sodium borohydride reduction of iron(ii) salt in the presence of oxalic acid at room temperature followed by addition of copper sulfate in water. The reported method is a cost-effective chemical route for producing [Fe(ox)Fe-CuOx] nano material at the gram level with a surface area of 78.4 m2 g-1 and a pore volume of 0.141 cm3 g-1. The [Fe(ox)Fe-CuOx] nanomaterials were found to be useful as a recoverable catalyst for the oxidative transformation of an aldehyde to its corresponding ester and acid in presence of hydrogen peroxide.
Kashyap, Rajarshi,Talukdar, Dhruba Joyti,Pratihar, Sanjay
p. 1430 - 1437
(2015/02/19)

A Metal-Free Approach to Carboxylic Acids by Oxidation of Alkyl, Aryl, or Heteroaryl Alkyl Ketones or Arylalkynes
The metal-free oxidation of dialkyl, alkyl aryl, or alkyl heteroaryl ketones or arylalkynes to the corresponding carboxylic acids is achieved using an oxidative mixture of Oxone and trifluoroacetic acid. This green method is a simple and mild protocol to obtain carboxylic derivatives in excellent yields.
Aravinda Kumar,Venkateswarlu, Vunnam,Vishwakarma, Ram A.,Sawant, Sanghapal D.
p. 3161 - 3168
(2015/10/19)

DMSO/I2 mediated C-C bond cleavage of α-ketoaldehydes followed by C-O bond formation: A metal-free approach for one-pot esterification
A novel and efficient I2/DMSO mediated metal-free strategy is presented for the direct C-C bond cleavage of aryl-/heteroaryl- or aliphatic α-ketoaldehydes by C2-decarbonylation and C1-carbonyl oxidation to give the corresponding carboxylic acids followed by esterification in one pot, offering excellent yields in both the steps. Here, DMSO acts as the oxygen source/oxidant and this reaction works very well under both conventional heating and microwave irradiation. This is a very simple and convenient protocol.
Venkateswarlu, Vunnam,Aravinda Kumar,Gupta, Sorav,Singh, Deepika,Vishwakarma, Ram A.,Sawant, Sanghapal D.
supporting information
p. 7973 - 7978
(2015/07/27)

Ligand-Free Palladium-Catalyzed Hydroxycarbonylation of Aryl Halides under Ambient Conditions: Synthesis of Aromatic Carboxylic Acids and Aromatic Esters
Aryl halides were readily converted into their corresponding aromatic carboxylic acids in high yields with high selectivity by ligand-free palladium-catalyzed hydroxycarbonylation at room temperature and atmospheric pressure. The new method is operationally simple and scalable. In addition, aromatic esters were easily synthesized through one-pot hydroxycarbonylation/alkylation with alkyl halides.
Han, Wei,Jin, Fengli,Zhou, Qing
p. 1861 - 1868
(2015/06/30)

Oxidative cleavage of olefins by in situ-generated catalytic 3,4,5,6-tetramethyl-2-iodoxybenzoic acid/oxone
Oxidative cleavage of a variety of olefins to the corresponding ketones/carboxylic acids is shown to occur in a facile manner with 3,4,5,6-tetramethyl-2-iodobenzoic acid (TetMe-IA)/oxone. The simple methodology involves mere stirring of the olefin and catalytic amount (10 mol %) of TetMe-IA and oxone in acetonitrile-water mixture (1:1, v/v) at rt. The reaction mechanism involves initial dihydroxylation of the olefin with oxone, oxidative cleavage by the in situ-generated 3,4,5,6-tetramethyl-2-iodoxybenzoic acid (TetMe-IBX), and oxidation of the aldehyde functionality to the corresponding acid with oxone. Differences in the reactivities of electron-rich and electron-poor double bonds have been exploited to demonstrate chemoselective oxidative cleavage in substrates containing two double bonds.
Moorthy, Jarugu Narasimha,Parida, Keshaba Nanda
p. 11431 - 11439
(2015/02/05)

An insight into the mechanism of the aerobic oxidation of aldehydes catalyzed by N-heterocyclic carbenes
N-Heterocyclic carbene catalysis for the aerobic oxidation and esterification of aromatic aldehydes was monitored by ESI-MS (MS/MS) and the key intermediates were intercepted and characterized using the charge-tag strategy.
Bortolini,Chiappe,Fogagnolo,Giovannini,Massi,Pomelli,Ragno
supporting information
p. 2008 - 2011
(2014/03/21)

Electrophilicity and nucleophilicity of commonly used aldehydes
The present approach for determining the electrophilicity (E) and nucleophilicity (N) of aldehydes includes a kinetic study of KMNO4 oxidation and NaBH4 reduction of aldehydes. A transition state analysis of the KMNO4 promoted aldehyde oxidation reaction has been performed, which shows a very good correlation with experimental results. The validity of the experimental method has been tested using the experimental activation parameters of the two reactions. The utility of the present approach is further demonstrated by the theoretical versus experimental relationship, which provides easy access to E and N values for various aldehydes and offers an at-a-glance assessment of the chemical reactivity of aldehydes in various reactions. the Partner Organisations 2014.
Pratihar, Sanjay
p. 5781 - 5788
(2014/07/22)

Oxidation cascade with oxone: Cleavage of olefins to carboxylic acids
A variety of olefins is shown to be cleaved oxidatively to the corresponding acids with oxone as the reagent. The simple methodology that works well for a range of alkenes, i.e., styrenes, nitrostyrenes, stilbenes, cinnamic acids, chalcones, etc., involves heating of the reactant with oxone in acetonitrile-water mixture (1:1, v/v) at reflux. The oxidation cascade involves initial dihydroxylation followed by oxidative cleavage and oxidation of the resultant aldehydes to acids.
Parida, Keshaba Nanda,Moorthy, Jarugu Narasimha
p. 2280 - 2285
(2014/03/21)

TEMPO-mediated oxidation of primary alcohols to aldehydes under visible light and air
A homogeneous visible light photoredox TEMPO-mediated selective oxidation of primary alcohols to the corresponding carbonyl compounds was developed using molecular oxygen from air as the terminal oxidant. Ru(bpy)3(PF 6)2 (bpy: bipyridyl) and Ir(dtb-bpy)(ppy) 2(PF6) (dtb-bpy: 4,4′-di-tert-butyl-2,2′- bipyridyl; ppy: 2-phenylpyridine) were used as the sensitizers. A homogeneous visible light photoredox TEMPO-mediated selective oxidation of primary alcohols to the corresponding carbonyl compounds was developed. Molecular oxygen from air was the terminal oxidant. Copyright
Liu, Dongwang,Zhou, Hongxia,Gu, Xiangyong,Shen, Xiaoqin,Li, Pixu
supporting information
p. 117 - 122
(2014/03/21)

Catalytic bio-chemo and bio-bio tandem oxidation reactions for amide and carboxylic acid synthesis
A catalytic toolbox for three different water-based one-pot cascades to convert aryl alcohols to amides and acids and cyclic amines to lactams, involving combination of oxidative enzymes (monoamine oxidase, xanthine dehydrogenase, galactose oxidase and laccase) and chemical oxidants (TBHP or CuI(cat)/H2O2) at mild temperatures, is presented. Mutually compatible conditions were found to afford products in good to excellent yields. This journal is
Bechi, Beatrice,Herter, Susanne,McKenna, Shane,Riley, Christopher,Leimkühler, Silke,Turner, Nicholas J.,Carnell, Andrew J.
supporting information
p. 4524 - 4529
(2014/12/11)

Efficient method for the oxidation of aldehydes and diols with tert-butylhydroperoxide under transition metal-free conditions
An efficient, mild, and simple protocol is presented for the oxidation of aldehydes and diols to carboxylic acids utilizing 70% aq TBHP as oxidant and t-BuOK as additive. The oxidation of aldehydes could be achieved by two methods under aqueous medium. Excellent yields of products were obtained in short reaction times. Notably, the products were isolated by simple filtration technique and do not involve chromatographic separation. These reactions may prove to be valuable alternatives to traditional metal-mediated oxidations. Oxidation does not require any transition metals or organic solvents in reaction, making this protocol green.
Shaikh, Tanveer Mahammadali,Hong, Fung-E
p. 8929 - 8935
(2013/09/23)