cas 445-29-4, 2-Fluorobenzoic acid | Articles data

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Photo-induced deep aerobic oxidation of alkyl aromatics
Oxidation is a major chemical process to produce oxygenated chemicals in both nature and the chemical industry. Presently, the industrial manufacture of benzoic acids and benzene polycarboxylic acids (BPCAs) is mainly based on the deep oxidation of polyalkyl benzene, which is somewhat suffering from environmental and economical disadvantage due to the formation of ozone-depleting MeBr and corrosion hazards of production equipment. In this report, photo-induced deep aerobic oxidation of (poly)alkyl benzene to benzene (poly)carboxylic acids was developed. CeCl3 was proved to be an efficient HAT (hydrogen atom transfer) catalyst in the presence of alcohol as both hydrogen and electron shuttle. Dioxygen (O2) was found as a sole terminal oxidant. In most cases, pure products were easily isolated by simple filtration, implying large-scale implementation advantages. The reaction provides an ideal protocol to produce valuable fine chemicals from naturally abundant petroleum feedstocks. [Figure not available: see fulltext.].
Wang, Chang-Cheng,Zhang, Guo-Xiang,Zuo, Zhi-Wei,Zeng, Rong,Zhai, Dan-Dan,Liu, Feng,Shi, Zhang-Jie
p. 1487 - 1492
(2021/07/10)

Milled Dry Ice as a C1 Source for the Carboxylation of Aryl Halides
The use of carbon dioxide as a C1 chemical feedstock remains an active field of research. Here we showcase the use of milled dry ice as a method to promote the availability of CO 2in a reaction solution, permitting practical synthesis of arylcarboxylic acids. Notably, the use of milled dry ice produces marked increases in yields relative to those obtained with gaseous CO 2, as previously reported in the literature.
O'Brien, Connor J.,Nicewicz, David A.
supporting information
p. 814 - 816
(2021/03/01)

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)

Oxidative α-C-C Bond Cleavage of 2° and 3° Alcohols to Aromatic Acids with O2at Room Temperature via Iron Photocatalysis
The selective α-C-C bond cleavage of unfunctionalized secondary (2°) and tertiary alcohols (3°) is essential for valorization of macromolecules and biopolymers. We developed a blue-light-driven iron catalysis for aerobic oxidation of 2° and 3° alcohols to acids via α-C-C bond cleavages at room temperature. The first example of oxygenation of the simple tertiary alcohols was reported. The iron catalyst and blue light play critical roles to enable the formation of highly reactive O radicals from alcohols and the consequent two α-C-C bond cleavages.
Zhang, Zongnan,Zhang, Guoxiang,Xiong, Ni,Xue, Ting,Zhang, Junjie,Bai, Lu,Guo, Qinyue,Zeng, Rong
supporting information
p. 2915 - 2920
(2021/05/05)

Atomically Dispersed Co Clusters Anchored on N-doped Carbon Nanotubes for Efficient Dehydrogenation of Alcohols and Subsequent Conversion to Carboxylic Acids
The catalytic dehydrogenation of readily available alcohols to high value-added carbonyl compounds is a research hotspot with scientific significance. Most of the current research about this reaction is performed with noble metal-based homogeneous catalysts of high price and poor reusability. Herein, highly dispersed Co-cluster-decorated N-doped carbon nanotubes (Co/N-CNTs) were fabricated via a facile strategy and used for the dehydrogenation of alcohols with high efficiency. Various characterization techniques confirmed the presence of metallic Co clusters with almost atomic dispersion, and the N-doped carbon supports also enhanced the catalytic activity of Co clusters in the dehydrogenation reaction. Aldehydes as dehydrogenation products were further transformed in situ to carboxylic acids through a Cannizzaro-type pathway under alkaline conditions. The reaction pathway of the dehydrogenation of alcohols was clearly confirmed by theoretical calculations. This work should provide an effective and simple approach for the accurate design and synthesis of small Co-clusters catalysts for the efficient dehydrogenation-based transformation of alcohols to carboxylic acids under mild reaction conditions.
Dong, Zhengping,Fang, Jian,Li, Boyang,Xu, Dan,Zhang, Fengwei,Zhao, Hong,Zhu, Hanghang
p. 4536 - 4545
(2021/09/22)

Pd(OAc)2 promoted bis-N-heterocyclic carbene-catalyzed oxidative transformation of aldehydes
The bis-N-heterocyclic carbene-catalyzed (bis-NHC-catalyzed) oxidative transformation of aldehydes was successfully studied in water under air. The reaction rate increased through the use of Pd(OAc)2 as an additive. Notably, the catalytic system exhibited good tolerance toward aliphatic and aromatic aldehydes bearing halide and alkyl functional groups. In addition, gram-scale reaction was also tested in this study. The use of water and operational simplicity make this methodology environmentally benign and cost-effective.
Yu, Ya-Han,Wang, Tsui,Chiu, Chien-Cheng,Lu, Ta-Jung,Lee, Dong-Sheng
p. 202 - 205
(2019/11/28)

Preparation method of bimetallic catalyst oxidation aldehyde synthetic carboxylic acid (by machine translation)
The method is, in a reaction solvent: under normal pressure oxygen condition, under the action of a bimetallic catalyst under the action of a bimetallic catalyst under the action of a bimetallic catalyst under the action of a bimetallic catalyst, at, DEG, under stirring . under a stirring condition with an aldehyde compound as a substrate 10-90 °C in a reaction solvent under, a stirring condition under the action of a bimetallic catalyst . The reaction solution is stirred, for. 1-12h, hours at; room temperature, under, the action, of a bimetallic 1:1 catalyst Cu(OAc) under the action of a bimetallic catalyst under the action of a bimetallic catalyst under the action of a double-metal catalyst. 2 · H2 O And Co(OAc)2 · 44H2 O As the bimetallic catalyst, can achieve the highest yield of the carboxylic acid product, in high yield, by adjusting the reaction temperature, solvent, catalyst amount, for different types of the raw material aldehyde 98%. (by machine translation)
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Paragraph 0030-0031

(2020/05/30)

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)

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)

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 0130; 0131; 0132; 0133

(2019/12/25)

Nickel-catalyzed carboxylation of aryl and heteroaryl fluorosulfates using carbon dioxide
The development of efficient and practical methods to construct carboxylic acids using CO2 as a C1 synthon is of great importance. Nickel-catalyzed carboxylation of aryl fluorosulfates and heteroaryl fluorosulfates with CO2 is described, affording arene carboxylic acids with good to excellent yields under mild conditions. In addition, a one-pot phenol fluorosulfation/carboxylation is developed.
Ma, Cong,Zhao, Chuan-Qi,Xu, Xue-Tao,Li, Zhao-Ming,Wang, Xiang-Yang,Zhang, Kun,Mei, Tian-Sheng
p. 2464 - 2467
(2019/04/10)

Dry Chemistry of Ferrate(VI): A Solvent-Free Mechanochemical Way for Versatile Green Oxidation
The +6 oxidation state of iron generally exists in the form of ferrate(VI) with high redox potential and environmentally friendly nature. Although ferrate(VI) has been known for over a century, its chemistry is still limited to the solvent-based reactions that suffers from the insolubility/instability of this oxidant and the environmental issues caused by hazardous solvents. Herein, we explore the solvent-free reactivity of ferrate(VI) under mechanical milling, revealing that its strong oxidizing power is accessible in the “dry” solid state towards a broad variety of substrates, for example, aromatic alcohols/aldehydes and carbon nanotubes. More significantly, solvent-free mechanochemistry also reshapes the oxidizing ability of ferrate(VI) due to the underlying solvent-free effect and the promotive mechanical actions. This study opens up a new chemistry of ferrate(VI) with promising application in green oxidative transformation of both organic and inorganic substrates.
Zhang, Zhao-Yang,Ji, Deyang,Mao, Wenting,Cui, Yu,Wang, Qing,Han, Lu,Zhong, Hongliang,Wei, Zhongming,Zhao, Yixin,N?rgaard, Kasper,Li, Tao
supporting information
p. 10949 - 10953
(2018/08/01)

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)

Tandem one-pot CO2 reduction by PMHS and silyloxycarbonylation of aryl/vinyl halides to access carboxylic acids
The present study discloses the synthesis of aryl/vinyl carboxylic acids from Csp2-bound halides (Cl, Br, I) in a carbonylative path by using silyl formate (from CO2 and hydrosilane) as an instant CO-surrogate. Hydrosilane provides hydride for reduction and its oxidation product silanol serves as a coupling partner. Mono-, di-, and tri-carboxylic acids were obtained from the corresponding aryl/vinyl halides.
Paridala, Kumaraswamy,Lu, Sheng-Mei,Wang, Meng-Meng,Li, Can
supporting information
p. 11574 - 11577
(2018/10/31)

Application of metallide/palladium compound catalytic reduction system in reaction of removing allyl groups and deuteration reaction
The invention discloses application of a metallide/palladium compound catalytic reduction system in reaction of removing allyl groups of a compound containing the allyl groups and deuteration reaction. The reaction comprises the following steps: under protection of nitrogen gas, suspending a palladium compound and a metallide in a solvent, stirring for 5 minutes, adding the compound containing theallyl groups, reacting for 0.5-36 hours at the temperature of minus 50-120 DEG C, adding ice water to stop reaction, regulating a pH value to 3.5 by using diluted hydrochloric acid, and carrying outsolvent extraction, drying by steaming and column-chromatography purification on reaction liquid to finish the reaction.
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Paragraph 0043

(2018/07/30)

Pd-Catalyzed debenzylation and deallylation of ethers and esters with sodium hydride
Herein we demonstrate simply that the addition of Pd(OAc)2 as a promotor switches the reactivity of a commonly used base NaH to a nucleophilic reductant. The reactivity is engineered into a palladium-catalyzed reductive debenzylation and deallylation of aryl ethers and esters. This operationally simple, mild protocol displays a broad substrate scope and a broad spectrum of functional group tolerance (>50 examples) and high chemoselectivity toward aryl ethers over aliphatic structures. Moreover, the dual reactivity of NaH as a base and a reductant is demonstrated in efficient synthetic elaboration.
Mao, Yujian,Liu, Ye,Hu, Yanwei,Wang, Liang,Zhang, Shilei,Wang, Wei
p. 3016 - 3020
(2018/04/14)

Sodium copper chlorophyllin catalyzed chemoselective oxidation of benzylic alcohols and diarylmethanes in water
We report the highly efficient and chemoselective oxidation of benzylic alcohols catalyzed by sodium copper chlorophyllin in water, producing corresponding arylcarbonyl compounds. Importantly, the catalytic system exhibits a wide substrate scope and high functional group tolerance. Moreover, secondary alcohols and even diarylmethanes were smoothly oxidized to the desired aryl ketones with excellent yields.
Liu, Shi-juan,Zhang, Miao,Lu, Rong,Li, Xiu-ying,Che, Guang-bo
(2018/08/17)

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)

Regiospecific ortho-C?H Allylation of Benzoic Acids
A carboxylate-directed ortho-C?H functionalization has been developed and it allows the regiospecific introduction of allyl residues to benzoic acids. In the presence of a [Ru(p-cymene)Cl2]2 and K3PO4, benzoic acids react with allyl acetates at only 50 °C to give the corresponding ortho-allylbenzoic acids. The protocol is generally applicable to both electron-rich and electron-poor benzoic acids in combination with linear and branched allyl acetates. The products can be further functionalized in situ, for example, by double-bond migration, lactonization, or decarboxylation.
Trita, A. Stefania,Biafora, Agostino,Pichette Drapeau, Martin,Weber, Philip,Goo?en, Lukas J.
supporting information
p. 14580 - 14584
(2018/03/13)

Synthesis of an oligomer ruthenium complex and its catalysis in the oxidation of alcohols
A ligand with both a terpyridine and a pyridine-2,6-dicarboxylate group (abbreviated as terpy-pydic) was designed and synthesized. This ligand reacted with [Ru(p-cymene)Cl2]2 to afford a novel oligomer ruthenium complex named as oligomer-Ru(terpy)(pydic) which was characterized thoroughly. Under the catalysis of this oligomer ruthenium complex, different sorts of secondary alcohols were oxidized to the corresponding kenones by the oxidant tert-butyl hydroperoxide. Besides, this catalyst can be readily recovered and recycled several times without a large loss of its efficiency.
Zhang, Yuecheng,Huo, Wenge,Zhang, Hong-Yu,Zhao, Jiquan
p. 47261 - 47270
(2017/10/19)

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)

COMPOSITIONS AND METHODS FOR REDUCTION OF KETONES, ALDEHYDES AND IMINIUMS, AND PRODUCTS PRODUCED THEREBY
A method of producing an alcohol, comprises reducing an aldehyde or a ketone with a hydridosilatrane. The reducing is carried out with an activator.
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Paragraph 0076-0077

(2018/01/20)

Sodium Diisopropylamide in N,N-Dimethylethylamine: Reactivity, Selectivity, and Synthetic Utility
The reactivities and chemoselectivities of sodium diisopropylamide (NaDA) in N,N-dimethylethylamine (DMEA) are compared with those of lithium diisopropylamide (LDA) in tetrahydrofuran (THF). Metalations of arenes, epoxides, ketones, hydrazones, dienes, and alkyl and vinyl halides are represented. The positive attributes of NaDA-DMEA include high solubility, stability, resistance to solvent decomposition, and ease of preparation. The high reactivities and chemoselectivities often complement those of LDA-THF.
Ma, Yun,Algera, Russell F.,Collum, David B.
p. 11312 - 11315
(2016/11/29)

Palladium-catalyzed electrophilic C–H fluorination of arenes using oxazoline as a removable directing group
Dimethyloxazoline was rationally designed to act as a removable ortho-directing group (DG) for the palladium-catalyzed C–H electrophilic fluorination of arenes. Using NFSI as the fluorinating agent, and Pd(II), Ag(I) catalytic system, electrophilic C(sp2–H) ortho-fluorination took place on a variety of aryl substrates to afford the corresponding mono- and di-fluorinated products.
Gutierrez, David A.,Lee, Wan-Chen Cindy,Shen, Yuning,Li, Jie Jack
p. 5372 - 5376
(2016/11/11)

Polyurethane nanomicelles: A novel eco-friendly and efficient polymeric ionic solvent for the Cannizzaro reaction
Aqueous polyurethane dispersions (APUDs) are commodity synthetic polymers and have a broad range of well-known applications, nevertheless their possible use as a green catalyst or ionic solvent is yet unknown. Here, we demonstrate how a polyurethane dispersion facilitates the progress of the Cannizzaro reaction under very mild alkaline conditions. We introduce anionic polyurethane nanomicelles as an expeditious green polymer ionic solvent for the Cannizzaro reaction. The reusable and novel eco-friendly polymer solvent, excellent yields of the products, low reaction times and low reaction temperatures are the main advantages of this reaction.
Daemi, Hamed,Barikani, Mehdi,Jahani, Mehdi
supporting information
p. 2121 - 2125
(2016/03/19)

Silatrane as a Practical and Selective Reagent for the Reduction of Aryl Aldehydes to Benzylic Alcohols
Hydrosilanes are cheap, readily available substrates, yet they do not see as extensive use for simple carbonyl reductions as borohydrides. Hydrosilane reducing agents broadly fall into one of two general categories: either a) they are easy to handle and require expensive and/or hazardous additives, or b) they are difficult and/or dangerous to handle. This work details the discovery of mild and functional group compatible conditions utilizing hydrosilatrane for the selective reduction of aryl aldehydes to benzylic alcohols without unwanted formation of ethers or deoxygenated products. This method offers significant advances in silane reductions as silatrane is an air- and moisture-stable yet relatively reactive reducing agent that can be used in benchtop open air reactions.
Skrypai, Vladislav,Hurley, Joseph J. M.,Adler, Marc J.
supporting information
p. 2207 - 2211
(2016/05/09)

K-10 and KSF clays as green and recyclable heterogeneous catalysts for the Cannizzaro reaction using DABCO under MWI and solvent-free conditions
Montmorillonite K-10 and KSF clays as recyclable and heterogeneous catalysts are used to catalyze the Cannizzaro reaction by 1,4-diazabicyclo [2.2.2]octane (DABCO) under microwave irradiation (MWI) and solvent-free conditions in excellent yields within seconds. The solid clays applied in the first cycle are recovered and reused in the subsequent reactions.
Marvi, Omid,Talakoubi, Maryam
p. 359 - 365
(2016/05/09)

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 0061; 0062

(2017/01/31)

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)

Direct Carboxylation of Aryl Tosylates by CO2 Catalyzed by in situ-Generated Ni0
A novel Ni0-catalyzed carboxylation of aryl tosylates with carbon dioxide has been achieved under moderate temperatures and atmospheric pressure. In this procedure, the active Ni0 species is generated in situ by simply mixing the Ni0 precatalyst [NiBr2(bipy)] with an excess of manganese metal. This approach requires neither a glove-box nor the tedious preparation of sophisticated intermediate organometallic derivatives. This mild, convenient, and user-friendly process is successfully applied to the valorization of carbon dioxide and the synthesis of versatile reactants with broad tolerance of substituents.
Rebih, Fatima,Andreini, Manuel,Moncomble, Aurlien,Harrison-Marchand, Anne,Maddaluno, Jacques,Durandetti, Muriel
supporting information
p. 3758 - 3763
(2016/03/08)

Uncatalyzed CO2Li-Mediated SNAr Reaction of Unprotected Benzoic Acids via Silicon Trickery
The alkyl and aryllithium nucleophilic aromatic substitution (SNAr) displacement of a fluoro or methoxy group from unprotected 2-fluoro/methoxybenzoic acids is discussed. It was discovered that a TMS group located at the C6-position ortho to the carboxyl group shields effectively the carboxylate against nucleophilic attack, thus reducing dramatically ketone formation, and reorients nucleophilic substitution to the C2-position. The reactions with fluoro-substituted substrate 7 proceed efficiently; in contrast, the use of methoxy-functionalized benzoic acid 8 only affords moderate yields with s-BuLi and PhLi. This uncatalyzed coupling reaction, which provides a direct access to biaryl compounds, presumably proceeds by an addition-elimination sequence via intermediate formation of a resonance-stabilized pentavalent silalactone-Meisenheimer complex.
Belaud-Rotureau, Mickael,Castanet, Anne-Sophie,Nguyen, Thi Huu,Mortier, Jacques
p. 307 - 313
(2016/03/30)

Conversion of nitroalkanes into carboxylic acids via iodide catalysis in water
We report a new method for the conversion of nitroalkanes into carboxylic acids that achieves this transformation under very mild conditions. Catalytic amounts of iodide in combination with a simple zinc catalyst are needed to give good conversions into the corresponding carboxylic acids.
Marcé, Patricia,Lynch, James,Blacker, A. John,Williams, Jonathan M. J.
p. 1013 - 1016
(2016/01/16)

Synthesis, single crystal structure and efficient catalysis for alcohol oxidation of a novel Ru(II) complex with both a N,N,N-tridentate ligand and a pyridinedicarboxylate
A novel N,N,N-tridentate ligand known as 2-(2-pyridylmethylamino)ethylbenzimidazole (pymaeb) was designed and synthesized. This ligand in combination with disodium pyridine-2,6-dicarboxylate (pydic) reacted with RuCl3 to afford a novel complex Ru[2-(2-pyridymethylimino)ethylbenzimidazole]pyridinedicarboxylate [Ru(pymieb)(pydic)] which was characterized by NMR, IR, HR-MS and single crystal X-ray diffraction. Crystal structure analysis revealed that the complex has a distorted octahedral geometry. The complex showed excellent activity for the oxidation of various alcohols with TBHP as oxidation under mild and solvent-free conditions.
Zhang, Yuecheng,Liu, Liu,Cao, Xiaohui,Zhao, Jiquan
p. 170 - 177
(2016/01/15)

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)

Direct conversion of aromatic aldehydes into benzamides via oxidation with potassium permanganate in liquid ammonia
Oxidation of aromatic aldehydes by KMnO4 in liquid ammonia gives amides directly. The reaction proceeds satisfactorily when the aldehydes are activated by electron-withdrawing substituents on the ring.
Antoniak, Damian,Sakowicz, Arkadiusz,Loska, Rafa?,Makosza, Mieczys?aw
supporting information
p. 84 - 86
(2015/02/05)

Fe3O4 nanoparticles/ethyl acetoacetate system for the efficient catalytic oxidation of aldehydes to carboxylic acids
A new methodology for the oxidation of aldehydes promoted by commercially available Fe3O4 nanoparticles (Fe3O4 NPs) activated by ethyl acetoacetate was developed. The use of ethyl acetoacetate as additive was crucial to achieve high reactivities. All reactions were realized under solvent free conditions, using air or tBuOOH as oxidants. Finally, the separation and reuse of the magnetically recoverable nanoparticles make this methodology very practical, simple and economical.
Villano, Rosaria,Acocella, Maria Rosaria,Scettri, Arrigo
p. 2442 - 2445
(2014/05/06)

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)

Nickel-catalysed carboxylation of organoboronates
A nickel/N-heterocyclic carbene (NHC) catalysed carboxylation of aryl-, heteroaryl- and alkenylboronates, affording the corresponding carboxylic acids, has been developed. This transformation proceeds under one atmosphere of CO 2 with a broad range of substrates and exhibits good functional group compatibility. the Partner Organisations 2014.
Makida, Yusuke,Marelli, Enrico,Slawin, Alexandra M. Z.,Nolan, Steven P.
p. 8010 - 8013
(2014/07/08)

Direct carboxylation of simple arenes with CO2 through a rhodium-catalyzed C-H bond activation
Direct carboxylation of simple arenes under atmospheric pressure of CO2 is achieved through a rhodium-catalyzed C-H bond activation without the assistance of a directing group. Various arenes such as benzene, toluene, xylene, electron-rich or electron-deficient benzene derivatives, and heteroaromatics are directly carboxylated with high TONs. This journal is
Suga, Takuya,Mizuno, Hajime,Takaya, Jun,Iwasawa, Nobuharu
supporting information
p. 14360 - 14363
(2015/02/19)

Direct conversion of aromatic aldehydes into benzamides via oxidation with potassium permanganate in liquid ammonia
Oxidation of aromatic aldehydes by KMnO4 in liquid ammonia gives amides directly. The reaction proceeds satisfactorily when the aldehydes are activated by electron-withdrawing substituents on the ring.
Antoniak, Damian,Sakowicz, Arkadiusz,Loska, Rafa?,Makosza, Mieczys?aw
supporting information

(2015/01/08)

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)

Desilylative carboxylation of aryltrimethylsilanes using CO2 in the presence of catalytic phosphazenium salt
An efficient method for the desilylative carboxylation of aryltrimethylsilanes with CO2 catalyzed by phosphazenium salt has been developed. This protocol can provide various arylcarboxylic acids that are important structural motifs in biologically active chemical compounds.
Yonemoto-Kobayashi, Misato,Inamoto, Kiyofumi,Kondo, Yoshinori
supporting information
p. 477 - 479
(2014/04/17)

Is carbon dioxide able to activate halogen/lithium exchange?
The unexpected effect of carbon dioxide on halogen-lithium exchange (HLE) reactions of selected haloarenes with tBuLi was investigated. In an aliphatic hydrocarbon solvent (pentane), the HLE does not occur at ca. -70 C but, surprisingly, pouring the mixture of reactants onto dry ice and subsequent aqueous acidic hydrolysis gave carboxylic acids resulting from the quench of the first-formed aryllithiums with carbon dioxide. This suggests that CO 2 acts as a promoter of the HLE and, subsequently, serves as an electrophile to trap the aryllithium intermediates that are generated in situ. Theoretical DFT calculations were used to develop a plausible mechanism for the reaction, which indicates that CO2 is a much weaker donor than tetrahydrofuran (THF) so the cleavage of inert tBuLi cubic tetramers into more reactive solvated dimeric species (tBuLi)2(CO2) 4 is disfavored by 42.8 kJ per mol of (tBuLi)4. It is possible that this deaggregation process occurs to some extent when a large excess of CO2 is used. Copyright
Durka, Krzysztof,Lulinski, Sergiusz,Dabrowski, Marek,Serwatowski, Janusz
p. 4562 - 4570
(2014/08/05)

Cooperative N-Heterocyclic Carbene (NHC) and Ruthenium Redox Catalysis: Oxidative Esterification of Aldehydes with Air as the Terminal Oxidant
The paper describes a cooperative NHC (N-heterocyclic carbene) and ruthenium-based redox catalysis for the mild aerobic oxidative esterification of various aromatic and heteroaromatic aldehydes. The ruthenium(II) complex Ru(bpz)3(PF6)2 (bpz=2,2′-bipyrazine) as catalyst is shown to be compatible with free NHCs. The NHC is used in these cascade reactions for the umpolung of the aldehyde to form the corresponding Breslow intermediate which in turn gets oxidized to an acylazolium ion by the ruthenium redox catalyst. Air is used as a terminal oxidant for oxidation (regeneration) of the ruthenium catalyst. In addition, we will show that in the absence of the ruthenium redox catalyst and alcohol, NHC-catalyzed aerobic oxidation of aldehydes delivers the corresponding acids in good to excellent yields. Mechanistic studies and DFT calculations supporting our suggested mechanisms are provided. Copyright
Zhao, Junfeng,Mueck-Lichtenfeld, Christian,Studer, Armido
supporting information
p. 1098 - 1106
(2013/05/21)

Kinetics and mechanism of the oxidation of substituted benzaldehydes with bis(pyridine)silver permanganate
The oxidation of thirty-six ortho-, meta- and para-substituted benzaldehydes by bis(pyridine)silver permanganate (BPSP) resulted in the formation of the corresponding benzoic acids. The reaction is first order with respect to both BPSP and aldehydes. The reaction is catalyzed by hydrogen ions. The rate of reaction increases with an increase in the amount of acetic acid in the solvent. The correlation analyses of the rate of oxidation of thirty-six aldehydes were performed in terms of Charton's LDR and LDRS equations. The rate of oxidation of meta- and para-substituted benzaldehydes showed excellent correlation with Charton's LDR equation. The rates of ortho-compounds showed excellent correlation with LDRS equation. The oxidation para-compounds is more susceptible to the delocalization effect. The oxidation of ortho- and meta-compounds exhibited a greater dependence on the field effect. The polar reaction constants are negative indicating an electron-deficient centre in the rate-determining step. A mechanism involving a nucleophilic attack on the carbonyl group by a permanganate-oxygen and a subsequent hydride transfer has been proposed.
Purohit, Trupti,Banerji, Jayshree,Kotai, Laszlo,Sajo,Banerji,Sharma, Pradeep K.
p. 1045 - 1052
(2013/01/14)

Structure-Reactivity correlation in the oxidation of substituted benzaldehydes by tetraethylammonium chlorochromate
Oxidation of 36 monosubstituted benzaldehydes by tetraethylammonium chlorochromate in dimethyl sulphoxide, leads to the formation of corresponding benzoic acids. The reaction is of first order with respect to chlorochromate and aldehydes. The reaction is promoted by H+; the H+ dependence has the form kobs = a + b[H+]. The oxidation of duteriated benzaldehyde exhibits substantial primary kinetic isotope effect. The reaction was studied in 19 different organic solvents and the effect of solvent was analyzed using Taft's and Swain's multiparametric equations. The rates of the oxidation of para- and meta-substituted benzaldehydes showed excellent correlation in terms of Charton's triparametric LDR equation, whereas the oxidation of ortho-substituted benzaldehydes were correlated well with tetraperametric LDRS equation. The oxidation of para-substituted benzaldehydes is more susceptible to the delocalized effect than is the oxidation of ortho- and meta- substituted compounds, which display a greater dependence on the field effect. The positive value of h suggests the presence of an electron-deficient reaction centre in the rate-determining step. The reaction is subjected to steric acceleration by the orthosubstituents. A suitable mechanism has been proposed.
Gehlot,Prasadrao,Sharma
experimental part
p. 1173 - 1178
(2012/01/05)

Palladium(II)-catalyzed selective monofluorination of benzoic acids using a practical auxiliary: A weak-coordination approach
Finally, a choice! A highly selective palladium(II)-catalyzed ortho-monofluorination reaction has been achieved for the first time through a weak coordination (see scheme; Ar=2,3,5,6-tetrafluoro-4-(trifluoromethyl)phenyl) . Simple modification of this protocol allows for a choice between mono- and difluorination. The mono- and difluorinated benzoic acid derivatives are valuable in the pharmaceutical and agrochemical industries. Copyright
Chan, Kelvin S. L.,Wasa, Masayuki,Wang, Xisheng,Yu, Jin-Quan
supporting information; experimental part
p. 9081 - 9084
(2011/10/17)

Kinetics of proton transfer between ortho substituted benzoic acids and the carbinol base of crystal violet in toluene. Ortho effect on the reactivity of benzoic acids in apolar aprotic solvents
Apolar aprotic solvents are particularly advantageous for investigating the intrinsic ortho effect free from complications of specific solvent effects. A kinetic study for toluene-phase proton transfers between ortho F, Cl, Br, I, OMe, OEt, OPh, OAc, Me, NO2, COMe, COPh, OH, NH2, and H benzoic acids and crystal violet carbinol base has shown the forward rate constant (log k+1) is the most appropriate reactivity parameter in toluene. log k+1 (toluene) as compared to other reported reactivity parameters in benzene, toluene, or chlorobenzene has been found more sensitive to the ortho substituent effect. The regression results of the correlation of log k+1 (toluene) of the acids (except OH and NH2 substituted ones) according to seven ortho effect models are all very significant, and the best result is given by Fujita-Nishiokas model. The overall analysis reveals that a substituents ortho effect pattern is a 58:24:18 ratio of its ordinary electrical, proximity electrical, and steric effects and that the proximity electrical effect is the major component to account for the peculiarity of the substituents ortho effect. The results further favor the transmission of this effect mainly through the molecular cavity. The effect may, however, be outweighed by the steric component for bulky enough substituents, e.g., Me. The enhanced strength exhibited by salicylic acid in toluene has been quantitatively described using Pytela-Lisas δHB i parameter. The abnormally high log k+1 observed for anthranilic acid in toluene has been ascribed to a very extensive homoconjugation in its acid-acid anion complex induced by the acids three hydrogen bond donors.
Sen Gupta, Susanta K.,Mishra, Sangeeta
experimental part
p. 4616 - 4623
(2011/06/26)

Influence of solvent on the ortho substituent effect in the alkaline hydrolysis of phenyl esters of substituted benzoic acids
The second-order rate constants k (dm3mol-1 s -1) for the alkaline hydrolysis of phenyl esters of meta-, para-and ortho-substituted benzoic acids in aqueous 5.3 M NaClO4 and 1.0 M Bu4NBr were measured by UV/Vis spectrophotometry at 25 °C. The variations in the ortho inductive, ortho resonance, as well as meta and para polar effects with solvent parameters were studied using data for the alkaline hydrolysis of phenyl esters of substituted benzoic acids in various media. The dependence of the ortho substituent effect on solvent can be precisely described with the following equation: δlog kortho = log k ortho - log kH = 0.059 + 2.19σ1 +0.304σ°R + 2.79EBs -0.016 δEσ1-0.085δEσ°R, where δE is the solvent electrophilicity, δE = ES-E H2O, characterizing the hydrogen-bond donating power of the solvent. The increase in the meta and para polar substituent effects with decrease in the solvent hydrogen-bond donor capacity (electrophilicity) was approximately to the same extent (-0.068δEσ°m, p) as the resonance term for the ortho substituents. The steric term of ortho substituents was independent of the solvent parameters. The variations in the ortho inductive, ortho resonance, as well as meta and para polar substituent effects with the solvent electrophilicity were to the same extent as in phenyl benzoates containing the substituents in the phenyl part. The substituent effects in the alkaline hydrolysis of ethyl benzoates appeared to vary with the solvent electrophilicity nearly to the same extent as in the alkaline hydrolysis of substituted phenyl esters of benzoic acids. Copyright 2009 John Wiley Sons, Ltd.
Nummert, Vilve,Piirsalu, Mare,Koppel, Ilmar A.
experimental part
p. 497 - 504
(2011/08/08)

Electronic and steric effects: How do they work in ionic liquids? the case of benzoic acid dissociation
(Figure Presented) The need to have a measure of the strength of some substituted benzoic acids in ionic liquid solution led us to use the protonation equilibrium of sodium p-nitrophenolate as a probe reaction, which was studied by means of spectrophotometric titration at 298 K. In order to evaluate the importance of electronic effect of the substituents present on the aromatic ring, both electron-withdrawing and -donor substituents were taken into account. Furthermore, to have a measure of the importance of the steric effect of the substituents both para- and ortho-substituted benzoic acids were analyzed. The probe reaction was studied in two ionic liquids differing for the ability of the cation to give hydrogen bond and π-π interactions, namely [bm 2im][NTf2] and [bmpyrr][NTf2]. Data collected show that benzoic acids are less dissociated in ionic liquid than in water solution. Furthermore, the equilibrium constant values seem to be significantly affected by both the nature of ionic liquid cation and the structure of the acid. In particular, the ortho-steric effect seems to operate differently in water and in the aromatic ionic liquid, determining in this solvent medium a particular behavior for ortho-substituted benzoic acids.
D'Anna, Francesca,Marullo, Salvatore,Vitale, Paola,Noto, Renato
experimental part
p. 4828 - 4834
(2010/10/04)