cas 579-07-7, 1-PHENYL-1,2-PROPANEDIONE | Articles data

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Catalyst-Free and Transition-Metal-Free Approach to 1,2-Diketones via Aerobic Alkyne Oxidation
A catalyst-free and transition-metal-free method for the synthesis of 1,2-diketones from aerobic alkyne oxidation was reported. The oxidation of various internal alkynes, especially more challenging aryl-alkyl acetylenes, proceeded smoothly with inexpensive, easily handled, and commercially available potassium persulfate and an ambient air balloon, achieving the corresponding 1,2-diketones with up to 85% yields. Meanwhile, mechanistic studies indicated a radical process, and the two oxygen atoms in the 1,2-diketons were most likely from persulfate salts and molecular oxygen, respectively, rather than water.
Shen, Duyi,Wang, Hongyan,Zheng, Yanan,Zhu, Xinjing,Gong, Peiwei,Wang, Bin,You, Jinmao,Zhao, Yulei,Chao, Mianran
p. 5354 - 5361
(2021/05/05)

One-pot cascade synthesis of α-diketones from aldehydes and ketones in water by using a bifunctional iron nanocomposite catalyst
A new methodology for the synthesis of α-diketones was reportedviaa one-pot cascade process from aldehydes and ketones catalyzed by a bifunctional iron nanocomposite using H2O2as a green oxidant in water. The one-pot strategy showed excellent catalytic stability, comprehensive suitability of substrates and important practical utility for directly synthesizing biologically active and medicinally valuable N-heterocyclesviaan intermittent process.
Song, Tao,Zhou, Xin,Wang, Xiaoxue,Xiao, Jianliang,Yang, Yong
supporting information
p. 1955 - 1959
(2021/03/26)

Ozonolysis of Alkynes - A Flexible Route to Alpha-Diketones: Synthesis of AI-2
A mild procedure for the low-temperature conversion of alkynes to diketones has been developed and employed in the synthesis of AI-2.
Alterman, Joshua L.,Halverson, Larry J.,Kraus, George A.,Stroud, Marissa Roghair,Vang, Dua X.
supporting information
p. 7424 - 7426
(2020/10/05)

Ancillary ligands switch the activity of Ru–NHC-based oxidation precatalysts
Herein we demonstrate how the inner-sphere coordinating ligands switch the activity of Ru–NHC-based oxidation precatalysts in the oxidative conversion of olefins to carbonyl compounds, with the help of a series of systematically varied imidazolydene-NHC (Im-NHC) and triazolydene-NHC (Tz-NHC)-based ruthenium(II)-complexes. It is shown that the catalytic activity of the para-cymene-containing precatalysts varies in the order of [(Tz-NHC)Ru(para-cymene)Cl]+ > [(Im-NHC)Ru(para-cymene)Cl]+, while the order of activity of the MeCN-containing precatalysts is found to be reversed, i.e., [(Im-NHC)Ru(MeCN)4]2+ > [(Tz-NHC)Ru(MeCN)4]2+. Along with the electronic influence of the NHC ligands, the effect of the lability of the para-cymene and MeCN ligands, and the overall charge of the complexes might be attributed toward such a switching of catalytic activity. This finding led to develop a new precatalyst with improved activity which was further utilized in selective oxidation of a series of styrene substrates containing other oxidation-sensitive functionalities.
Gupta, Suraj K.,Mandal, Tanmoy,Gangber, Tejaswinee,Singh, Vivek,Choudhury, Joyanta
(2019/10/28)

Copper(I)-catalyzed aerobic oxidation of α-diazoesters
A practical Cu-catalyzed oxidation of α-diazoesters to α-ketoesters using molecular oxygen as an oxidant has been developed. Both electron-poor and electron-rich aryl α-diazoesters are suitable substrates and provide the α-ketoesters in good yields. In this oxidative system, α-diazo-β-ketoesters are also compatible as substrates but unexpectedly furnish α-ketoesters via C-C bond cleavage, rather than the vicinal tricarbonyl products.
Xu, Changming,Bai, Lei,Wang, Yongchang
p. 12579 - 12584
(2020/11/09)

Direct Umpolung Morita–Baylis–Hillman like α-Functionalization of Enones via Enolonium Species
Herein we report on the umpolung of Morita–Baylis–Hillman type intermediates and application to the α-functionalization of enone C?H bonds. This reaction gives direct access to α-chloro-enones, 1,2-diketones and α-tosyloxy-enones. The latter are important intermediates for cross-coupling reaction and, to the best of our knowledge, cannot be made in a single step from enones in any other way. The proposed mechanism is supported by spectroscopic studies. The key initial step involves conjugate attack of an amine (DABCO or pyridine), likely assisted by hypervalent iodine acting as a Lewis acid leading to formation of an electrophilic β-ammonium-enolonium species. Nucleophilic attack by acetate, tosylate, or chloride anion is followed by base induced elimination of the ammonium species to give the noted products. Hydrolysis of α-acetoxy-enones lead to formation of 1,2-diketones. The α-tosyl-enones participate in Negishi coupling reactions under standard conditions.
Arava, Shlomy,Kapanaiah, Raja,Pathe, Gulab K.,Santra, Sourav K.,Szpilman, Alex M.
supporting information
p. 15171 - 15175
(2020/07/04)

Palladium-Catalyzed Synthesis of 1,2-Diketones from Aryl Halides and Organoaluminum Reagents Using tert-Butyl Isocyanide as the CO Source
In this work, an interesting and practical procedure for the synthesis of 1,2-diketones from aryl halides and organoaluminum reagents has been developed. Employing tert-butyl isocyanide as the CO source and palladium as the catalyst, the desired 1,2-diketones were isolated in good to excellent yields with good functional group tolerance. Concerning the reaction partners, besides aryl halides, both alkyl- A nd arylaluminum reagents were all suitable substrates here.
Chen, Bo,Wu, Xiao-Feng
supporting information
p. 636 - 641
(2020/01/31)

Bioinspired oxidation of oximes to nitric oxide with dioxygen by a nonheme iron(II) complex
The ability of two iron(II) complexes, [(TpPh2)FeII(benzilate)] (1) and [(TpPh2)(FeII)2(NPP)3] (2) (TpPh2 = hydrotris(3,5-diphenylpyrazol-1-yl)borate, NPP-H = α-isonitrosopropiophenone), of a monoanionic facial N3 ligand in the O2-dependent oxidation of oximes is reported. The mononuclear complex 1 reacts with dioxygen to decarboxylate the iron-coordinated benzilate. The oximate-bridged dinuclear complex (2), which contains a high-spin (TpPh2)FeII unit and a low-spin iron(II)–oximate unit, activates dioxygen at the high-spin iron(II) center. Both the complexes exhibit the oxidative transformation of oximes to the corresponding carbonyl compounds with the incorporation of one oxygen atom from dioxygen. In the oxidation process, the oxime units are converted to nitric oxide (NO) or nitroxyl (HNO). The iron(II)–benzilate complex (1) reacts with oximes to afford HNO, whereas the iron(II)–oximate complex (2) generates NO. The results described here suggest that the oxidative transformation of oximes to NO/HNO follows different pathways depending upon the nature of co-ligand/reductant.
Bhattacharya, Shrabanti,Lakshman, Triloke Ranjan,Sutradhar, Subhankar,Tiwari, Chandan Kumar,Paine, Tapan Kanti
p. 3 - 11
(2019/11/11)

Nature of the Nucleophilic Oxygenation Reagent Is Key to Acid-Free Gold-Catalyzed Conversion of Terminal and Internal Alkynes to 1,2-Dicarbonyls
2,3-Dichloropyridine N-oxide, a novel oxygen transfer reagent, allows the conductance of the gold(I)-catalyzed oxidation of alkynes to 1,2-dicarbonyls in the absence of any acid additives and under mild conditions to furnish the target species, including those derivatized by highly acid-sensitive groups. The developed strategy is effective for a wide range of alkyne substrates such as terminal- and internal alkynes, ynamides, alkynyl ethers/thioethers, and even unsubstituted acetylene (40 examples; yields up to 99%). The oxidation was successfully integrated into the trapping of reactive dicarbonyls by one-pot heterocyclization and into the synthesis of six-membered azaheterocycles. This synthetic acid-free route was also successfully applied for the total synthesis of a natural 1,2-diketone.
Dubovtsev, Alexey Yu.,Shcherbakov, Nikolay V.,Dar'in, Dmitry V.,Kukushkin, Vadim Yu.
p. 745 - 757
(2020/02/04)

A Bifunctional Iron Nanocomposite Catalyst for Efficient Oxidation of Alkenes to Ketones and 1,2-Diketones
We herein report the fabrication of a bifunctional iron nanocomposite catalyst, in which two catalytically active sites of Fe-Nx and Fe phosphate, as oxidation and Lewis acid sites, were simultaneously integrated into a hierarchical N,P-dual doped porous carbon. As a bifunctional catalyst, it exhibited high efficiency for direct oxidative cleavage of alkenes into ketones or their oxidation into 1,2-diketones with a broad substrate scope and high functional group tolerance using TBHP as the oxidant in water under mild reaction conditions. Furthermore, it could be easily recovered for successive recycling without appreciable loss of activity. Mechanistic studies disclose that the direct oxidation of alkenes proceeds via the formation of an epoxide as intermediate followed by either acid-catalyzed Meinwald rearrangement to give ketones with one carbon shorter or nucleophilic ring-opening to generate 1,2-diketones in a cascade manner. This study not only opens up a fancy pathway in the rational design of Fe-N-C catalysts but also offers a simple and efficient method for accessing industrially important ketones and 1,2-diketones from alkenes in a cost-effective and environmentally benign fashion.
Ma, Zhiming,Ren, Peng,Song, Tao,Xiao, Jianliang,Yang, Yong,Yuan, Youzhu
p. 4617 - 4629
(2020/05/19)

B2pin2-mediated copper-catalyzed oxidation of alkynes into 1,2-diketones using molecular oxygen
An intriguing aerobic oxidation of alkynes through copper catalysis is described, in which bis(pinacolato)diboron (B2pin2) played a dominant intermediary role in the formation 1,2-diketones. This novel protocol, which can be performed at room temperature, is versatile for various substituted alkynes, including diarylalkynes and arylalkylalkynes. The mechanism of this reaction was preliminarily investigated by control experiments.
Zhai, Yadong,Su, Zhenni,Jiang, Hao,Rong, Jing,Qiu, Xianfan,Tao, Chuanzhou
supporting information
p. 843 - 846
(2019/02/19)

Electrochemical synthesis of 1,2-diketones from alkynes under transition-metal-catalyst-free conditions
We report an electrochemical protocol for the direct oxidation of internal alkynes in air to provide 1,2-diketones. A variety of functional groups and heterocycle-containing substrates can be tolerated well under mild conditions.
Zhou, Jie,Tao, Xiang-Zhang,Dai, Jian-Jun,Li, Chen-Guang,Xu, Jun,Xu, Hong-Mei,Xu, Hua-Jian
supporting information
p. 9208 - 9211
(2019/08/07)

Regio- and stereoselective multi-enzymatic aminohydroxylation of β-methylstyrene using dioxygen, ammonia and formate
We report an enzymatic route for the formal regio- and stereoselective aminohydroxylation of β-methylstyrene that consumes only dioxygen, ammonia and formate; carbonate is the by-product. The biocascade entails highly selective epoxidation, hydrolysis and hydrogen-borrowing alcohol amination. Thus, β-methylstyrene was converted into 1R,2R and 1S,2R-phenylpropanolamine in 59-63% isolated yields, and up to >99.5 : 0.5 dr and er.
Corrado, Maria L.,Knaus, Tanja,Mutti, Francesco G.
supporting information
p. 6246 - 6251
(2019/12/03)

Synthesis, characterization and catalytic epoxidation properties of a new tellurotungstate(iv)-supported rhenium carbonyl derivative
A monomeric tellurotungstate(iv)-supported rhenium carbonyl derivative: Na2H2[(CH3)4N]6[Te2W20O70{Re(CO)3}2]·20H2O (1) has been successfully isolated and structurally characterized by single crystal X-ray diffraction crystallography, IR and UV-Vis spectroscopy, thermogravimetric analysis, etc. In particular, complex 1 could act as a efficient and reusable heterogeneous catalyst for selective epoxidation of various alkenes including different cycloalkenes, styrene derivatives, internal and long-chain alkenes. For example, cis-cyclooctene undergoes up to 98.2% conversion and >99% selectivity at 75 °C in acetonitrile with 30% H2O2 as an oxidant. Additionally, the electrocatalytic property of 1 for NO2? reduction was also investigated.
Lu, Jingkun,Ma, Xinyi,Wang, Ping,Feng, Junwei,Ma, Pengtao,Niu, Jingyang,Wang, Jingping
p. 628 - 634
(2019/01/08)

Synthesis of a new class of cationic Pd(II) complexes with 1,2,3-triazol-5-ylidene ligand and their catalytic application in the conversion of internal alkynes to 1,2-diketones
A new class of cationic Pd(II) complexes of the type [Pd(Tz)(Cl)(bipy)]+Cl? and [Pd (Tz)(Cl)(phen)]+Cl? (Tz = 1,4-diaryl-3-methyl-1,2,3-triazol-5-ylidene, bipy = 2,2′-bipyridine and phen = 1,10-phenanthroline) with various wing tip groups were synthesized from the corresponding 1,2,3-triazolium iodide via the corresponding chloro bridged dinuclear complexes [(Tz)(Cl)Pd(μ-Cl)2Pd(Cl)(Tz)]. The synthesized cationic complexes were screened for their catalytic activity of hydration of alkynes and found to be excellent towards the selective conversion of internal alkynes to the corresponding 1,2-diketones in good yields. A plausible mechanism was proposed for this conversion.
Shaik, Jeelani Basha,Ramkumar, Venkatachalam,Sankararaman, Sethuraman
supporting information
p. 1 - 8
(2018/02/19)

Displacement of Dinitrogen by Oxygen: A Methodology for the Catalytic Conversion of Diazocarbonyl Compounds to Ketocarbonyl Compounds by 2,6-Dichloropyridine-N-oxide
Dirhodium(II) catalyzed dinitrogen extrusion from diazocarbonyl compounds by 2,6-dichloropyridine-N-oxide forms ketocarbonyl compounds in near-quantitative yields. Reactions occur at room temperature, and the pyridine product does not coordinate with dirhodium(II) to inhibit catalysis. Anhydrous tricarbonyl compounds, as well as dicarbonyl compounds, are conveniently prepared by this methodology, and they have been used in situ for catalytic ene and aldol transformations.
Yu, Yang,Sha, Qiang,Cui, Hui,Chandler, Kory S.,Doyle, Michael P.
supporting information
p. 776 - 779
(2018/02/09)

Magnetic magnetite nanoparticals catalyzed selective oxidation of Α-hydroxy ketones with air and one-pot synthesis of benzilic acid and phenytoin derivatives
A clean and efficient protocol for selective oxidation of α-hydroxy ketones using magnetic magnetite nanoparticals (Fe3O4·MNPs) as catalyst with air as green oxidant has been developed. Application of Fe3O4·MNPs was also proved to be successful in one-pot synthesis of benzilic acid and phenytoin derivatives. The facile one-pot procedure enhanced the production efficiency, shortened the reaction time and minimized the chemical waste. Notably, the catalyst can be reused at least for five times without any appreciable loss of its activity.
Li, Xiaona,Xia, Dandan,Wen, Zhiyong,Gong, Bowen,Sun, Maolin,Wu, Yue,Zhang, Jie,Sun, Jun,Wu, Yang,Bao, Kai,Zhang, Weige
p. 63 - 69
(2018/06/26)

Method for synthesizing novel photoinitiator 1-phenyl-1,2-propanedione
The invention relates to a new process for synthesizing a novel photoinitiator 1-phenyl-1,2-propanedione. The process comprises the steps of subjecting propiophenone, which serves as a starting raw material, to a reaction with ethyl nitrite in the presence of hydrogen chloride so as to obtain 1-phenyl-1,2-propanedion-2-oxime, and further carrying out hydrolysis in the presence of a mixed solution of formaldehyde, hydrochloric acid and ethanol, thereby obtaining 1-phenyl-1,2-propanedione. According to the process, the influence on production of 1-phenyl-1,2-propanedion-2-oxime caused by hydrogen chloride in the reaction and the influence on production of 1-phenyl-1,2-propanedione caused by formaldehyde and ethanol during acidic hydrolysis are surveyed, and optimized conditions for producing 1-phenyl-1,2-propanedione are determined.
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Paragraph 0026; 0028

(2017/07/20)

Insertion of an Isolable Dialkylstannylene into C-Cl Bonds of Acyl Chlorides Giving Acyl(chloro)stannanes
The reactions of isolable dialkylstannylene 1 with 1-adamantanoyl, 2,2-dimethylpropanoyl, benzoyl, and substituted benzoyl chlorides afford the corresponding acyl(chloro)stannanes in good yields. Similar reactions with more reactive acetyl and propanoyl c
Lu, Qiong,Yan, Chenting,Xiao, Xu-Qiong,Li, Zhifang,Wei, Ningka,Lai, Guoqiao,Kira, Mitsuo
p. 3633 - 3637
(2017/10/03)

Halogen-bonded iodonium ion catalysis: A route to α-hydroxy ketones: Via domino oxidations of secondary alcohols and aliphatic C-H bonds with high selectivity and control
A domino synthesis of α-hydroxy ketones has been developed from benzylic secondary alcohols employing catalytic iodonium ions stabilized by DMSO. The reaction proceeds through an unprecedented sequential oxidation of alcohols to ketone and its α-hydroxylation in a controlled manner. The spectroscopic evidence establishes the possibility of formation of a stable halogen-bonded adduct between DMSO and iodonium ions.
Guha, Somraj,Kazi, Imran,Mukherjee, Pranamita,Sekar, Govindasamy
p. 10942 - 10945
(2017/10/13)

Copper-catalyzed TEMPO oxidative cleavage of 1,3-diketones and β-keto esters for the synthesis of 1,2-diketones and α-keto esters
A copper-catalyzed efficient and practical method has been developed for the synthesis of 1,2-diketones and α-keto esters. TEMPO was used as a radical initiator and scavenger, oxidizing the cleavage of α-methylene of 1,3-diketones and β-keto esters to form 1,2-diketones and α-keto esters. This method provided a general way for the formation of 1,2-dicarbonyl compounds.
Zhou, Peng-Jun,Li, Cheng-Kun,Zhou, Shao-Fang,Shoberu, Adedamola,Zou, Jian-Ping
p. 2629 - 2637
(2017/04/03)

Metal-free oxidative nitration of α-carbon of carbonyls leads to one-pot synthesis of thiohydroximic acids from acetophenones
A metal-free nitration of the α-C-H to carbonyl in propiophenones was achieved with I2/NaNO2 in the presence of an oxidant in dimethyl sulfoxide (DMSO) as the medium. Conversely under similar conditions, reaction of acetophenones produced thiohydroximic acids via a radical-based cascade event which involves oxidative nitration of the α-carbon to a carbonyl followed by Michael addition of the thiomethyl group from DMSO and subsequent rearrangement. Besides DMSO, the scope of the reaction encompasses other symmetrical and unsymmetrical dialkylsulfoxides.
Dighe, Shashikant U.,Mukhopadhyay, Sushobhan,Priyanka, Kumari,Batra, Sanjay
p. 4190 - 4193
(2016/09/09)

New push–pull chromophores. Synthesis of 2-[4-Aryl-3-cyano-5-hydroxy-5-methyl-1H-pyrrol-2(5H)-ylidene]malononitriles
2-Aminoprop-1-ene-1,1,3-tricarbonitrile (malononitrile dimer) reacted with 1-arylpropane-1,2-diones in ethanol in the presence of piperidine to give new donor–acceptor chromophores, 2-[4-aryl-3-cyano-5-hydroxy-5-methyl-1H-pyrrole-2(5H)-ylidene]malononitriles.
Fedoseev,Belikov, M. Yu.,Ershov,Bardasov,Tafeenko
p. 1440 - 1443
(2016/11/29)

Highly selective oxidation of unsaturated hydrocarbons to carbonyl compounds by two-phase catalysis
An efficient method for selective oxidation of unsaturated hydrocarbons to carbonyl compounds was established by using oxidant [bis(acetoxy)iodo]benene and catalyst ruthenium trichloride (0.1?mol?%) in a CH2Cl2/H2O two phase system at 30?°C. Both aromatic and aliphatic olefins could be oxidized via?direct carbon[sbnd]carbon bond cleavage to the corresponding aryl or alkyl aldehydes with good selectivity?(up to 100%). Further, diketone could be obtained from alkyne in high yields with this method.
Mi, Chun,Li, Lu,Meng, Xiang-Guang,Yang, Ren-Qiang,Liao, Xiao-Hong
supporting information
p. 6705 - 6710
(2016/09/28)

A kind of organic chemical intermediate 1,2-dione compounds for catalytic synthesis of
The invention relates to a catalytic synthesis method of an organic chemical intermediate 1,2-diketone compound. Asymmetric aryl alkyl acetylene is taken as a raw material, direct catalytic oxidation reaction is achieved in the presence of a multi-component catalyst/assistant system, so as to prepare the 1,2-diketone compound. Effects of types of components of the catalyst and the assistant are researched by a lot of experiments, and a reaction solvent applicable to the system is properly screened. The synthesis process is high in reaction yield, mild in reaction condition and short in reaction time, is an excellent synthesis method of the 1,2-diketone compound, and has broad large-scale industrial application value and market potential.
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Paragraph 0034-0036

(2016/10/10)

A remote coordination booster enhances the catalytic efficiency by accelerating the generation of an active catalyst
A remote RuII(terpy)2 unit incorporated in conjugation with the [NHC-RuII(para-cymene)] catalytic site, acts as a "coordination booster" for enhancing the catalytic efficiency to achieve excellent performance in selective oxidative scission of various carbon-carbon multiple bonds to the corresponding aldehydes, ketones and diketones. Generation of an active catalyst via oxidative loss of para-cymene from the precatalyst was found to be accelerated by the "coordination booster" through the electronic effect.
Gupta, Suraj K.,Choudhury, Joyanta
supporting information
p. 3384 - 3387
(2016/03/01)

Dramatic Effect of Ancillary NHC Ligand in the Highly Selective Catalytic Oxidative Carbon-Carbon Multiple Bond Cleavage
Selective and controlled oxidation of olefins to aldehydes is a commonly used important transformation in chemistry. However, chemists still use the dangerous and inconvenient ozonolysis method or the less selective, low-yielding Lemieux-Johnson protocol. In a program of developing effective catalysts for this important reaction, we disclose here that an ancillary ligand can play a dramatic role in the above catalytic phenomenon, depending on the design of the ligand precursor chosen. Proof-of-principle is demonstrated with the help of two newly designed [LnRuII-NHC] precatalysts (NHC = an imidazolydene-based NHC, Im-NHC, or a triazolydene-based NHC, Trz-NHC; Ln = para-cymene) for catalytic selective oxidation of olefins/alkynes to carbonyl compounds. With the electron-deficient Trz-NHC ligand, [(para-cymene)RuII(Im-Trz)]+ precatalyst was found to be an order of magnitude more efficient than the [(para-cymene)RuII(Im-NHC)]+ precatalyst.
Gupta, Suraj K.,Sahoo, Sandeep K.,Choudhury, Joyanta
supporting information
p. 2462 - 2466
(2016/08/16)

Transition-Metal-Free Deacylative Cleavage of Unstrained C(sp3)-C(sp2) Bonds: Cyanide-Free Access to Aryl and Aliphatic Nitriles from Ketones and Aldehydes
A transition-metal-free deacylative C(sp3)-C(sp2) bond cleavage for the synthetically practical oxidative amination of ketones and aldehydes to nitriles is first described, using cheap and commercially abundant NaNO2 as the oxidant and the nitrogen source. Various nitriles bearing aryl, heteroaryl, alkyl, and alkenyl groups could be smoothly obtained from ketones and aldehydes in high yields, avoiding highly toxic cyanides or transition metals.
Ge, Jing-Jie,Yao, Chuan-Zhi,Wang, Mei-Mei,Zheng, Hong-Xing,Kang, Yan-Biao,Li, Yadong
p. 228 - 231
(2016/02/03)

Iron-catalyzed aerobic oxidative cleavage of the C-C σ-bond using air as the oxidant: Chemoselective synthesis of carbon chain-shortened aldehydes, ketones and 1,2-dicarbonyl compounds
A simple iron-catalyzed aerobic oxidative C-C σ-bond cleavage of ketones has been developed. Readily available and environmentally benign air is used as the oxidant. This reaction avoids the use of noble metal catalysts or specialized oxidants, chemoselectively yielding carbon chain-shortened aldehydes, ketones and 1,2-dicarbonyl compounds without overoxidation.
Xing, Qi,Lv, Hui,Xia, Chungu,Li, Fuwei
supporting information
p. 489 - 492
(2016/01/12)

A selective, efficient and environmentally friendly method for the oxidative cleavage of glycols
A catalytic methodology for the oxidative cleavage of vicinal diols is described as an advantageous alternative in terms of the environmental impact on classical methods involving toxic oxidants. The novel strategy is based on the use of dioxomolybdenum(vi) complexes as catalysts and dimethyl sulfoxide (DMSO) as an oxidant and displays high selectivity and a broad scope for glycol cleavage. In addition, the developed system is also useful for the oxidation of acyloins to diketones.
García, Nuria,Rubio-Presa, Rubén,García-García, Patricia,Fernández-Rodríguez, Manuel A.,Pedrosa, María R.,Arnáiz, Francisco J.,Sanz, Roberto
p. 2335 - 2340
(2016/05/19)

Dendrimer-like core cross-linked micelle stabilized ultra-small gold nanoclusters as a robust catalyst for aerobic oxidation of α-hydroxy ketones in water
As one of the most general and promising stabilizers, dendrimers have been widely used to prepare ultra-small gold nanoclusters. However, the complex synthesis of dendrimers hinders the further application of protected nanoclusters. Here we report a facile strategy to prepare an alternative material via core cross-linking of self-assembled micelles. The resulting dendrimer-like core cross-linked micelles (DCCMs) retain the main characteristics of dendrimers and avoid complex chemical synthesis. As expected, the DCCMs could easily encapsulate gold nanoparticles within their cores. The ultra-small clusters of Au5 were prepared without the participation of external reductants. Importantly, the DCCM stabilized noble gold clusters furnish excellent catalytic activity and perfect reusability for aerobic oxidation of α-hydroxy ketones in water. Only in open air the oxidation could be repeated up to 48 times with negligible turn-over frequency change. The total turnover number (TON) of the reaction reached unexpectedly >48 000, the highest TON for metal catalysed oxidation of hydroxy ketones so far. The further mechanism study hints that the carboxylic group of substrates might be involved in the catalytic process. The simple catalyst preparation, the environmentally benign reaction conditions, and the excellent catalytic performance and durability make the novel DCCM protected gold nanocluster a green catalyst.
Yu, Yangyang,Lin, Chenlu,Li, Bing,Zhao, Pengxiang,Zhang, Shiyong
p. 3647 - 3655
(2016/07/06)

A versatile and one-pot strategy to synthesize ?±-amino ketones from benzylic secondary alcohols using N -bromosuccinimide
A metal-free one-pot strategy has been developed for the first time to synthesize pharmaceutically important ?±-amino ketones from readily available benzylic secondary alcohols and amines using N-bromosuccinimide. This new reaction proceeds via three consecutive steps involving oxidation of alcohols, ?±-bromination of ketones, and nucleophilic substitution of ?±-bromo ketones to give ?±-amino ketones. Importantly, this novel one-pot greener reaction avoids direct usage of toxic and corrosive bromine. This methodology has been employed efficiently to synthesize pharmaceutically important amfepramone and pyrovalerone in a single step.
Guha, Somraj,Rajeshkumar, Venkatachalam,Kotha, Surya Srinivas,Sekar, Govindasamy
p. 406 - 409
(2015/03/04)

Oxidation of phenyl propyne catalyzed by copper(II) complexes of a benzimidazolyl schiff base ligand: Effect of acid/base, oxidant, surfactant and morphology
Copper(II) complexes with a new N-Substituted benzimidazolyl schiff base ligand are used as catalyst for the oxidation of 1-phenyl propyne. The oxidation is carried out under mild conditions using stoichiometric amounts of oxidant and catalytic amounts of Cu(II) complex as catalyst. Effect of acid/base, oxidant, morphology and surfactant has been studied. Two major products of phenyl propyne oxidation are the α-diketonic product and a terminal aldehyde. Diketone is the major product under acidic conditions while aldehyde formation is highest under basic conditions. The maximum conversion is found with the NO3- bound complex. GC-MS is used to find the percentage yields of products. SEM and PXRD of the reused complexes as catalyst suggest that morphology affects the catalytic efficiency.
Kumar, Ravinder,Mathur, Pavan
p. 818 - 823
(2015/02/19)

A Nucleophilic Strategy for Enantioselective Intermolecular α-Amination: Access to Enantioenriched α-Arylamino Ketones
The enantioselective addition of anilines to azoalkenes was accomplished through the use of a chiral phosphoric acid catalyst. The resulting α-arylamino hydrazones were obtained in good yields and excellent enantioselectivities and provide access to enantioenriched α-arylamino ketones. A serendipitous kinetic resolution of racemic α-arylamino hydrazones is also described.
Miles, Dillon H.,Guasch, Joan,Toste, F. Dean
p. 7632 - 7635
(2015/07/02)

A Desulfonylative Approach in Oxidative Gold Catalysis: Regiospecific Access to Donor-Substituted Acyl Gold Carbenes
Donor-substituted acyl gold carbenes are challenging to access selectively by gold-promoted intermolecular oxidation of internal alkynes as the opposite regioisomers frequently predominate. By using alkynyl sulfones or sulfonates as substrates, the oxidative gold catalysis in the presence of substituted pyridine N-oxides offers regiospecific access to acyl/aryl, acyl/alkenyl, and acyl/alkoxy gold carbenes by in situ expulsion of sulfur dioxide. The intermediacies of these reactive species are established by their reactivities, including undergoing further oxidation by the same oxidant, cyclopropanation of styrenes, engaging in a [3+2] cycloaddition with α-methylstyrene, and conversion into dienones. Accept it: A desulfonylative approach was developed to regiospecifically access these underexplored acyl gold carbenes from either alkynyl aryl/alkenyl sulfones or alkynyl sulfonate substrates. The reactivities of these donor- and acceptor-substituted carbenes are examined.
Chen, Hongyi,Zhang, Liming
p. 11775 - 11779
(2015/10/05)

Selectfluor-Mediated Simultaneous Cleavage of C-O and C-C Bonds in α,β-Epoxy Ketones under Transition-Metal-Free Conditions: A Route to 1,2-Diketones
Selectfluor-mediated simultaneous cleavage of C-O and C-C bonds in α,β-epoxy ketones has been successfully achieved under transition-metal-free conditions. The reaction gives 1,2-diketone compounds in moderate to good yields involving a ring-opening/benzoyl rearrangement/C-C bond cleavage sequence under oxidative conditions.
Wang, Heng,Ren, Shaobo,Zhang, Jian,Zhang, Wei,Liu, Yunkui
p. 6856 - 6863
(2015/10/06)

Hypervalent Iodine Mediated C-C Double Bond Activation: A Cascade Access to α-Keto Diacetates from Readily Available Cinnamic Acids
The reaction of cinnamic acids with (diacetoxyiodo)benzene in 1,2-dichloroethane in the presence of sulfuric acid provides an easy and direct access to the α-keto diacetate framework. This hypervalent iodine mediated oxidative reaction involves a tandem sequence of aryl migration, insertion of an oxygen atom, decarboxylation and diacetoxylation. A reaction mechanism is proposed and discussed in light of control experiments.
Liu, Le,Zhang-Negrerie, Daisy,Du, Yunfei,Zhao, Kang
p. 2924 - 2930
(2015/09/28)

Copper(I)-catalyzed oxidation of alkenes using molecular oxygen and hydroxylamines: Synthesis and reactivity of α-oxygenated ketones
The copper(I)-catalyzed oxidation of alkenes with molecular oxygen and N-hydroxyphthalimide (NHPI) or N-hydroxybenzotriazole (HOBt) provided α-oxygenated ketones. The reaction proceeded under a balloon of O2 at room temperature to furnish the dioxygenated products in 50-90% yield. These compounds, particularly the HOBt derivatives, can be further functionalized with phosphorus, nitrogen, and sulfur nucleophiles to give synthetically useful products.
Andia, Alexander A.,Miner, Matthew R.,Woerpel
p. 2704 - 2707
(2015/06/16)

Iodine-mediated oxidative annulation for one-pot synthesis of pyrazines and quinoxalines using a multipathway coupled domino strategy
An efficient iodine-mediated oxidative annulation of aryl acetylenes-arylethenes-aromatic ketones with 1,2-diamines for the synthesis of pyrazines and regioselective synthesis of quinoxalines is presented. A multipathway coupled domino approach has been developed for the one-pot synthesis of 1,4-diazines with high functional group compatibility.
Viswanadham, K. K. Durga Rao,Prathap Reddy, Muktapuram,Sathyanarayana, Pochampalli,Ravi, Owk,Kant, Ruchir,Bathula, Surendar Reddy
supporting information
p. 13517 - 13520
(2015/01/09)

Preparation of polymer incarcerated gold nanocluster catalysts (PI-Au) and their application to aerobic oxidation reactions of boronic acids, alcohols, and silyl enol ethers
Heterogeneous gold nanocluster catalysts immobilized by the method known as polymer incarceration were prepared. Polystyrene-derived polymers with epoxide and alcohol moieties, which could be cross-linked under heating conditions, were employed as supports for their preparation. Cationic gold salts were reduced in a solution of NaBH4 and the polymers. Poor solvents for the polymers were added, and the polymers were precipitated and encapsulated gold nanoclusters with weak but multiple interactions between a gold nanocluster surface and the π electrons of benzene rings. The polymer capsules were heated under neat conditions to afford heterogeneous gold nanocluster catalysts; namely, polymer-incarcerated gold nanoclusters. The catalysts thus prepared could be applied to the aerobic oxidation of phenyl boronic acids, alcohols, and silyl enol ethers. We found that the choice of polymers, good and poor solvents for the polymers, metal loadings, heating conditions for cross-linking, and final activation were all crucial for obtaining high-activity catalysts.
Miyamura, Hiroyuki,Yasukawa, Tomohiro,Kobayashi, Shu
p. 6039 - 6049
(2015/03/30)

A highly efficient catalyst for selective oxidative scission of olefins to aldehydes: Abnormal-NHC-Ru(II) complex in oxidation chemistry
The utility and selectivity of the catalyst [Ru(COD)(L1)Br2] (1) bearing a fused π-conjugated imidazo[1,2-a][1,8]naphthyridine-based abnormal N-heterocyclic carbene ligand L1 is demonstrated toward selective oxidation of C=C bonds to aldehydes and C=C bonds to α-diketones in an EtOAc/CH3CN/H2O solvent mixture at room temperature using a wide range of substrates, including highly functionalized sugar- and amino acid-derived compounds.
Daw, Prosenjit,Petakamsetty, Ramu,Sarbajna, Abir,Laha, Siladitya,Ramapanicker, Ramesh,Bera, Jitendra K.
supporting information
p. 13987 - 13990
(2015/01/08)

Synthesis of α-diketones from alkylaryl- and diarylalkynes using mercuric salts
Both alkylarylalkynes and diarylalkynes 1 are converted into the α-diketones 2 in good yield by the use of mercuric salts, e.g., mercuric nitrate hydrate or mercuric triflate, in the presence of water. Other mercuric salts, e.g., sulfate, chloride, acetate, or trifluoroacetate, do not provide the diketone product. A possible mechanism is proposed.
Jung, Michael E.,Deng, Gang
supporting information
p. 2142 - 2145
(2014/05/06)

Selective oxygenation of alkynes: A direct approach to diketones and vinyl acetate
Arylalkynes can be converted into α-diketones with the use of a copper catalyst, and also be transformed into vinyl acetates under metal-free conditions, both in the presence of PhI(OAc)2 as an oxidant at room temperature. A series of substituted α-diketones were prepared in moderate to good yields. A variety of vinyl halides could be regio- and stereo-selectively synthesized under mild conditions, and I, Br and Cl could be all easily embedded into the alkynes. This journal is
Xia, Xiao-Feng,Gu, Zhen,Liu, Wentao,Wang, Ningning,Wang, Haijun,Xia, Yongmei,Gao, Haiyan,Liu, Xiang
supporting information
p. 9909 - 9913
(2015/01/09)

N-Heterocyclic carbene-catalyzed double acylation of enones with benzils
Thiazolium carbene-catalyzed reaction of aromatic 1,2-diketones with enones in aprotic solvents gave double acylation products in good yields, whereas hydroacylation products formed by Stetter reaction were not detected at all. These results suggested the generation of aroyloxyenamine species from the 1,2-diketones instead of hydroxyenamines (Breslow intermediates). This journal is
Takaki, Ken,Ohno, Akira,Hino, Makoto,Shitaoka, Takashi,Komeyama, Kimihiro,Yoshida, Hiroto
supporting information
p. 12285 - 12288
(2014/12/11)

N,O-ligated Pd(ii) complexes for catalytic alcohol oxidation
N,O-ligated Pd(ii) complexes show considerable promise for the oxidation of challenging secondary aliphatic alcohols. The crystal structures of the highly active complexes containing the 8-hydroxyquinoline-2-carboxylic acid (HCA) and 8-hydroxyquinoline-2-sulfonic acid (HSA) ligands have been obtained. The (HSA)Pd(OAc)2 system can effectively oxidise a range of secondary alcohols, including unactivated alcohols, within 4-6 h using loadings of 0.5 mol%, while lower loadings (0.2 mol%) can be employed with extended reaction times. The influence of reaction conditions on catalyst degradation was also examined in these studies.
Dornan, Laura M.,Clendenning, Grainne M. A.,Pitak, Mateusz B.,Coles, Simon J.,Muldoon, Mark J.
p. 2526 - 2534
(2014/07/22)

Enantioselective synthesis of 3,4-disubstituted cis- and trans-1,2,5-thiadiazolidine-1,1-dioxides as precursors for chiral 1,2-diamines
Both, cis- and trans-3,4-disubstituted thiadiazolidines 5 and 6 can enantioselectively be obtained from thiadiazoles 2 which, in turn, are efficiently prepared from the respective 1,2-diketone by an improved protocol. An asymmetric ruthenium-catalyzed transfer hydrogenation followed by a diastereoselective hydride addition furnishes exclusively the cis-isomers 5 which, under acidic conditions, undergo a novel isomerization into the trans-isomers 6. These cyclic sulfamides can be transformed into 1,2-diamines as well as 2,3-diamino acids.
Schüttler, Christian,Li-B?hmer, Zhen,Harms, Klaus,Von Zezschwitz, Paultheo
supporting information
p. 800 - 803
(2013/04/24)

A combination of copper(0) powder and selectfluor enables generation of cationic copper species for mild 1,2-dicarbonylation of alkynes
A combination of copper powder and Selectfluor permits the generation of cationic copper species that efficiently catalyze 1,2-dicarbonylation of alkynes under mild conditions with water and dioxygen as inexpensive and environmentally benign sources of oxygen. Georg Thieme Verlag Stuttgart New York.
Zhang, Wenxia,Zhang, Jian,Liu, Yunkui,Xu, Zhenyuan
supporting information
p. 2709 - 2714
(2014/01/06)

I2-catalyzed direct α-hydroxylation of β-dicarbonyl compounds with atmospheric oxygen under photoirradiation
An I2-catalyzed hydroxylation of β-dicarbonyl moieties using air as the oxidant under photoirradiation has been developed for the easy preparation of α-hydroxy-β-dicarbonyl compounds. The transformation was completed with only 1 mol % of I2. With α-unsubstituted malonates, the hydroxylated dimerization product was afforded as the predominant product along with a minor product, α,α-dihydroxyl malonate.
Miao, Chun-Bao,Wang, Yan-Hong,Xing, Meng-Lei,Lu, Xin-Wei,Sun, Xiao-Qiang,Yang, Hai-Tao
p. 11584 - 11589
(2013/12/04)

Oxone-mediated oxidative cleavage of β-keto esters and 1,3-diketones to α-keto esters and 1,2-diketones in aqueous medium
A versatile and highly efficient method for the direct synthesis of α-keto esters and 1,2-diketones has been developed. This approach utilizes the oxidative cleavage of a variety of β-keto esters and 1,3-diketones mediated by an Oxone/aluminum trichloride system. The simple one-step oxidation reaction proceeded selectively in aqueous media to afford products in high yields, short reaction times, and environmentally benign conditions.
Stergiou, Anastasios,Bariotaki, Anna,Kalaitzakis, Dimitris,Smonou, Ioulia
p. 7268 - 7273
(2013/08/15)

2,6-Dicarboxypyridinium fluorochromate-promoted oxidation of alkyl-arenes into carbonyl compounds under nonaqueous and aprotic conditions
Benzylic C-H oxidation of a wide variety of alkyl- and cycloalkyl arenes employing 2,6-dicarboxypyridinium fluorochromate under mild reaction conditions is described. The corresponding carbonyl compounds are obtained in good to excellent yields. Taylor & Francis Group, LLC.
Sarrafi, Yaghoub,Tajbakhsh, Mahmood,Hosseinzadeh, Rahman,Sadatshahabi, Marzieh,Alimohammadi, Kamal
experimental part
p. 678 - 685
(2011/12/21)