- Hydroxylation of benzophenone with ammonium phosphomolybdate in the solid state via UV photoactivation
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UV photoactivation of a mixture of benzophenone and ammonium phosphomolybdate (APM) in the solid state splits adsorbed moisture, resulting in selectively hydroxylated benzophenone and leaving an electron trapped in green (reduced) solid APM. The Royal Soc
- Basu, Mrinmoyee,Sarkar, Suresh,Pande, Surojit,Jana, Subhra,Kumar Sinha, Arun,Sarkar, Sougata,Pradhan, Mukul,Pal, Anjali,Pal, Tarasankar
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- Selective Preparation of Xanthones from 2-Bromofluorobenzenes and Salicylaldehydes via Palladium-Catalyzed Acylation-SNAr Approach
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A regioselective pathway for the preparation of xanthones from 2-bromofluorobenzenes and salicylaldehydes has been developed. The reaction proceeded through palladium-catalyzed acylation-SNAr sequence. Good to moderate yields of the desired xanthones were prepared in one step. Based on the results of control experiments, a possible reaction mechanism has been proposed.
- Shen, Chaoren,Wu, Xiao-Feng
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- Palladium-catalyzed coupling reaction of salicylaldehydes with aryl iodides via cleavage of the aldehyde C-H bond
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It has been found that the cross-coupling reaction of salicylaldehydes with aryl iodides smoothly proceeds by using a catalyst system of PdCl2/LiCl in the presence of Na2CO3 as base to give the corresponding 2-aroylphenols in good yields, which appears to involve cleavage of the aldehyde C-H bond.
- Satoh, Tetsuya,Itaya, Tomoaki,Miura, Masahiro,Nomura, Masakatsu
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- First direct access to 2-hydroxybenzophenones via nickel-catalyzed cross-coupling of 2-hydroxybenzaldehydes with aryl iodides
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An efficient, inexpensive and reusable NiCl2·6H2O/n-Bu4NBr catalytic system is described for the direct C-H arylation of 2-hydroxybenzaldehydes with aryl iodides for the first time.
- Nowrouzi,Zarei,Roozbin
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p. 102448 - 102453
(2015)
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- Rh(III)-catalyzed aldehyde C-H bond functionalization of salicylaldehydes with arylboronic acids
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A Rh(III)-catalyzed aldehyde C-H bond functionalization of salicylaldehydes with arylboronic acids has been developed, with features of mild reaction condition and high efficiency. Furthermore, the functionalized 2-hydroxybenzophenone could be subject to divergent synthesis of heterocycles.
- Wang, Dahai,Cui, Sunliang
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- PdCl2/DABCO-catalyzed direct arylation of 2-hydroxybenzaldehydes in H2O
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In this paper the successful application of DABCO both as base and as ligand for efficient coupling reactions of aryl iodides and bromides with 2-hydroxybenzaldehydes in the presence of catalytic amounts of PdCl2 in water as solvent was introduced.
- Nowrouzi, Najmeh,Tarokh, Dariush
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- Intramolecular photocyclization of 2-acylphenyl methacrylates: A convenient access to 4,5-dihydro-1,4-epoxy-2-benzoxepin-3(1H)-ones =benzo[c]-6,8- dioxabicyclo [3.2.1]octan-7-ones
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The photochemical reactions of 2-acylphenyl methacrylates (=2-acylphenyl 2-methylprop-2-enoates) 1 were investigated. Irradiation of 2-acylphenyl methacrylates 1a-d in MeCN gave the tricyclic lactones 2a-d in good yields, together with a small amount of O-C=O bond cleavage product, the 2-acylphenols 3a-d (Scheme 2, Table). The formation of the tricyclic lactones 2 probably follows a mechanism involving a 1,7-diradical through ζ-H abstraction (1,8-H transfer) by the excited carbonyl O-atom (Scheme 3). Irradiation of 2-acylphenyl tiglate (=2-acylphenyl (2E)-2-methylbut-2-enoate) 1e and 2-acylphenyl methacrylates 1g-i, substituted by a MeO group (δ-H) at the 3,5-positions of the phenylgroup, also gave the tricyclic lactones 2e and 2g-i, but in low yields. On the other hand, no H-abstraction products were observed on irridation of 2-(ethoxycarbonyl)phenyl methacrylate 1f, of 2-acylphenyl methacrylate 1j which is substituted by a Me group (γ-H) at the 3,5-positions of the phenyl group, and of 1k with an OH group at the 3-position of the phenyl group.
- Nishio, Takehiko,Sakurai, Nobuharu,Iba, Kaoru,Hamano, Yo-Ichi,Sakamoto, Masami
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- AN INTRAMOLECULAR OXENOID OXIDATION
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Photooxidation of diphenyldiazomethane and 9-diazofluorene leads to the intramolecular oxenoid oxidation products, o-hydroxybenzophenone and 1-hydroxyfluorenone, respectively.
- Kumar, Shailendra,Murray, Robert W.
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- Palladium-catalyzed direct C-H arylation of 2-hydroxybenzaldehydes with organic halides in neat water
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The palladium-catalyzed cross-coupling of 2-hydroxybenzaldehydes with organic halides proceeds in the presence of n-Bu4NBr in H2O producing the corresponding 2-hydroxybenzophenones in high yields.
- Nowrouzi, Najmeh,Motevalli, Somayeh,Tarokh, Dariush
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- Selective Oxidation of Alkylarenes to the Aromatic Ketones or Benzaldehydes with Water
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Here a palladium-catalyzed oxidation method for converting alkylarenes into the aromatic ketones or benzaldehydes with water as the only oxygen donor is reported. This C-H bond oxidation functionalization does not require other oxidants and hydrogen accep
- Du, Jihong,Duan, Baogen,Liu, Kun,Liu, Renhua,Yu, Feifei,Yuan, Yongkun,Zhang, Chenyang,Zhang, Jin
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supporting information
(2022/02/09)
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- Water-Tolerant ortho-Acylation of Phenols
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A metal-free, water-tolerant, and one-pot process for ortho-acylation of phenols promoted by the iodine source/hydrogen peroxide system has been developed. This transformation undergoes ether formation, iodocyclization, C-C bond cleavage, and oxidative hydrolysis in a one-step manner, which is supported by control experiments.
- Dong, Shuang-Feng,Gao, Zhi-Yuan,He, Yu,Liu, Xu,Loh, Teck-Peng,Tian, Jie-Sheng,Wu, Peng
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supporting information
p. 6594 - 6598
(2021/09/02)
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- Aerobic Copper-Catalyzed Salicylaldehydic Cformyl?H Arylations with Arylboronic Acids
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We report a challenging copper-catalyzed Cformyl?H arylation of salicylaldehydes with arylboronic acids that involves unique salicylaldehydic copper species that differ from reported salicylaldehydic rhodacycles and palladacycles. This protocol has high chemoselectivity for the Cformyl?H bond compared to the phenolic O?H bond involving copper catalysis under high reaction temperatures. This approach is compatible with a wide range of salicylaldehyde and arylboronic acid substrates, including estrone and carbazole derivatives, which leads to the corresponding arylation products. Mechanistic studies show that the 2-hydroxy group of the salicylaldehyde substrate triggers the formation of salicylaldehydic copper complexes through a CuI/CuII/CuIII catalytic cycle.
- Xiao, Lin,Lang, Tao-Tao,Jiang, Ying,Zang, Zhong-Lin,Zhou, Cheng-He,Cai, Gui-Xin
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supporting information
p. 3278 - 3283
(2021/02/01)
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- Electrophotocatalytic C?H Heterofunctionalization of Arenes
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The electrophotocatalytic heterofunctionalization of arenes is described. Using 2,3-dichloro-5,6-dicyanoquinone (DDQ) under a mild electrochemical potential with visible-light irradiation, arenes undergo oxidant-free hydroxylation, alkoxylation, and amination with high chemoselectivity. In addition to batch reactions, an electrophotocatalytic recirculating flow process is demonstrated, enabling the conversion of benzene to phenol on a gram scale.
- Huang, He,Lambert, Tristan H.
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supporting information
p. 11163 - 11167
(2021/04/19)
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- Substituent and Surfactant Effects on the Photochemical Reaction of Some Aryl Benzoates in Micellar Green Environment?
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In this study, we carried out preparative and mechanistic studies on the photochemical reaction of a series of p-substituted phenyl benzoates in confined and sustainable micellar environment. The aim of this work is mainly focused to show whether the nature of the surfactant (ionic or nonionic) leads to noticeable selectivity in the photoproduct formation and whether the electronic effects of the substituents affect the chemical yields and the rate of formation of the 5-substituted-2-hydroxybenzophenone derivatives. Application of the Hammett linear free energy relationship (LFER) on the rate of formation of benzophenone derivatives, on the lower energy band of the UV-visible absorption spectra of the aryl benzoates and 5-substituted-2-hydroxybenzophenone derivatives allows a satisfactory quantification of the substituent effects. Furthermore, UV-visible and 2D-NMR (NOESY) spectroscopies have been employed to measure the binding constant Kb and the location of the aryl benzoates within the hydrophobic core of the micelle. Finally, TD-DFT calculations have been carried out to estimate the energies of the absorption bands of p-substituted phenyl benzoates and 5-substituted-2-hydroxybenzophenone derivatives providing good linear correlation with those values measured experimentally.
- Siano, Gastón,Crespi, Stefano,Bonesi, Sergio M.
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p. 1298 - 1309
(2021/05/07)
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- C?H Oxygenation Reactions Enabled by Dual Catalysis with Electrogenerated Hypervalent Iodine Species and Ruthenium Complexes
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The catalytic generation of hypervalent iodine(III) reagents by anodic electrooxidation was orchestrated towards an unprecedented electrocatalytic C?H oxygenation of weakly coordinating aromatic amides and ketones. Thus, catalytic quantities of iodoarenes in concert with catalytic amounts of ruthenium(II) complexes set the stage for versatile C?H activations with ample scope and high functional group tolerance. Detailed mechanistic studies by experiment and computation substantiate the role of the iodoarene as the electrochemically relevant species towards C?H oxygenations with electricity as a sustainable oxidant and molecular hydrogen as the sole by-product. para-Selective C?H oxygenations likewise proved viable in the absence of directing groups.
- Massignan, Leonardo,Tan, Xuefeng,Meyer, Tjark H.,Kuniyil, Rositha,Messinis, Antonis M.,Ackermann, Lutz
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supporting information
p. 3184 - 3189
(2020/01/24)
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- Eco-friendly organocatalyst- And reagent-controlled selective construction of diverse and multifunctionalized 2-hydroxybenzophenone frameworks for potent UV-A/B filters by cascade benzannulation
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The organocatalyst- and reagent-controlled highly selective synthesis of diversely functionalized novel 2-hydroxybenzophenone frameworks, such as 2-hydroxy-3′-formylbenzophenones, 7-(2′-hydroxybenzoyl)-2-naphthaldehydes, and 2-hydroxybenzophenones, under green conditions, for the development of potent UV-A/B filters is described. The organocatalyzed benzannulation reactions proceed individually via [3 + 3] cycloaddition for the synthesis of 2-hydroxy-3′-formylbenzophenones and [4 + 2] cycloaddition for 2-hydroxybenzophenones. With this methodology, an unprecedented double benzannulation allows one-pot construction of diverse 7-(2′-hydroxybenzoyl)-2-naphthaldehydes via [3 + 3 + 4] cycloaddition. This protocol features a broad substrate scope, high functional-group tolerance, and operational simplicity in an environmentally benign green solvent. The synthesized compounds are successfully utilized for further transformations and well characterized as potent UV-A/B filters.
- Akhtar, Muhammad Saeed,Inductivo Tamargo, Ramuel John,Kim, Sung Hong,Lee, Yong Rok,Thombal, Raju S.,Yang, Won-Guen
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supporting information
p. 4523 - 4531
(2020/08/10)
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- Nickel-Catalyzed Decarbonyloxidation of 3-Aryl Benzofuran-2(3H)-ones to 2-Hydroxybenzophenones
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We have developed a protocol to facilitate the nickel-catalyzed decarbonyloxidation of 3-aryl benzofuran-2(3H)-ones to 2-hydroxybenzophenones under mild conditions, which is an efficient approach for the decarbonyloxidation of lactones in organic synthesis. A diverse range of substrates can undergo C(O)-O/C(O)-C bond cleavage to generate the target products in good yields. These 2-hydroxybenzophenones can be converted into a variety of compounds via reactions such as esterification, cyclization, and reduction.
- Tong, Zhou,Tang, Zhi,Au, Chak-Tong,Qiu, Renhua
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p. 8533 - 8543
(2020/07/16)
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- Binuclear Palladium Complex Immobilized on Mesoporous SBA-16: Efficient Heterogeneous Catalyst for the Carbonylative Suzuki Coupling Reaction of Aryl Iodides and Arylboronic Acids Using Cr(CO)6 as Carbonyl Source
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Abstract: In this study, a binuclear palladium complex immobilized on the organo-functionalized SBA-16 was prepared and structurally characterized by routine techniques. Characterizations indicated that the mesostructure of SBA-16 was maintained after the immobilization of palladium complex. Then, the prepared nanomaterial was applied as a heterogeneous catalyst in the carbonylative Suzuki coupling reaction of aryl iodides with arylboronic acids using Cr(CO)6 as carbonyl source. The catalyst was efficiently promoted the coupling reactions of various aryl iodides and arylboronic acids to give the corresponding diaryl ketones in excellent yields. Moreover, the catalyst was readily recovered by filtration and could be reused for seven cycles without losing its structural integrity and catalytic activity. Graphic Abstract: [Figure not available: see fulltext.].
- Niakan, Mahsa,Asadi, Zahra,Emami, Mohammad
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p. 404 - 418
(2020/01/03)
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- Cu/Ag mediated peroxide-free synthesis of benzoylated naphthol derivatives
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A peroxide-free methodology was developed for the synthesis of benzoylated naphthol/phenol derivatives through oxidative deamination reaction performed under aerobic reaction conditions. A synergistic combination of Cu(OTf)2 and Ag2O was used to convert the aminonaphthols and aminophenols to the corresponding benzoylated derivatives. The definite role of atmospheric oxygen to assist the reaction was proved by performing the reaction in the argon atmosphere.
- Prasanna Kumari, Subramaniyan,Suresh, Pavithira,Muthukumar, Vijayashree,Selva Ganesan, Subramaniapillai
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- Efficient visible-light photocatalytic aerobic oxidation of cyclic sulfamides to imines
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A highly efficient photocatalytic aerobic oxidation of cyclic sulfamides to synthesize cyclic N-sulfonyl imines with Ir(ppy)2(dtbpy)PF6 as photocatalyst is reported. These environmentally friendly transformations exihibit good to excellent isolated yields and good generality with respect to both five-membered and six-membered cyclic sulfamides.
- Ming, Zong-Yao,Li, Kang-Rui,Meng, Fan-Jie,Shi, Lei,Jiang, Wen-Feng
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supporting information
(2020/06/17)
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- Directed Hydroxylation of sp2 and sp3 C-H Bonds Using Stoichiometric Amounts of Cu and H2O2
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The use of copper for C-H bond functionalization, compared to other metals, is relatively unexplored. Herein, we report a synthetic protocol for the regioselective hydroxylation of sp2 and sp3 C-H bonds using a directing group, stoichiometric amounts of Cu and H2O2. A wide array of aromatic ketones and aldehydes are oxidized in the carbonyl γ-position with remarkable yields. We also expanded this methodology to hydroxylate the β-position of alkylic ketones. Spectroscopic characterization, kinetics, and density functional theory calculations point toward the involvement of a mononuclear LCuII(OOH) species, which oxidizes the aromatic sp2 C-H bonds via a concerted heterolytic O-O bond cleavage with concomitant electrophilic attack on the arene system.
- Trammell, Rachel,D'Amore, Lorenzo,Cordova, Alexandra,Polunin, Pavel,Xie, Nan,Siegler, Maxime A.,Belanzoni, Paola,Swart, Marcel,Garcia-Bosch, Isaac
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p. 7584 - 7592
(2019/06/11)
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- Deoxygenative Arylation of Carboxylic Acids by Aryl Migration
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An unprecedented deoxygenative arylation of aromatic carboxylic acids has been achieved, allowing the construction of an enhanced library of unsymmetrical diaryl ketones. The synergistic photoredox catalysis and phosphoranyl radical chemistry allows for precise cleavage of a stronger C?O bond and formation of a weaker C?C bond by 1,5-aryl migration under mild reaction conditions. This new protocol is independent of substrate redox-potential, electronic, and substituent effects. It affords a general and promising access to 60 examples of synthetically versatile o-amino and o-hydroxy diaryl ketones under redox-neutral conditions. Furthermore, it also brings one concise route to the total synthesis of quinolone alkaloid, (±)-yaequinolone A2, and a viridicatin derivative in satisfying yields.
- Ruzi, Rehanguli,Ma, Junyang,Yuan, Xiang-Ai,Wang, Wenliang,Wang, Shanshan,Zhang, Muliang,Dai, Jie,Xie, Jin,Zhu, Chengjian
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p. 12724 - 12729
(2019/11/05)
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- RhIII-Catalyzed Decarboxylative o-Acylation of Arenes Bearing an Oxidizing Directing Group
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Here in we report, rhodium(III)-catalyzed decarboxylative acylation of arenes using α-oxocarboxylic acids as acyl surrogate. In this strategy, O–NHAc group act as an autocleavable oxidizing directing group (ODGauto), thus giving rise to ortho-acylated phenols in moderate to good yields. Mechanistic studies provided strong support for a kinetically relevant C–H bond activation. According to the best of our knowledge, this is the first report of Rhodium catalyzed decarboxylative acylation.
- Bera, Suvankar,Chandrasekhar,Chatterjee, Satadru,Killi, Sunil Kumar,Sarkar, Debabrata,Banerji, Biswadip
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p. 3877 - 3881
(2019/06/28)
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- Selectivity in the photo-fries rearrangement of some aryl benzoates in green and sustainable media. Preparative and mechanistic studies
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Irradiation of a series of p-substituted aryl benzoates under N2 atmosphere in homogeneous and micellar media was investigated by means of steady-state condition and of time-resolved spectroscopy. A notable selectivity in favor of the 2-hydroxybenzophenone derivatives was observed in micellar media. The benzophenone derivatives were the main photoproduct. On the other hand, in homogeneous media (cyclohexane, acetonitrile, and methanol) the observed product distribution was entirely different, viz. substituted 2-hydroxybenzophenones, p-substituted phenols, benzyl and benzoic acid were found. The binding constants in the surfactant were also measured and NOESY experiments showed that the aryl benzoates were located in the hydrophobic core of the micelle. Laser flash photolysis experiments led to the characterization of both p-substituted phenoxy radical and substituted 2-benzoylcyclohexadienone transients in homogeneous and micellar environment.
- Siano, Gastón,Bonesi, Sergio M.,Crespi, Stefano,Mella, Mariella
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p. 4338 - 4352
(2019/05/01)
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- Efficient catalytic synthesis method of 2-hydroxybenzophenone compound
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The invention discloses a 2-hydroxybenzophenone compound and a green catalytic synthesis method thereof. According to the method, under the conditions of using coumaranone and coumaranone derivativesas raw materials, using nickel chloride as a catalyst, using methylbenzene as a solvent, using di-tert-butyl peroxide as an oxidizing agent, and using sodium carbonate as alkali, the 2-hydroxybenzophenone compound is obtained at high yield. The method has the advantages that the cost is low; the yield is high; the operation is simple and convenient; no pollution is caused and the like. The potential industrial application prospects are realized. The method provides a cheap and green path for the preparation of the 2-hydroxybenzophenone compound.
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Paragraph 0019; 0020
(2019/04/11)
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- Photoinduced Hydroxylation of Organic Halides under Mild Conditions
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Presented in this paper is photoinduced hydroxylation of organic halides, providing a mild access to a range of functionalized phenols and aliphatic alcohols. These reactions generally proceed under mild reaction conditions with no need for a photocatalyst or a strong base and show a wide substrate scope as well as excellent functional group tolerance. This work highlights the unique role of NaI that allows a challenging transformation to proceed under mild reaction conditions.
- Cai, Yue-Ming,Xu, Yu-Ting,Zhang, Xin,Gao, Wen-Xia,Huang, Xiao-Bo,Zhou, Yun-Bing,Liu, Miao-Chang,Wu, Hua-Yue
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supporting information
p. 8479 - 8484
(2019/10/16)
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- Synergistic Photo-Copper-Catalyzed Hydroxylation of (Hetero)aryl Halides with Molecular Oxygen
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Photoredox-mediated copper-catalyzed hydroxylation of (hetero)aryl halides (including chlorides, bromides, and iodides) with O2 at room temperature has been developed. Preliminary mechanistic studies indicate no arylcopper intermediate and that aryl radicals are involved in this procedure. 18O-labeling experiments confirm the hydroxyl oxygen atom originated from molecular oxygen.
- Zhang, Xin,Wu, Ge,Gao, Wenxia,Ding, Jinchang,Huang, Xiaobo,Liu, Miaochang,Wu, Huayue
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supporting information
p. 708 - 711
(2018/02/09)
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- Phenol compound and preparation method
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The invention relates to a phenol compound and a preparation method. In an organic solvent, aryl halide and oxygen or air are used as reaction raw materials, and under the combined facilitation effectof a copper catalyst, alkali and an additive, the aryl halide and the oxygen react in illumination of light to obtain the phenol compound. The copper catalyst and the alkali have key effects in a reaction process. The preparation method of the phenol compound has the advantages of wide substrate range, operation at room temperature, simple aftertreatment, high yield and purity of products and thelike. A new synthetic route and method are opened for the phenol compound, and thus, the phenol compound has good application potential and research value.
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Paragraph 0136-0139
(2018/04/27)
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- Modulation of reactivity of singlet radical pair in continuous flow: Photo-Fries rearrangement
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Photo-Fries rearrangement of phenyl benzoate is studied using continuous flow for modulating the reactivity of singlet radical pair by changing the viscosity of the solvent. The effect of flow and proximity of the reactants with the light source on the reactivity of radical pair, formed from singlet excited state was investigated in details. In non-viscous solvent, the results from flow synthesis were comparable to batch reactor. In viscous solvents, selectivity of ortho- and para-isomers (o-/p- isomer) of the product could be controlled by changing viscosity as well as the flow rate. Using flow synthesis, ortho- and para-isomer ratio was obtained as high as 8.45 which are twice as compared to batch experiment with in fraction of residence time.
- Karjule, Neeta,Sharma, Mrityunjay K.,Nithyanandhan, Jayaraj,Kulkarni, Amol A.
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p. 316 - 321
(2018/06/26)
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- Rhodium-Catalyzed Directing-Group-Assisted Aldehydic C–H Arylations with Aryl Halides
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A rhodium-catalyzed general protocol for the directing-group-assisted arylation of aromatic aldehydic C–H bonds was developed. This method involves either hydroxy- or amino-group-directed aldehyde C–H arylation with various aryl halides. A broad synthetic scope for the preparation of 2-hydroxybenzophenones was established with electronically variant salicylaldehydes and aryl halides with chemo- and regioselective possibilities. The developed protocol was also applied in the synthesis of medicinally important 3-salicyloylpyridines in high yields.
- Rao, Maddali L. N.,Ramakrishna, Boddu S.
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p. 5080 - 5093
(2017/09/20)
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- Photocatalytic benzene and benzene derivative direct hydroxylation or amination method
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The invention discloses a photocatalytic benzene and benzene derivative direct hydroxylation or amination method. The method is characterized by comprising the following steps: (1) adding a photo-sensitizer and a cobalt catalyst into a solvent to obtain a solution (A); (2) adding benzene (or benzene derivatives), water, ammonia gas, and amide derivatives (or sulfonamide derivatives) into the solution (A) to obtain a solution (B); and (3) in a N2 (or Ar) environment, radiating the solution (B) by a medium pressure mercury lamp, a high pressure mercury lamp, a xenon lamp, or an LED lamp to obtain phenols or amines and H2. For the first time, a photo-sensitizer and a cobalt catalyst are combined and applied to photocatalytic hydroxylation and amination of benzene. The conditions of the method are mild, light is taken as the driving energy, no oxidant is added, the only byproduct is H2, and the whole process is green, concise, and efficient. High selective benzene one-step hydroxylation to generate phenol or high selective phenol/benzene one-step amination to generate aniline is realized, and the method can be applied to the production of phenol and aniline.
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Paragraph 0120-0121
(2017/11/29)
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- A new synthetic route to benzophenone derivatives
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The rearrangement reaction of 1-alkyl-2-(benzoylmethyl)pyridinium iodides 3a-d, 6 in the presence of various nucleophiles leads to 2-alkylaminobenzophenone derivatives 4a-c. Best results were achieved with alkylammonium sulfites as recyclization reagents.
- Abu-Melha, Sraa
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p. 313 - 316
(2017/08/15)
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- Acid-Functionalised Magnetic Ionic Liquid [AcMIm]FeCl4 as Catalyst for Oxidative Hydroxylation of Arylboronic Acids and Regioselective Friedel–Crafts Acylation
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An acid-functionalised, magnetic, room-temperature ionic liquid, 1-acyl-3-methylimidazolium tetrachloroferrate ([AcMIm]FeCl4), was synthesised and its optical, magnetic, and thermal properties were investigated. The magnetic moment (0.05402 emu in 2 T magnetic fields) showed strong paramagnetic behaviour, and thermogravimetric analysis indicated very good thermal stability with a decomposition temperature higher than 230 °C. Additionally, [AcMIm]FeCl4 efficiently catalysed the oxidative ipso-hydroxylation of arylboronic acids and regioselective Friedel–Crafts acylation without external organic solvent or additives, such as acids, base, and ligands. This functionalised ionic liquid, [AcMIm]FeCl4, was recycled and reused at least six times without significant loss of its catalytic properties and stability.
- Saha, Arijit,Payra, Soumen,Dutta, Dipa,Banerjee, Subhash
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p. 1129 - 1134
(2017/08/18)
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- Synthesis of phenols by using aryldiazonium silica sulfate nanocomposites
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The hydrolysis of a new type of diazonium salt immobilized on the surface of silica sulfuric acid was studied in this work. By using diazonium salt nanocomposites, a number of phenol derivatives were synthesized in good yields. In contrast to the previous works, the present procedure was conveniently carried out under mild and solvent-free conditions. The effects of solvent and temperature were studied on the dediazoniation products. The notable advantages of this methodology were operational simplicity, availability of reactants, short reaction time and easy work-up.
- Zarei, Amin,Khazdooz, Leila,Aghaei, Hamidreza,Gheisari, Mohammad Mehdi,Alizadeh, Shahrzad,Golestanifar, Laleh
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supporting information
p. 6954 - 6961
(2017/11/16)
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- Acylation of Csp2-H bond with acyl sources derived from alkynes: Rh-Cu bimetallic catalyzed CC bond cleavage
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A Rh-Cu bimetallic catalyzed o-acylation of acyloxacetamide with alkynes has been described. This transformation provides a novel, concise way to synthesize ortho-acylphenols using functionalized alkynes as acylating reagents. Mechanistic studies revealed a Rh-Cu relay process, in which O2 plays a critical role for the formation of carbonyl compounds.
- Xie, Ying
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p. 12372 - 12375
(2016/10/22)
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- Photocatalytic Hydrogen-Evolution Cross-Couplings: Benzene C-H Amination and Hydroxylation
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We present a blueprint for aromatic C-H functionalization via a combination of photocatalysis and cobalt catalysis and describe the utility of this strategy for benzene amination and hydroxylation. Without any sacrificial oxidant, we could use the dual catalyst system to produce aniline directly from benzene and ammonia, and phenol from benzene and water, both with evolution of hydrogen gas under unusually mild conditions in excellent yields and selectivities.
- Zheng, Yi-Wen,Chen, Bin,Ye, Pan,Feng, Ke,Wang, Wenguang,Meng, Qing-Yuan,Wu, Li-Zhu,Tung, Chen-Ho
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supporting information
p. 10080 - 10083
(2016/09/04)
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- Copper catalyzed oxidative deamination of Betti bases: An efficient approach for benzoylation/formylation of naphthols and phenols
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An efficient route for benzoylation or formylation of naphthols/phenols is developed via oxidative deamination of Betti bases. A copper salt catalyst with TBHP as an oxidant is used. Water is used as a reagent as well as solvent. The reaction proceeds through a regioselective radical pathway. Most importantly, the position of acylation is unambiguous. The method is also applicable to non-hydroxy substrates.
- Deb, Mohit L.,Pegu, Choitanya Dev,Borpatra, Paran J.,Baruah, Pranjal K.
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p. 40552 - 40559
(2016/05/24)
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- Concise Synthesis of 4-Arylquinolines via Intramolecular Cyclization of Allylamines and Ketones
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The intramolecular cyclization of allylamines and ketones was achieved in the presence of potassium tert-butoxide and N,N-dimethylformamide. A series of 4-arylquinolines was prepared in good yields. The reaction could be accomplished at room temperature using only a substoichiometric amount of potassium tert-butoxide. On the other hand, the reaction of the structurally analogous allyl ethers afforded diverse products. The reaction may proceed via the rearrangement of α-aminoallyl radicals and the generation of nucleophilic enamine intermediates. This finding represents a new strategy for the synthesis of quinoline derivatives from readily available 2-(allylamino)phenyl ketones.
- Wei, Wen-Tao,Cheng, Ya-Juan,Hu, Yu,Chen, Yan-Yan,Zhang, Xue-Jing,Zou, Yong,Yan, Ming
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supporting information
p. 3474 - 3478
(2016/01/25)
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- Palladium-catalyzed direct ortho aroylation of 2-phenoxypyridines with aldehydes and catalytic mechanism investigation
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A direct ortho aroylation of 2-phenoxypyridines with aldehydes leading to aryl ketones by the use of palladium(II) acetate, tert-butyl hydroperoxide, and chlorobenzene as the catalyst, oxidant, and solvent, respectively, is presented. Intra- and intermolecular kinetic isotope effects, radical trapping, and controlled experiments were carried out to support the proposed catalytic mechanism for the reaction. Syntheses of (2-hydroxyphenyl)(phenyl)methanones and 1-hydroxy-9H-fluoren-9-ones directed from ortho-aroylated 2-phenoxypyridines were demonstrated.
- Chu, Jean-Ho,Chen, Shih-Tien,Chiang, Meng-Fan,Wu, Ming-Jung
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p. 953 - 966
(2015/03/18)
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- Expedient carbonylation of aryl halides in aqueous or neat condition
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An expedient and versatile, microwave-assisted procedure for the carbonylation of aryl halides with boronic acids, alcohols or amines in water or under neat conditions has been developed. The reaction is catalyzed by fluorous, oxime-based palladacycle 1 that shows an excellent recyclable property and low levels of Pd leaching. To demonstrate the usefulness of the protocol, we applied it to the preparation of compounds of pharmaceutical interest, including a precursor of the reverse transcriptase inhibitor, niacin, benzocaine and butamben.
- Ang, Wei Jie,Lo, Lee-Chiang,Lam, Yulin
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p. 8545 - 8558
(2014/12/11)
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- Low-temperature oxidation of Methylene bridge bond in coal by model compound
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In order to find out characteristics of active structures in coal at early phase of oxidation, diphenylmethane was adopted as the model compound to study the oxidation properties of bridge bond (methylene) in coal with low-temperature experimental condition (293 K-423 K), according to structure of molecular coal. Mean while, the generated oxidation products under different reaction conditions were analyzed qualitatively via FTIR spectrometer and GC-MS. The results show that the new structures which involve C-O, C=O, Ar-O and Ar-OH are constantly generated with temperature rise in the process of low-temperature oxidation of diphenylmethane, especially after the 393 K. Besides, the phenols, benzaldehyde, diphenylmethanone, phenyl benzoate, 2-benzyl phenols and 2-phenolic-diphenylmethanone were detected in oxidation products, which demonstrated this oxidation is a multi-step reaction. Meantime, the substitution between O and H is more easily occurs in -CH2-than in benzene ring. The temperature and time are major factors which affecting low-temperature oxidation of diphenylmethane. In conclusion, this study provides reference for explaining and controlling the low-temperature oxidation of coal from chemical perspective.
- Tang, Yibo,Li, Zenghua,Tien, Jerry C.,Yin, Wenxuan,Ma, Dongjuan
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p. 795 - 798
(2014/06/09)
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- Palladium-catalyzed ortho-CH-bond oxygenation of aromatic ketones
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A palladium-catalyzed C(sp2)-H bond oxygenation reaction is described. This protocol represents the first example of a C-H bond cleavage/C-O bond formation sequence, by employing a ketone moiety as the directing group. With this new catalytic method, a variety of ortho-acylphenols can be easily accessed from arylketones.
- Choy, Pui Ying,Kwong, Fuk Yee
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supporting information
p. 270 - 273
(2013/03/13)
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- Broadening the catalyst and reaction scope of regio- and chemoselective C-H oxygenation: A convenient and scalable approach to 2-acylphenols by intriguing Rh(ii) and Ru(ii) catalysis
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A unique Rh(ii) and Ru(ii) catalyzed C-H oxygenation of aryl ketones and other arenes has been developed for the facile synthesis of diverse functionalized phenols. The reaction demonstrates excellent reactivity, regio- and chemoselectivity, good functional group compatibility and high yields. The practicality of this method has been proved by gram-scale synthesis of a few different 2-acylphenols. Its utility has been well exemplified in further applications in heterocycle synthesis and direct modifications of drug Fenofibrate.
- Shan, Gang,Han, Xuesong,Lin, Yun,Yu, Shanyou,Rao, Yu
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supporting information
p. 2318 - 2322
(2013/04/10)
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- Pd-catalyzed sp2 C-H hydroxylation with TFA/TFAA via weak coordinations
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An efficient sp2 C-H hydroxylation has been developed for the synthesis of a wide range of functionalized phenols with aryl ketones, benzoates, benzamides, acetanilides and sulfonamides through palladium(II) catalysis. A trifluoroacetic acid (TFA)/trifluoroacetic anhydride (TFAA) co-solvent system serves as the oxygen source and is the critical factor for weak coordination promoted C-H activation. Georg Thieme Verlag Stuttgart New York.
- Rao, Yu
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p. 2472 - 2476
(2013/12/04)
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- Palladium-catalyzed decarboxylative coupling of α-oxocarboxylic acids with C(sp2)-H of 2-aryloxypyridines
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An efficient palladium-catalyzed decarboxylative ortho-acylation of 2-aryloxypyridines with α-oxocarboxylic acids is described. In this new transformation, the aromatic C(sp2)-H bond was successfully acylated to give diverse aromatic ketones regioselectively in moderate to good yields. The pyridine group can be removed easily after the acylation to give the corresponding 2-hydroxy aromatic ketones. Copyright
- Yao, Jinzhong,Feng, Ruokun,Wu, Zaihong,Liu, Zhanxiang,Zhang, Yuhong
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p. 1517 - 1522
(2013/06/27)
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- Preparation of benzoyloxy benzophenone derivatives and their inhibitory effects of ICAM-1 expression
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Benzoyloxy benzophenone derivatives were prepared in 3 steps including DCC coupling, Fries rearrangement and esterification from benzoic acids in 24-89% total yields. Among the prepared 12 benzophenone analogues 1a-1l, the compound 1b having three chloro groups at the para position showed maximum inhibitory effects of ICAM-1 expression but, 1a which have no substituents at all showed no inhibitory activity. This study provides the evidences that benzoyloxy benzophenone derivative, 1b may exert its anti-inflammatory activity by suppressing IFN-γ-induced ICAM-1 expression.
- Kwon, Eun Mi,Kim, Cheol Gi,Goh, Ah Ra,Park, Jinseu,Jun, Jong-Gab
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p. 1939 - 1944
(2012/08/07)
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- Pd-catalyzed C-H oxygenation with TFA/TFAA: Expedient access to oxygen-containing heterocycles and late-stage drug modification
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Functionalized phenols are valuable industrial chemicals related to pharmaceuticals, agrochemicals, and polymers. Therefore, the direct catalytic hydroxylation of arenes to produce phenols has attracted much attention. Although tremendous progress has been made in this field, there are still difficult substrates which remain unmet challenges for direct hydroxylation in terms of regio- and chemoselectivity, as well as the practicality of current methods (Scheme 1). For example, 2-hydroxy aromatic ketones are useful synthetic intermediates for the preparation of various oxygen-containing heterocycles such as benzofuranone, chromanone, benzoxazole, and dibenzooxazepine; they also serve as key building blocks for drugs such as celiprolol, acebutolol, and propafenone. Traditional strategies for accessing 2-hydroxy aromatic ketones have mainly involved the oxidation of benzylic alcohols, the hydrolysis of aromatic halides, Fries rearrangement of esters or the demethylation of methyl phenyl ether. These methods generally suffer from one limitation or another, such as tedious reaction procedures, harsh reaction conditions, low yields, or the formation of side products. Hence, direct transformation of readily available aromatic ketones into valuable 2-hydroxylated products by transition metal-catalyzed C-H functionalization is arguably a highly efficient and atom-economic method to access these compounds. Moreover, developing a more general strategy for the regio- and chemoselective C-H oxygenation of a variety of challenging arenes would be especially desirable for phenol synthesis (Scheme 1).
- Shan, Gang,Yang, Xinglin,Ma, Linlin,Rao, Yu
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supporting information
p. 13070 - 13074
(2013/02/26)
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- Synthesis of ortho-acylphenols through the palladium-catalyzed ketone-directed hydroxylation of arenes
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ortho-Acylphenols are an important structural motif found in a diversity of bioactive molecules ranging from natural products to drugs (Figure 1). Moreover, they also serve as versatile building blocks for the synthesis of various pharmaceuticals, such as warfarin, as well as agrichemicals, flavors, and fragrances. Classic approaches to the synthesis of o-acylphenols generally involve a two-step process: acylation of phenols followed by Fries rearrangement of the resulting phenyl esters (Scheme 1a). On the other hand, direct C-acylation of phenols has also been known under more forcing conditions. Although effective, these approaches are often complicated by the formation of undesired p-substituted products when bulky acyl groups need to be introduced, as well as the limited variety of ketones that can be generated.
- Mo, Fanyang,Trzepkowski, Louis J.,Dong, Guangbin
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p. 13075 - 13079
(2013/02/25)
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- Ruthenium-catalyzed C-H bond oxygenations with weakly coordinating ketones
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Ruthenium complexes enabled first C(sp2)-H bond oxygenations of aromatic ketones with excellent functional group tolerance, and broad scope as well as high chemoselectivity and site selectivity.
- Thirunavukkarasu, Vedhagiri S.,Ackermann, Lutz
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p. 6206 - 6209
(2013/02/23)
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- An improved synthesis of hydroxy aryl ketones by fries rearrangement with methanesulfonic acid/methanesulfonic anhydride
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Methanesulfonic acid treated with methanesulfonic anhydride effectively mediates the Fries rearrangement of aryl esters to give hydroxy aryl ketones with high yields. Georg Thieme Verlag Stuttgart · New York.
- Jeon, Ingyu,Mangion, Ian K.
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experimental part
p. 1927 - 1930
(2012/10/08)
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- Benzofurans from benzophenones and dimethylacetamide: Copper-promoted cascade formation of furan O1-C2 and C2-C3 bonds under oxidative conditions
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DMA donates: Copper(II) acetate and 8-hydroxyquinoline promote the formation of a benzofuran core through a cascade of copper-catalyzed processes wherein the key carbon atom comes from the dimethylacetamide (DMA) solvent. Strong evidence for the participation of a Wacker cyclization catalyzed solely by copper is provided, not only in the title reaction from benzophenones but also from 2-hydroxy-α-arylstyrene derivatives. Copyright
- Moure, Maria J.,Sanmartin, Raul,Dominguez, Esther
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p. 3220 - 3224
(2012/05/05)
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- One-pot synthesis of 3,4-disubstituted coumarins under catalysis of Mn 3O4 nanoparticles
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The one-pot synthesis of 3,4-disubstituted coumarins from substituted 2-(hydroxymethyl)phenols with β-keto esters catalyzed by Mn 3O4 nanoparticles was developed. A series of 3,4-disubstituted coumarin derivatives were obtained in good yields. A new method for the one-pot synthesis of 3,4-disubstituted coumarins from substituted 2-(hydroxymethyl)phenols with β-keto esters catalyzed by Mn 3O4 nanoparticles has been developed. A series of 3,4-disubstituted coumarin derivatives were synthesized from substituted 2-(hydroxymethyl)phenols and β-keto esters in good yields. Copyright
- Sun, Huayin,Zhang, Yonghui,Guo, Fengfeng,Yan, Yizhe,Wan, Changfeng,Zha, Zhenggen,Wang, Zhiyong
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p. 480 - 483
(2012/03/09)
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- Rearrangement of 2-aryloxybenzaldehydes to 2-hydroxybenzophenones by rhodium-catalyzed cleavage of aryloxy C-O bonds
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Lost in the shuffle: An unprecedented rearrangement of the title compounds proceeds by the simultaneous rhodium-catalyzed cleavage of aryloxy C-O and aldehyde C-H bonds (see scheme). The reaction tolerates the presence of various catalytically reactive substituents such as aryl halides, nitrile, and esters.
- Rao, Honghua,Li, Chao-Jun
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p. 8936 - 8939
(2011/11/07)
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- Protolytic defluorination of trifluoromethyl-substituted arenes
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A series of trifluoromethyl-substituted arenes were studied in their reactions with Bronsted superacids. The products from these reactions suggest the formation of reactive electrophiles, such as carbocations, acylium cations or equivalent electrophilic species. As such, Friedel-Crafts-type reactions occur between these species and arene nucleophiles. NMR studies were done, and the results suggest the formation of an acyl group from the trifluoromethyl groups in the superacid.
- Kethe, Anila,Tracy, Adam F.,Klumpp, Douglas A.
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experimental part
p. 4545 - 4549
(2011/07/29)
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