- Mechanochemical Solvent-Free Suzuki–Miyaura Cross-Coupling of Amides via Highly Chemoselective N?C Cleavage
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Although cross-coupling reactions of amides by selective N?C cleavage are one of the most powerful and burgeoning areas in organic synthesis due to the ubiquity of amide bonds, the development of mechanochemical, solid-state methods remains a major challe
- Ma, Yangmin,Shao, Lei,Szostak, Michal,Wang, Ruihong,Zhang, Jin,Zhang, Pei
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supporting information
(2022/01/04)
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- Acylboronates in polarity-reversed generation of acyl palladium(II) intermediates
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We report a catalytic cross-coupling process between aryl (pseudo)halides and boron-based acyl anion equivalents. This mode of acylboronate reactivity represents polarity reversal, which is supported by the observation of tetracoordinated boronate and acyl palladium(II) species by 11B, 31P NMR, and mass spectrometry. A broad scope of aliphatic and aromatic acylboronates has been examined, as well as a variety of aryl (pseudo)halides.
- Trofimova, Alina,Holownia, Aleksandra,Tien, Chieh-Hung,?irvinskas, Martynas J.,Yudin, Andrei K.
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supporting information
p. 3294 - 3299
(2021/05/07)
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- STRONGLY LEWIS ACIDIC METAL-ORGANIC FRAMEWORKS FOR CONTINUOUS FLOW CATALYSIS
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Lewis acidic metal-organic framework (MOF) materials comprising triflate-coordinated metal nodes are described. The materials can be used as heterogenous catalysts in a wide range of organic group transformations, including Diels-Alder reactions, epoxide-ring opening reactions, Friedel-Crafts acylation reactions and alkene hydroalkoxylation reactions. The MOFs can also be prepared with metallated organic bridging ligands to provide heterogenous catalysts for tandem reactions and/or prepared as composites with support particles for use in columns of continuous flow reactor systems. Methods of preparing and using the MOF materials and their composites are also described.
- -
-
Paragraph 0216-0219; 0226; 0239; 0255
(2021/02/26)
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- Synthesis of two new naphthalene-containing compounds and their bindings to human serum albumin
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Two naphthalene-containing compounds, 4-hydroxy-6,7-dimethoxy-1-(4-(trifluoromethyl)phenyl)-2-naphthoic acid (A) and 4-hydroxy-6,7-dimethoxy-1-phenyl-2-naphthoic acid (B), were prepared by several steps. Their bindings to human serum albumin (HSA) were st
- Wang, Xia,Xing, Yue,Su, Jing,Wang, Changsheng,Wang, Zishi,Yu, Yinghui,Xu, Hongliang,Ma, DongSheng
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p. 3435 - 3448
(2020/07/04)
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- Water Phase, Room Temperature, Ligand-Free Suzuki–Miyaura Cross-Coupling: A Green Gateway to Aryl Ketones by C–N Bond Cleavage
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We report herein a green strategy for synthesis of aryl ketones from twisted amides by using Pd(OAc)2 as catalysts. This method shows high functional group tolerance to offer a variety of ketones in good yields under mild conditions (up to 94 %). Notably, this methodology demonstrates the first water phase, room temperature, ligand-free Suzuki–Miyaura coupling through C–N bond cleavage, which is environmentally friendly and might facilitate the development of amide based green chemistry.
- Zhang, Yuqi,Wang, Zijia,Tang, Zhao,Luo, Zhongfeng,Wu, Hongxiang,Liu, Tingting,Zhu, Yulin,Zeng, Zhuo
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p. 1620 - 1628
(2020/03/04)
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- Tunable aryl imidazolium recyclable ionic liquid with dual br?nsted-lewis acid as green catalyst for friedel-crafts acylation and thioesterification
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Unique tunable aryl imidazolium ionic liquids successfully catalyzed Friedel-Crafts acylation and thioesterification in sealed tubes. These reactions can form a C-C bond and a C-S bond with high atom economy. Ionic liquids exhibited high activity and catalyzed essential reactions with good to excellent yields while retaining their catalytic activities for recycling.
- Chen, Wen-Tin,Chou, Shih-Huan,Ho, Wen-Yueh,Hung, Ming-Wei,Lin, Michelle,Lin, Wesley,Lin, Yi-Jyun,Luo, Shun-Yuan,Reddy, Daggula Mallikarjuna,Thul, Mayur,Wu, Hsin-Ru,Wu, Yao-Peng
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- A Bifunctional Iron Nanocomposite Catalyst for Efficient Oxidation of Alkenes to Ketones and 1,2-Diketones
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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
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p. 4617 - 4629
(2020/05/19)
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- N-Acyl-5,5-Dimethylhydantoins: Mild Acyl-Transfer Reagents for the Synthesis of Ketones Using Pd-PEPPSI or Pd/Phosphine Catalysts
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N-Acyl-hydantoins have emerged as novel acyl-transfer reagents for the synthesis of ketones via selective N-C(O) cleavage. Herein, we report two new protocols for the cross-coupling of N-acyl-5,5-dimethylhydantoins using versatile and readily accessible Pd-PEPPSI or Pd/phosphine catalysts. The acyl Suzuki reactions afford biaryl ketones in good to excellent yields under operationally simple conditions using commercially available, bench- A nd air-stable twisted N-acyl-hydantoins as acyl donors. The method complements and expands on the previous protocol for the cross-coupling of N-acyl-hydantoins (Luo, Z.et al. Org. Process Res. Dev. 2018, 22, 1188).
- Liu, Chengwei,Szostak, Michal,Wang, Chang-An
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p. 1043 - 1051
(2020/07/15)
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- Decarboxylation with Carbon Monoxide: The Direct Conversion of Carboxylic Acids into Potent Acid Triflate Electrophiles
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We report a new strategy for the conversion of carboxylic acids into potent acid triflate electrophiles. The reaction involves oxidative carbonylation of carboxylic acids with I2 in the presence of AgOTf, and is postulated to proceed via acyl hypoiodites that react with CO to form acid triflates. Coupling this chemistry with subsequent trapping with arenes offers a mild, room temperature approach to generate ketones directly from broadly available carboxylic acids without the use of corrosive and reactive Lewis or Bronsted acid additives, and instead from compounds that are readily available, stable, and functional group compatible.
- Kinney, R. Garrison,Arndtsen, Bruce A.
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supporting information
p. 5085 - 5089
(2019/04/01)
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- Strongly Lewis Acidic Metal-Organic Frameworks for Continuous Flow Catalysis
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The synthesis of highly acidic metal-organic frameworks (MOFs) has attracted significant research interest in recent years. We report here the design of a strongly Lewis acidic MOF, ZrOTf-BTC, through two-step transformation of MOF-808 (Zr-BTC) secondary building units (SBUs). Zr-BTC was first treated with 1 M hydrochloric acid solution to afford ZrOH-BTC by replacing each bridging formate group with a pair of hydroxide and water groups. The resultant ZrOH-BTC was further treated with trimethylsilyl triflate (Me3SiOTf) to afford ZrOTf-BTC by taking advantage of the oxophilicity of the Me3Si group. Electron paramagnetic resonance spectra of Zr-bound superoxide and fluorescence spectra of Zr-bound N-methylacridone provided a quantitative measurement of Lewis acidity of ZrOTf-BTC with an energy splitting (?E) of 0.99 eV between the ?x? and ?y? orbitals, which is competitive to the homogeneous benchmark Sc(OTf)3. ZrOTf-BTC was shown to be a highly active solid Lewis acid catalyst for a broad range of important organic transformations under mild conditions, including Diels-Alder reaction, epoxide ring-opening reaction, Friedel-Crafts acylation, and alkene hydroalkoxylation reaction. The MOF catalyst outperformed Sc(OTf)3 in terms of both catalytic activity and catalyst lifetime. Moreover, we developed a ZrOTf-BTC?SiO2 composite as an efficient solid Lewis acid catalyst for continuous flow catalysis. The Zr centers in ZrOTf-BTC?SiO2 feature identical coordination environment to ZrOTf-BTC based on spectroscopic evidence. ZrOTf-BTC?SiO2 displayed exceptionally high turnover numbers (TONs) of 1700 for Diels-Alder reaction, 2700 for epoxide ring-opening reaction, and 326 for Friedel-Crafts acylation under flow conditions. We have thus created strongly Lewis acidic sites in MOFs via triflation and constructed the MOF?SiO2 composite for continuous flow catalysis of important organic transformations.
- Ji, Pengfei,Feng, Xuanyu,Oliveres, Pau,Li, Zhe,Murakami, Akiko,Wang, Cheng,Lin, Wenbin
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supporting information
p. 14878 - 14888
(2019/10/02)
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- Palladium-Catalyzed Direct Oxidative Coupling of Iodoarenes with Primary Alcohols Leading to Ketones: Application to the Synthesis of Benzofuranones and Indenones
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In the present study, a palladium-catalyzed direct oxidative acylation through cross-dehydrogenative coupling has been investigated, utilizing readily available primary alcohols as acylating sources. Overall, this oxidative coupling proceeds via three distinct transformations such as oxidation, radical formation, and cross-coupling in one catalytic process. This protocol does not involve the assistance of a directing group or activation of the carbonyl group by any other means. Furthermore, this reaction made use of no toxic CO gas as carbonylating agent; instead, feedstock primary alcohols have been utilized as acylation source. Notably, the synthesis of benzofuranones and indenones is enabled. This strategy was also applied to the synthesis of n-butylphthalide, fenofibrate, pitofenone, and neo-lignan.
- Suchand, Basuli,Sreenivasulu, Chinnabattigalla,Satyanarayana, Gedu
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p. 4832 - 4843
(2019/07/31)
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- A new efficient method for the preparation of intermediate aromatic ketones by Friedel–Crafts acylation
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Abstract: As the most important method to prepare pharmaceutical and chemical intermediate aromatic ketones, Friedel–Crafts (F–C) acylation is used to seek a novel catalytic system which is imminently consistent with the concept of green chemistry. In this study, six deep eutectic solvents (DES) were synthesized for the Friedel–Crafts acylation reaction as a catalytic solvent. Among the six DES, choline chloride-zinc chloride ([ChCl][ZnCl2]2) proved to be the most competent candidate of electron-rich arenes with acylation reagent. It got the highest yield when 1.0 equivalent of [ChCl][ZnCl2]2 used with acyl halides at 70?°C. Recycled DES was reused directly without any extra process. After five cycles, the catalytic activity did not decrease significantly (80–85%). Finally, according to experimental validation, the possible mechanism of this reaction was considered. Graphical Abstract: [Figure not available: see fulltext.].
- Jin, Xiaojun,Wang, Ailing,Cao, Hongyu,Zhang, Shujia,Wang, Lihao,Zheng, Xueliang,Zheng, Xuefang
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p. 5521 - 5530
(2018/04/30)
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- N-Acyl-5,5-dimethylhydantoin, a New Mild Acyl-Transfer Reagent in Pd Catalysis: Highly Efficient Synthesis of Functionalized Ketones
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The palladium-catalyzed Suzuki-Miyaura cross-coupling of N-acyl-5,5-dimethylhydantoins with arylboronic acids has been developed via selective amides C-N bond cleavage. The new reagent is commercially available and air-/moisture-stable, and it offers a variety of ketones in good yields through Suzuki coupling under mild conditions (up to 95%).
- Luo, Zhongfeng,Liu, Tingting,Guo, Weijie,Wang, Zijia,Huang, Jingjun,Zhu, Yulin,Zeng, Zhuo
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p. 1188 - 1199
(2018/09/06)
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- Acyl and Decarbonylative Suzuki Coupling of N-Acetyl Amides: Electronic Tuning of Twisted, Acyclic Amides in Catalytic Carbon-Nitrogen Bond Cleavage
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We report the Pd-catalyzed acyl and the Ni-catalyzed biaryl Suzuki-Miyaura cross-coupling of N-acetyl-amides with arylboronic acids by selective N-C(O) cleavage. Activation of the amide bond by N-acylation provides electronically destabilized, acyclic, nonplanar amide, which readily undergoes cross-coupling with a wide range of boronic acids to produce biaryl ketones or biaryls in a highly efficient manner. Most crucially, the presented results introduce N-acetyl-amides as reactive acyclic amides in the emerging manifold of transition-metal-catalyzed amide cross-coupling. The scope and origin of high selectivity are discussed. Mechanistic studies point to remodeling of amidic resonance and amide bond twist as selectivity determining features in a unified strategy for cross-coupling of acyclic amides. Structural studies, mechanistic investigations as well as beneficial effects of the N-acyl substitution on cross-coupling of amides are reported.
- Liu, Chengwei,Li, Guangchen,Shi, Shicheng,Meng, Guangrong,Lalancette, Roger,Szostak, Roman,Szostak, Michal
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p. 9131 - 9139
(2018/09/21)
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- Kumada Arylation of Secondary Amides Enabled by Chromium Catalysis for Unsymmetric Ketone Synthesis under Mild Conditions
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The synthesis of aromatic ketones by chromium-catalyzed Kumada arylation of secondary amides with organomagnesium reagents is described. This reaction was enabled by using low-cost chromium(III) salt as a precatalyst, combined with trimethylsilyl chloride
- Chen, Changpeng,Liu, Pei,Luo, Meiming,Zeng, Xiaoming
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p. 5864 - 5868
(2018/05/29)
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- Palladium-Catalyzed Suzuki-Miyaura Cross-Coupling of N-Mesylamides by N-C Cleavage: Electronic Effect of the Mesyl Group
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A general Pd-catalyzed Suzuki-Miyaura cross-coupling of N-mesylamides with arylboronic acids by selective N-C cleavage has been developed. The presented results represent the first example of a transition-metal-catalyzed cross-coupling of amides activated by an atom-economic, cheap, and benign mesyl group. The reaction delivers arylated products featuring a range of useful functional groups by chemoselective cleavage of the amide N-C bond with high efficiency. Both the scope and the origin of high selectivity are discussed. A beneficial effect of the N-mesyl substituent on the bond activation in acyclic amides is presented.
- Liu, Chengwei,Liu, Yongmei,Liu, Ruzhang,Lalancette, Roger,Szostak, Roman,Szostak, Michal
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supporting information
p. 1434 - 1437
(2017/03/23)
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- P -Selective (sp2)-C-H functionalization for an acylation/alkylation reaction using organic photoredox catalysis
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p-Selective (sp2)-C-H functionalization of electron rich arenes has been achieved for acylation and alkylation reactions, respectively, with acyl/alkylselenides by organic photoredox catalysis involving an interesting mechanistic pathway.
- Pandey, Ganesh,Tiwari, Sandip Kumar,Singh, Bhawana,Vanka, Kumar,Jain, Shailja
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supporting information
p. 12337 - 12340
(2017/11/20)
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- Acid fluorides as acyl electrophiles in suzuki–miyaura coupling
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The first palladium-catalyzed construction of ketones through Suzuki–Miyaura reaction by using acid fluorides is described. In contrast to typical acyl electrophiles such as acid chlorides, acid fluorides are uncommon acyl electrophiles to use in boron-based coupling reactions, probably due to a high level of stability toward nucleophiles. This first attempt to use acid fluorides as a coupling partner with boronic acids allowed highly functional group tolerance and a wide substrate scope while affording various ketones in effective yields.
- Ogiwara, Yohei,Sakino, Daisuke,Sakurai, Yuka,Sakai, Norio
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supporting information
p. 4324 - 4327
(2018/08/28)
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- General Method for the Suzuki-Miyaura Cross-Coupling of Primary Amide-Derived Electrophiles Enabled by [Pd(NHC)(cin)Cl] at Room Temperature
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A general, highly selective method for the room temperature Suzuki-Miyaura cross-coupling of commonly encountered primary benzamides is reported. A combination of site-selective N,N-di-Boc-activation (tert-butoxycarbonyl activation) of the amide nitrogen with practical air- and moisture-stable, well-defined, and highly reactive [Pd(NHC)(cin)Cl] (NHC = N-heterocyclic carbene; cin = cinnamyl) provides a highly effective route to biaryl ketones from primary amides in high yields. For the first time, a TON of >1000 has been achieved in amide acyl cross-coupling.
- Lei, Peng,Meng, Guangrong,Ling, Yun,An, Jie,Nolan, Steven P.,Szostak, Michal
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p. 6510 - 6513
(2017/12/26)
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- Palladium-catalyzed Suzuki-Miyaura coupling of aryl esters
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The Suzuki-Miyaura coupling is among the most important C-C bond-forming reactions available due to its reliability, chemoselectivity, and diversity. Aryl halides and pseudohalides such as iodides, bromides, and triflates are traditionally used as the electrophilic coupling partner. The expansion of the reaction scope to nontraditional electrophiles is an ongoing challenge to enable an even greater number of useful products to be made from simple starting materials. Herein, we present how an NHC-based Pd catalyst can enable Suzuki-Miyaura coupling where the C(acyl)-0 bond of aryl esters takes on the role of electrophile, allowing the synthesis of various ketone-containing products. This contrasts known reactions of similar esters that provide biaryls via nickel catalysis. The underlying cause of this mechanistic divergence is investigated by DFT calculations, and the robustness of esters compared to more electrophilic acylative coupling partners is analyzed.
- Halima, Taoufik Ben,Zhang, Wanying,Yalaoui, Imane,Hong, Xin,Yang, Yun-Fang,Houk, Kendall N.,Newman, Stephen G.
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supporting information
p. 1311 - 1318
(2017/05/16)
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- Pd-PEPPSI: A General Pd-NHC Precatalyst for Suzuki-Miyaura Cross-Coupling of Esters by C-O Cleavage
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The Suzuki-Miyaura cross-coupling of aryl esters by selective C-O bond cleavage represents a powerful methodology in organic synthesis. Here, we report that versatile, easily prepared, well-defined Pd-PEPPSI type precatalysts serve as highly reactive catalysts for the direct Suzuki-Miyaura cross-coupling of esters. Sterically and electronically diverse aryl esters couple with arylboronic acids in good to excellent yields using a single, operationally simple protocol. Kinetic studies demonstrate that the cross-coupling of aryl esters proceeds with rates similar to the cross-coupling of amides. This study strongly supports the use of well-defined Pd(II)-NHC precatalysts bearing pyridine throw-away ligands for the selective C(acyl) cleavage of bench-stable carboxylic acid derivatives. Considering the modular scaffold of Pd-NHC precatalysts, we envision that the method will be of general interest for the development of new catalysts for C-O cleavage reactions.
- Shi, Shicheng,Lei, Peng,Szostak, Michal
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p. 3784 - 3789
(2017/10/13)
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- An efficient and green method for regio- and chemo-selective Friedel-Crafts acylations using a deep eutectic solvent ([CholineCl][ZnCl2]3)
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[CholineCl][ZnCl2]3, a deep eutectic solvent between choline chloride and ZnCl2, has been used as a dual function catalyst and green solvent for the Friedel-Crafts acylation of aromatic compounds instead of using the moisture-sensitive Lewis acids and volatile organic solvents. The reactions are performed with high yields under microwave irradiation with short reaction times for the synthesis of ketones. Interestingly, indole derivatives are regioselectively acylated in the 3-position under mild conditions with high yields without NH protection. Three new ketone products are synthesized. [CholineCl][ZnCl2]3 is easily synthesized from choline chloride and zinc chloride at a low cost, with easy purification and environmentally benign compounds. [CholineCl][ZnCl2]3 can be reused up to five times without loss of catalytic activity, making it ideal in industrial processes.
- Tran, Phuong Hoang,Nguyen, Hai Truong,Hansen, Poul Erik,Le, Thach Ngoc
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p. 37031 - 37038
(2016/05/24)
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- An efficient combination of Zr-MOF and microwave irradiation in catalytic Lewis acid Friedel-Crafts benzoylation
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A zirconium-based metal-organic framework, an effective heterogeneous catalyst, has been developed for the Friedel-Crafts benzoylation of aromatic compounds under microwave irradiation. Constructed by a Zr(iv) cluster and a linker 1,4-bis(2-[4-carboxyphenyl]ethynyl)benzene (H2CPEB), the MOF, possessing large pores and high chemical stability, was appropriate for the enhancement of Lewis acid activity under microwave irradiation. The reaction studies demonstrated that the material could give high yields for a few minutes and maintain its reactivity and structure over several cycles.
- Doan, Tan L. H.,Dao, Thong Q.,Tran, Hai N.,Tran, Phuong H.,Le, Thach N.
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supporting information
p. 7875 - 7880
(2016/05/24)
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- Hexafluoro-2-propanol-Promoted Intermolecular Friedel-Crafts Acylation Reaction
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The intermolecular Friedel-Crafts acylation was carried out in hexafluoro-2-propanol to yield aryl and heteroaryl ketones at room temperature without any additional reagents.
- Vekariya, Rakesh H.,Aubé, Jeffrey
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supporting information
p. 3534 - 3537
(2016/08/16)
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- A template-free approach to nanotube-decorated polymer surfaces using 3,4-phenylenedioxythiophene (PhEDOT) monomers
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In this work, novel 3,4-phenylenedioxythiophene (PhEDOT) monomers with alkyl, branched, and aromatic substituents were synthesized and tested for their efficacy at forming surfaces with unique wetting properties and surface morphology without the aid of surfactants. Monomers with a naphthalene substituent clearly showed the highest capacity to stabilize gas bubbles (O2 or H2) formed in solution during electrodeposition from trace water, resulting in the formation of nanotubes. Variation in the resulting density, diameter, and height of nanotubes was demonstrated by varying the electropolymerization protocol, conditions, or electrolyte used. The wetting induced by the nanotube formation results in the surfaces formed having both high contact angles with water (W) and strong adhesion, despite all polymers being intrinsically hydrophilic. This one-step and easily tunable approach to nanotube formation has potential to advance applications in membrane design, water transport and harvesting, as well as sensor design.
- Szczepanski, Caroline R.,M'Jid, Inès,Darmanin, Thierry,Godeau, Guilhem,Guittard, Frédéric
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p. 17308 - 17323
(2016/11/18)
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- N-acylsaccharins: Stable electrophilic amide-based acyl transfer reagents in Pd-catalyzed Suzuki-Miyaura coupling via N-C cleavage
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The development of efficient catalytic methods for N-C bond cleavage in amides remains an important synthetic challenge. The first Pd-catalyzed Suzuki-Miyaura cross-coupling of N-acylsaccharins with boronic acids by selective N-C bond activation is reported. The reaction enables preparation of a variety of functionalized diaryl and alkyl-aryl ketones with broad functional group tolerance and in good to excellent yields. Of general interest, N-acylsaccharins serve as new, highly reactive, bench-stable, economical, amide-based, electrophilic acyl transfer reagents via acyl-metal intermediates. Mechanistic studies strongly support the amide N-C(O) bond twist as the enabling feature of N-acylsaccharins in the N-C bond cleavage.
- Liu, Chengwei,Meng, Guangrong,Liu, Yongmei,Liu, Ruzhang,Lalancette, Roger,Szostak, Roman,Szostak, Michal
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supporting information
p. 4194 - 4197
(2016/09/09)
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- Suzuki Coupling of Amides via Palladium-Catalyzed C–N Cleavage of N-Acylsaccharins
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A palladium-catalyzed cross-coupling of activated amides with arylboronic acids has been developed via C–N bond cleavage. This approach demonstrated high tolerance to a variety of alkyl, aryl, heterocyclic and vinyl substituents. Unsymmetrical ketones could be achieved in excellent yield under mild conditions with 1% catalyst loadings. (Figure presented.).
- Wu, Hongxiang,Li, Yue,Cui, Ming,Jian, Junsheng,Zeng, Zhuo
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supporting information
p. 3876 - 3880
(2016/12/16)
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- Metal-Free Intermolecular Coupling of Arenes with Secondary Amides: Chemoselective Synthesis of Aromatic Ketimines and Ketones, and N-Deacylation of Secondary Amides
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The direct transformation of common secondary amides into aromatic ketimines and aromatic ketones with C-C bond formation is described. The reaction can also be used for N-deacylation of secondary amides to release amines. This method consists of in situ amide activation with triflic anhydride and intermolecular capture of the resulting highly electrophilic nitrilium intermediate with an arene. The reaction is applicable to various kinds of secondary amides (electrophiles), but only electron-rich and moderately electron-rich arenes can be used as nucleophiles. Thanks to the use of bench stable arenes instead of reactive and basic organometallics as nucleophiles, the reaction proceeded with high chemoselectivity at the secondary amido group in the presence of a series of sensitive functional groups such as aldehyde, ketone, ester, cyano, nitro, and tertiary amido groups. The reaction can be viewed as a Friedel-Crafts-type reaction using secondary amides as acylating agents or as an intermolecular version of the Bischler-Napieralski reaction.
- Huang, Pei-Qiang,Huang, Ying-Hong,Xiao, Kai-Jiong
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p. 9020 - 9027
(2016/10/17)
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- Palladium-Catalyzed Environmentally Benign Acylation
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Recent trends in research have gained an orientation toward developing efficient strategies using innocuous reagents. The earlier reported transition-metal-catalyzed carbonylations involved either toxic carbon monoxide (CO) gas as carbonylating agent or functional-group-assisted ortho sp2 C-H activation (i.e., ortho acylation) or carbonylation by activation of the carbonyl group (i.e., via the formation of enamines). Contradicting these methods, here we describe an environmentally benign process, [Pd]-catalyzed direct carbonylation starting from simple and commercially available iodo arenes and aldehydes, for the synthesis of a wide variety of ketones. Moreover, this method comprises direct coupling of iodoarenes with aldehydes without activation of the carbonyl and also without directing group assistance. Significantly, the strategy was successfully applied to the synthesis n-butylphthalide and pitofenone.
- Suchand, Basuli,Satyanarayana, Gedu
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p. 6409 - 6423
(2016/08/16)
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- Erbium trifluoromethanesulfonate catalyzed Friedel-Crafts acylation using aromatic carboxylic acids as acylating agents under monomode-microwave irradiation
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Erbium trifluoromethanesulfonate is found to be a good catalyst for the Friedel-Crafts acylation of arenes containing electron-donating substituents using aromatic carboxylic acids as the acylating agents under microwave irradiation. An effective, rapid and waste-free method allows the preparation of a wide range of aryl ketones in good yields and in short reaction times with minimum amounts of waste.
- Tran, Phuong Hoang,Hansen, Poul Erik,Nguyen, Hai Truong,Le, Thach Ngoc
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p. 612 - 618
(2015/02/19)
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- An unusual chemoselective oxidation strategy by an unprecedented exploration of an electrophilic center of DMSO: A new facet to classical DMSO oxidation
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A conceptually new dimethyl sulfoxide (DMSO) based oxidation process without the use of any activator has been demonstrated for the oxidation of active methylenes and benzhydrols. The developed protocol utilizes the electrophilic center of DMSO for oxidation, which was unexplored before. Mechanistic investigation has confirmed that the source of oxygen is DMSO.
- Chebolu, Rajesh,Bahuguna, Ashish,Sharma, Reena,Mishra, Vivek Kumar,Ravikumar
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supporting information
p. 15438 - 15441
(2015/10/20)
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- Metal-free tandem Beckmann-electrophilic aromatic substitution cascade affording diaryl imines, ketones, amines, and quinazolines
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A cascade reaction sequence involving a Beckmann rearrangement on benzophenone oxime followed by an electrophilic aromatic substitution (EAS) on the intermediate nitrilium ion affords N-phenyl diaryl imines that may then be hydrolyzed to ketones, or reduced to the corresponding amines. Reaction with benzonitrile afforded 2,4-diphenylquinazoline through a Beckmann-Ritter-EAS cascade.
- Sarsah, Samuel R.S.,Lutz, Marlon R.,Bobb, Kailyn Chichi,Becker, Daniel P.
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supporting information
p. 5390 - 5392
(2015/09/15)
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- Metal-free efficient cross coupling of aromatic aldehydes with aryldiazonium tetrafluoroborates using DTBP as a radical initiator
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A highly efficient, metal-free, one-pot radical route to access diaryl ketones from aromatic aldehydes is reported. The protocol renders cross coupling of aromatic aldehydes with aryl diazonium tetrafluoroborates using inexpensive di-tert-butylperoxide (DTBP) as a radical initiator under mild conditions. The reaction offers a convenient alternative to the Friedel-Crafts acylation for the synthesis of diaryl ketones.
- Tripathi, Shubhangi,Singh, Sachchida N.,Yadav, Lal Dhar S.
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supporting information
p. 4211 - 4214
(2015/06/22)
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- Improvement of the Friedel-Crafts benzoylation by using bismuth trifluoromethanesulfonate in 1-butyl-3-methylimidazolium trifluoromethanesulfonate ionic liquid under microwave irradiation
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Bismuth trifluoromethanesulfonate (bismuth triflate) catalyzed the Friedel-Crafts benzoylation of activated aromatic compounds when dissolved in 1-butyl-3-methylimidazolium trifluoromethanesulfonate ([BMIM]OTf) ionic liquid. Immobilization of bismuth triflate (5 mol %) in [BMIM]OTf allowed the synthesis of aryl ketones in good to excellent yields with short reaction times under microwave irradiation. This catalytic system was easily recovered and reused several times without any significant loss of the activity.
- Hoangtran, Phuong,Bichle Do, Ngoc,Ngocle, Thach
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p. 205 - 208
(2014/01/06)
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- Microwave-assisted facile and rapid friedel-crafts benzoylation of arenes catalyzed by bismuth trifluoromethanesulfonate
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The catalytic activity of metal triflates was investigated in Friedel-Crafts benzoylation under microwave irradiation. Friedel-Crafts benzoylation with benzoyl chloride of a variety of arenes containing electron-rich and electron-poor rings using bismuth triflate under microwave irradiation is described. This method allows the preparation of aryl ketones under solventless conditions in good to excellent yields and short reaction time. Bismuth triflate was easily recovered and reused five times without significant loss of the catalytic activity.
- Tran, Phuong Hoang,Hansen, Poul Erik,Pham, Thuy Thanh,Huynh, Vy Thanh,Huynh, Vy Hieu,Thi Tran, Thao Du,Huynh, Thanh Van,Le, Thach Ngoc
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p. 2921 - 2929
(2014/10/15)
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- Design, synthesis, and fungicidal activity of novel carboxylic acid amides represented by N-benzhydryl valinamode carbamates
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Carboxylic acid amide (CAA) fungicides are an important class of agricultural fungicide with oomycete activity and low toxicity toward mammalian cells. To find CAA analogues with high activity against resistant pathogens, a series of substituted N-benzhydryl valinamide carbamate derivatives were designed and synthesized by introducing substituted aromatic rings into valinamide carbamate leads. Bioassays showed that some title compounds exhibited very good in vitro fungicidal activity against Phytophthora capsici and in vivo fungicidal activities against Pseudoperonospora cubensis. Topomer CoMFA was performed to explore the structure-activity relationship on the basis of the in vitro data. The dimethoxy substituted aromatic analogue 9e was found to display higher in vitro fungicidal activity against Phytophthora capsici than iprovalicarb but lower activity than mandipropamid, and higher in vivo fungicidal activity against Pseudoperonospora cubensis than dimethomorph at a dosage of 6.25 μg mL-1. This journal is the Partner Organisations 2014.
- Du, Xiu-Jiang,Bian, Qiang,Wang, Hong-Xue,Yu, Shu-Jing,Kou, Jun-Jie,Wang, Zhi-Peng,Li, Zheng-Ming,Zhao, Wei-Guang
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p. 5427 - 5434
(2014/07/21)
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- Hypervalent iodine mediated direct one pot transformation of aldehydes to ketones
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An environmentally benign, step economical synthesis of ketones directly from aldehydes has been developed using hypervalent iodine as an oxidant. The key features of this protocol are its mild conditions without the use of any heavy and toxic metals for the synthesis of a wide range of ketones. the Partner Organisations 2014.
- Sagara, Prateep Singh,Chebolu, Rajesh,Bahuguna, Ashish,Ravikumar
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p. 15011 - 15013
(2014/04/17)
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- SUBSTITUTED 6,7-DIALKOXY-3-ISOQUINOLINE DERIVATIVES AS INHIBITORS OF PHOSPHODIESTERASE 10 (PDE10A)
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The invention relates to compounds of formula (I) or a pharmaceutically acceptable salt thereof, wherein R', R1 through R7 and Ar are as defined herein. These compounds are useful as inhibitors of phosphodiesterase 10 (PDE10A) which are useful in treating central nervous system diseases such as psychosis and also in treating, for example, obesity, type II diabetes, metabolic syndrome, glucose intolerance, pain and ophthalmic diseases.
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Page/Page column 62; 63; 65
(2014/05/24)
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- Friedel-Crafts acylation using bismuth triflate in [BMI][PF6]
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Bismuth trifluoromethanesulfonate was found to be a good catalyst for the Friedel-Crafts acylation. Bismuth triflate immobilized in an ionic liquid was the most efficient catalytic system. Bismuth triflate in [BMI][PF6] catalyzes this reaction under microwave irradiation allowing the rapid synthesis of aryl ketones in excellent yields. The catalyst system was easily recovered and reused several times.
- Tran, Phuong Hoang,Duus, Fritz,Le, Thach Ngoc
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experimental part
p. 222 - 224
(2012/01/30)
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- Acylation of aromatic ethers using different carboxylic acid anhydrides as acylating agents in the presence of nontoxic, noncorrosive resin amberlyst 15 as a solid acid catalyst
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Friedel-Crafts acylation of aromatic ethers, anisole, 2-methoxynaphthalene, and dimethoxybenzenes with different acid anhydrides is carried out in the presence of an inexpensive and nonhazardous solid acid, Amberlyst 15. The catalyst is reusable, thus making the process environmentally friendly.
- Pande, Manoj A.,Samant, Shriniwas D.
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experimental part
p. 754 - 761
(2011/04/12)
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- Reversed-polarity synthesis of diaryl ketones via palladium-catalyzed cross-coupling of acylsilanes
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Acylsilanes serve as acyl anion equivalents in a palladium-catalyzed cross-coupling reaction with aryl bromides to give unsymmetrical diaryl ketones. Water plays a unique and crucial activating role in these reactions. High-throughput experimentation techniques provided successful reaction conditions initially involving phosphites as ligands. Ultimately, 1,3,5,7-tetramethyl-6-phenyl-2,4,8-trioxa-6-phosphaadamantane was identified as giving a longer-lived catalyst with higher turnover numbers. Its use, in conjunction with a palladacycle precatalyst, led to optimal reaction rates and yields. Scope and limitations of this novel method are presented along with initial mechanistic insight.
- Schmink, Jason R.,Krska, Shane W.
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p. 19574 - 19577
(2012/01/13)
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- Synthesis of ketones by palladium-catalysed desulfitative reaction of arylsulfinic acids with nitriles
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Palladium-catalysed desulfitative addition of arylsulfinic acids to aryl and alkyl nitriles with 2,2′-bipyridine as a ligand afforded a variety of aryl ketones via hydrolysis of ketimine intermediates.
- Miao, Tao,Wang, Guan-Wu
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supporting information; experimental part
p. 9501 - 9503
(2011/10/01)
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- Synthesis and biological activity of halophenols as potent antioxidant and cytoprotective agents
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A series of new bromophenols and chlorophenols were prepared by a practical route. The in vitro antioxidative activity of the halophenols was evaluated by the 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical-scavenging assay, and their cytoprotective activity was also tested on hydrogen peroxide (H2O2)-induced injury in human umbilical vein endothelial cells (HUVEC). All halophenols tested displayed moderate to good DPPH radical-scavenging activity, and two bromophenols, 2,3′-dibromo-4,5,6′-trihydroxydiphenylmethanone (16c) and 2,3-dibromo-4,5-dihydroxydiphenylmethanone (17c) exhibited high protective activity against H2O2-induced injury in HUVEC with EC50 values of 0.4 and 0.8 μM, respectively. The preliminary structure-activity relationships of these compounds were also investigated in order to determine the essential structures required for their bioactivities.
- Zhao, Wanyi,Feng, Xiue,Ban, Shurong,Lin, Wenhan,Li, Qingshan
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scheme or table
p. 4132 - 4134
(2010/08/20)
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- Intermolecular N-heterocyclic carbene catalyzed hydroacylation of arynes
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A formal introduction: The conceptually new N-heterocyclic carbene catalyzed formal insertion of arynes into the Cformyl-H bond of aldehydes demonstrates the compatibility of nucleophilic NHCs with electrophilic arynes. This NHC-catalyzed hydroacylation of arynes allows the conversion of aliphatic, α,β-unsaturated, and aromatic aldehydes into aryl ketones; 27 examples and a preliminary mechanistic investigation are provided. Copyright
- Biju, Akkattu T.,Glorius, Frank
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supporting information; experimental part
p. 9761 - 9764
(2011/03/16)
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- Electrocyclization-mediated approach to 2-methyltriclisine, an unnatural analog of the azafluoranthene alkaloid triclisine
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The synthesis of 2-methyltriclisine, an unnatural analog of the azafluoranthene alkaloid, triclisine, is reported. The synthesis was achieved in 10 steps and 21% overall yield from 2-bromo-3,4-dimethoxybenzaldehyde, through the intermediacy of 3,4-dimetho
- Silveira, Claudio C.,Larghi, Enrique L.,Mendes, Samuel R.,Bracca, Andrea B. J.,Rinaldi, Francieli,Kaufman, Teodoro S.
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experimental part
p. 4637 - 4645
(2009/12/07)
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- Tf2O as a rapid and efficient promoter for the dehydrative Friedel-Crafts acylation of aromatic compounds with carboxylic acids
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The Friedel-Crafts acylation of aromatic compounds with carboxylic acids was investigated in the presence of Tf2O. The reaction was carried out efficiently and very rapidly under mild reaction conditions without the need of any catalyst.
- Khodaei, Mohammd Mehdi,Alizadeh, Abdolhamid,Nazari, Ehsan
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p. 4199 - 4202
(2008/02/05)
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- Simple route to 3-(2-indolyl)-1-propanones via a furan recyclization reaction
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A simple route to 1-R-3-(2-indolyl)-1-propanones has been elaborated based on recyclization of 2-(2-aminobenzyl)furan derivatives. Being a modification of the Reissert indole synthesis, our approach employs the furan ring as a source of carbonyl function. This approach is general and allows varying of substituents in aromatic ring as well as in 3-position of indole nucleus.
- Butin, Alexander V.,Smirnov, Sergey K.,Stroganova, Tatyana A.,Bender, Wolfgang,Krapivin, Gennady D.
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p. 474 - 491
(2007/10/03)
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- Metal bis(perfluorooctanesulfonyl)amides as highly efficient Lewis acid catalysts for fluorous biphase organic reactions
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In fluorous biphase system, metal bis(perfluorooctanesulfonyl)amides are better Lewis acid catalysts than the analogous triflates toward either transesterifications, or direct esterifications, or Friedel-Crafts acylations or Baeyer-Villiger oxidations. These catalysts are selectively soluble in lower fluorous phase and can be recovered simply by phase separation. Furthermore, these catalysts can be reused without decrease of activity in most cases.
- Hao, Xiuhua,Yoshida, Akihiro,Nishikido, Joji
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p. 193 - 199
(2007/10/03)
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- Niobium pentachloride-silver perchlorate as an efficient catalyst in the Friedel-Crafts acylation and Sakurai-Hosomi reaction of acetals
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Friedel-Crafts acylation catalyzed by niobium pentachloride with silver salt is described. Aromatic compounds with Ac2O or Bz2O were smoothly converted into the corresponding ketones in good to excellent yields. This system was also applied to the Sakurai-Hosomi reaction using acetals. The reaction proceeded quite rapidly to give the desired products in excellent yields.
- Arai, Shigeru,Sudo, Yukinori,Nishida, Atsushi
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p. 4639 - 4642
(2007/10/03)
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- Hf[N(SO2C8F17)2] 4-catalyzed Friedel-Crafts acylation in a fluorous biphase system
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In a fluorous biphase system, Hf[N(SO2C8F 17)2]4 complex (1 mol %) catalyzes Friedel-Crafts acylation of aromatic compounds such as anisole, toluene and chlorobenzene, and the corresponding aromatic ketones are obtained in satisfactory to high yields. The catalyst is selectively soluble in lower fluorous phase and can be easily recovered by simple phase separation. Furthermore, the catalyst can be reused without decrease of activity in most cases.
- Hao, Xiuhua,Yoshida, Akihiro,Nishikido, Joji
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p. 2697 - 2700
(2007/10/03)
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