- Geometric and solvent effects on intramolecular phenolic hydrogen abstraction by carbonyl n,π* and π,π* triplets
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The photochemistry of a series of alkoxyacetophenone, -benzophenone, and -indanone derivatives, which contain a remote phenolic group linked to the ketone by a para,para′- or meta,meta′-oxyethyl spacer, has been studied in acetonitrile and dichloromethane
- Lathioor, Edward C.,Leigh, William J.
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- 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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- A Simple Synthetic Route to Well-Defined [Pd(NHC)Cl(1-tBu-indenyl)] Pre-catalysts for Cross-Coupling Reactions
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The development of robust, more efficient, general, easily accessible Pd(II)–NHC pre-catalysts remains a key issue in cross-coupling applications. A selection of well-defined, air and moisture stable [Pd(NHC)Cl(1-tBu-indenyl)] (NHC=IPr, IPrCl, IMes, SIMes, IPr*) pre-catalysts have been synthesized in good to excellent yields by reacting [Pd(1-tBu-indenyl)(μ-Cl)]2 and various NHC?HCl precursors in the presence of the weak base K2CO3 in green acetone. The synthesized Pd(II)-NHC derivatives displayed excellent catalytic activity in classical Suzuki-Miyaura and Buchwald–Hartwig reactions, especially when IPrCl is employed as ancillary ligand. Additionally, in the challenging Suzuki-Miyaura reaction between esters and arylboronic acids, the [Pd(IPr*)Cl(1-tBu-indenyl)] complex exhibited the optimum catalytic activity under very mild reaction conditions.
- Liu, Yaxu,Scattolin, Thomas,Gobbo, Alberto,Beli?, Marek,Van Hecke, Kristof,Nolan, Steven P.,Cazin, Catherine S. J.
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- AIBN initiated functionalization of the benzylic sp3 C[sbnd]H and C[sbnd]C bonds in the presence of dioxygen
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A sp3 C[sbnd]H bond functionalization and C[sbnd]C bond cleavage were realized by AIBN/O2 catalyst system, providing a series of benzophenones under mild reaction conditions. The mechanistic study shows that a peroxide intermediate is involved in this transformation, and in the case of diphenylmethanes, the sp3 C[sbnd]C bond is cleaved through the peroxide rearrangement, which might provides a new way to cleave relatively strong C[sbnd]C bond and be applied to more general C[sbnd]C bond activation.
- Hu, Yingying,Shao, Yu,Zhang, Shuwei,Yuan, Yuan,Sun, Zheng,Yuan, Yu,Jia, Xiaodong
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supporting information
(2021/02/01)
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- A Fast and General Route to Ketones from Amides and Organolithium Compounds under Aerobic Conditions: Synthetic and Mechanistic Aspects
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We report that the nucleophilic acyl substitution reaction of aliphatic and (hetero)aromatic amides by organolithium reagents proceeds quickly (20 s reaction time), efficiently, and chemoselectively with a broad substrate scope in the environmentally responsible cyclopentyl methyl ether, at ambient temperature and under air, to provide ketones in up to 93 % yield with an effective suppression of the notorious over-addition reaction. Detailed DFT calculations and NMR investigations support the experimental results. The described methodology was proven to be amenable to scale-up and recyclability protocols. Contrasting classical procedures carried out under inert atmospheres, this work lays the foundation for a profound paradigm shift of the reactivity of carboxylic acid amides with organolithiums, with ketones being straightforwardly obtained by simply combining the reagents under aerobic conditions and with no need of using previously modified or pre-activated amides, as recommended.
- Ghinato, Simone,Territo, Davide,Maranzana, Andrea,Capriati, Vito,Blangetti, Marco,Prandi, Cristina
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p. 2868 - 2874
(2021/01/21)
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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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- Self-Assembled 2,3-Dicyanopyrazino Phenanthrene Aggregates as a Visible-Light Photocatalyst
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In this study, 2,3-dicyanopyrazino phenanthrene (DCPP), a commodity chemical that can be prepared at an industrial scale, was used as a photocatalyst in lieu of Ru or Ir complexes in C-X (X = C, N, and O) bond-forming reactions under visible-light irradiation. In these reactions, [DCPP]n aggregates were formed in situ through physical π-πstacking of DCPP monomers in organic solvents. These aggregates exhibited excellent photo- and electrochemical properties, including a visible light response (430 nm), long excited-state lifetime (19.3 μs), high excited-state reduction potential (Ered([DCPP]n*/[DCPP]n·-) = +2.10 V vs SCE), and good reduction stability. The applications of [DCPP]n aggregates as a versatile visible-light photocatalyst were demonstrated in decarboxylative C-C cross-coupling, amidation, and esterification reactions.
- He, Min,Yu, Xiaoqiang,Wang, Yi,Li, Fei,Bao, Ming
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p. 5016 - 5025
(2021/04/12)
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- Poly(ethylene glycol) dimethyl ether mediated oxidative scission of aromatic olefins to carbonyl compounds by molecular oxygen
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A simple, and practical oxidative scission of aromatic olefins to carbonyl compounds using O2as the sole oxidant with poly(ethylene glycol) dimethyl ether as a benign solvent has been developed. A wide range of monosubstituted,gem-disubstituted, 1,2-disubstituted, trisubstituted and tetrasubstituted aromatic olefins was successfully converted into the corresponding aldehydes and ketones in excellent yields even with gram-scale reaction. Some control experiments were also conducted to support a possible reaction pathway.
- Yu, Tao,Guo, Mingqing,Wen, Simiaomiao,Zhao, Rongrong,Wang, Jinlong,Sun, Yanli,Liu, Qixing,Zhou, Haifeng
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p. 13848 - 13852
(2021/04/22)
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- Method for preparing aldehyde ketone compound through olefin oxidation
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The invention provides a method for preparing an aldehyde ketone compound by olefin oxidation, which relates to an olefin oxidative cracking reaction in which oxygen participates. The method comprises the following specific steps: in the presence of a solvent and an oxidant, carrying out oxidative cracking on an olefin raw material to obtain a corresponding aldehyde ketone product. Compared with the traditional method, the method does not need to add any catalyst or ligand, does not need to use high-pressure oxygen, has the advantages of simple and mild reaction conditions, environment friendliness, low cost, high atom economy and the like, is wide in substrate application range and high in yield, and has a wide application prospect in the aspects of synthesis of aldehyde ketone medical intermediates and chemical raw materials.
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Paragraph 0019
(2021/04/07)
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- Photo-induced oxidative cleavage of C-C double bonds of olefins in water
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The carbonyl compounds, synthesized by the oxidative cleavage of their corresponding olefins, are of great significance in organic synthesis, especially aryl ketones. We have developed a gentle and effective protocol, using acid red 94 as the organic metal-free photocatalyst, O2 as the oxidant, and water as the solvent. Under visible light irradiation, aryl ketone derivatives were obtained in moderate to excellent yields, showing good economic and environmental advantages.
- Zhang, Yilan,Yue, Xiaoguang,Liang, Chenfeng,Zhao, Jianming,Yu, Wenbo,Zhang, Pengfei
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supporting information
(2021/08/27)
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- Radical-mediated aerobic oxidation of substituted styrenes and stilbenes
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A 2,2-azobis(isobutyronitrile)-catalyzed oxidative cleavage of alkenes with molecular oxygen as the oxidant was described. Carbonyl compounds and oxiranes were obtained in moderate yield under mild conditions. This study provided useful insights into the mechanism of aerobic oxidative cleavage of alkenes.
- Aman, Hasil,Chiu, Wei-Hua,Chuang, Gary Jing,Liu, Pin-Heng
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supporting information
p. 20103 - 20106
(2021/12/02)
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- Pd-Catalysed carbonylative Suzuki-Miyaura cross-couplings using Fe(CO)5under mild conditions: generation of a highly active, recyclable and scalable ‘Pd-Fe’ nanocatalyst
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The dual function and role of iron(0) pentacarbonyl [Fe(CO)5] has been identified in gaseous CO-free carbonylative Suzuki-Miyaura cross-couplings, in which Fe(CO)5supplied COin situ, leading to the propagation of catalytically active Pd-Fe nanoparticles. Compared with typical carbonylative reaction conditions, CO gas (at high pressures), specialised exogenous ligands and inert reaction conditions were avoided. Our developed reaction conditions are mild, do not require specialised CO high pressure equipment, and exhibit wide functional group tolerance, giving a library of biaryl ketones in good yields.
- Zhu, Zhuangli,Wang, Zhenhua,Jian, Yajun,Sun, Huaming,Zhang, Guofang,Lynam, Jason M.,McElroy, C. Robert,Burden, Thomas J.,Inight, Rebecca L.,Fairlamb, Ian J. S.,Zhang, Weiqiang,Gao, Ziwei
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supporting information
p. 920 - 926
(2021/02/09)
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- Palladium nanoparticles on amino-modified silica-catalyzed C–C bond formation with carbonyl insertion
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Abstract: A practical and heterogeneously catalyzed Stille, homo-coupling, and Suzuki carbonylation reaction has been reported using Pd nanoparticles supported on amino-vinyl silica-functionalized magnetic carbon nanotube (CNT@Fe3O4@SiO2-Pd) for the efficient synthesis of symmetrical and unsymmetrical diaryl ketones from aryl iodides. A wide variety of symmetrical and unsymmetrical diaryl ketones were obtained in high yields under CO gas-free conditions using Mo(CO)6 as an efficient carbonyl source. Considering the atom economy of Ph3SnCl, less than an equimolar amount can be applied in Stille transformation, which is of great importance due to the toxicity of organotin derivatives. Moreover, no phosphine ligand and external reducing agent were necessary in these coupling carbonylation reactions. This heterogeneous Pd catalyst offers high activity with very low palladium leaching. Finally, the catalyst can be reused and recycled for six steps without loss in activity, exhibiting good example of sustainable methodology. Graphic abstract: [Figure not available: see fulltext.].
- Etemadi-Davan, Elham,Khalili, Dariush,Banazadeh, Ali Reza,Sadri, Ghazal,Arshad, Pourya
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p. 1891 - 1903
(2021/02/01)
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- Palladium(II) Complexes of a Neutral CCC-Tris(N-heterocyclic carbene) Pincer Ligand: Synthesis and Catalytic Applications
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Treatment of tris-azolium precursor 1 with palladium acetate under thermal conditions provided a CCC-pincer palladium(II) complex (2) bearing three NHCs (one imidazolylidene and two triazolylidenes) and one iodide ligand. Further treatment of complex 2 with an excess of AgSbF6 generates tris(carbene) dicationic palladium complex 3 in which the iodine ligands are exchanged with SbF6 anions and the metal center is stabilized by one acetonitrile ligand. Complexes 2 and 3 were tested in several cross coupling reactions showing high conversions under low catalyst loadings and mild reaction conditions. Additionally, complexes 2 and 3 performed well in the hydrosilylation of terminal alkynes with good selectivity toward the E-isomer.
- Angeles-Beltrán, Deyanira,Mendoza-Espinosa, Daniel,Rendón-Nava, David,Rheingold, Arnold L.
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supporting information
p. 2166 - 2177
(2021/07/20)
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- Palladium-Catalyzed Suzuki Coupling of N-Acyloxazolidinones via Selective Cleavage of C–N Bonds
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By implementing a palladium-catalyzed Suzuki coupling reaction of N-acyloxazolidinones with arylboronic acid, we herein report on the preparation of substituted diaryl ketones via selective cleavage of exocyclic C–N Bonds. The reaction was carried out under mild reaction conditions with excellent functional group compatibility in good yields (up to 93 %).
- Jian, Junsheng,He, Zhanyu,Zhang, Yuqi,Liu, Tingting,Liu, Lizhen,Wang, Zijia,Wang, Hui,Wang, Sanyong,Zeng, Zhuo
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p. 4176 - 4180
(2020/07/13)
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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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- Xantphos-ligated palladium dithiolates: An unprecedented and convenient catalyst for the carbonylative Suzuki–Miyaura cross-coupling reaction with high turnover number and turnover frequency
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Xantphos- and dithiolate-ligated macrocyclic palladium complexes as an efficient and stable catalyst for the carbonylative Suzuki–Miyaura cross-coupling reaction have been synthesized. The catalysts were characterized by 1H-nuclear magnetic resonance (NMR), CHNS (carbon, hydrogen, nitrogen, and sulfur) analysis, melting point analysis, and 31P-NMR spectroscopy. Several sensitive functional groups (e.g., –NO2, –F, –Cl, –Br, –NH2, and –CN) on the aromatic ring were well tolerated in the carbonylative Suzuki–Miyaura coupling reaction. The present palladium complexes produce six times higher turnover number (TON) and five times higher turnover frequency (TOF) compared with conventional homogeneous palladium precursors. Maximum TONs in the range of 105 to 106 and TOF in the range of 104 to 105 could be generated by a very low amount of catalyst loading (10–5?mol%).
- Gaikwad, Vinayak V.,Mane, Pravin A.,Dey, Sandip,Bhanage, Bhalchandra M.
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- Scalable Aerobic Oxidation of Alcohols Using Catalytic DDQ/HNO3
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A selective, practical, and scalable aerobic oxidation of alcohols is described that uses catalytic amounts of 2,3-dichloro-5,6-dicyano-1,4-benzoquinone (DDQ) and HNO3, with molecular oxygen serving as the terminal oxidant. The method was successfully applied to the oxidation of a wide range of benzylic, propargylic, and allylic alcohols, including two natural products, namely, carveol and podophyllotoxin. The conditions are also applicable to the selective oxidative deprotection of p-methoxybenzyl ethers.
- Arseniyadis, Stellios,Clavier, Louis,Copin, Chloé,Fournier, Jean,Giffard, Jean-Fran?ois,Jean, Alexandre,Katsina, Tania,Macedo Portela Da Silva, Nayane,Tamion, Rodolphe
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supporting information
p. 856 - 860
(2020/07/14)
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- Palladium-Catalyzed Amide N-C Hiyama Cross-Coupling: Synthesis of Ketones
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N-Acylglutarimides and arylsiloxanes reacted in the presence of Pd(OAc)2/PCy3, Et3N·3HF, and LiOAc to provide the corresponding arylketones in good yields. Aryl-, vinyl-, and alkyl-substituted N-acylglutarimides showed good activity in the coupling reactions of arylsiloxanes. The reaction had a broad substrate scope and showed good functional group tolerance. N-Benzoylsuccinimide and N-protected N-phenylbenzamides showed good activities in coupling reactions with phenylsiloxane. The employment of CuF2 as an activor afforded the decarbonylative products at 160 °C.
- Idris, Muhammad Aliyu,Lee, Sunwoo
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supporting information
p. 9190 - 9195
(2020/11/18)
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- Silylcarboxylic Acids as Bifunctional Reagents: Application in Palladium-Catalyzed External-CO-Free Carbonylative Cross-Coupling Reactions
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A palladium-catalyzed external-CO-free carbonylative Hiyama-Denmark cross-coupling reaction is presented. The introduction of silylcarboxylic acids as bifunctional reagents (CO and nucleophile source) avoids the need for external gaseous CO and a silylarene coupling partner. The transformation features high functional group tolerance and it is successful with electron-rich, -neutral, and -poor aryl iodides. Stoichiometric studies and control experiments provide insight into the reaction mechanism and support the hypothesized dual role of silylcarboxylic acids. (Figure presented.).
- Li, Xiong,Xu, Jie,Li, Yue,Kramer, S?ren,Skrydstrup, Troels,Lian, Zhong
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supporting information
p. 4078 - 4083
(2020/07/30)
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- Synthesis of biaryl ketones by arylation of Weinreb amides with functionalized Grignard reagents under thermodynamic controlvs.kinetic control ofN,N-Boc2-amides
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A highly efficient method for chemoselective synthesis of biaryl ketones by arylation of Weinreb amides (N-methoxy-N-methylamides) with functionalized Grignard reagents is reported. This protocol offers rapid entry to functionalized biaryl ketones after Mg/halide exchange with i-PrMgCl·LiCl under operationally-simple and practical reaction conditions. The scope of the method is highlighted in >40 examples, including bioactive compounds and pharmaceutical derivatives. Collectively, this transition-metal-free approach offers a major advantage over the recently established cross-coupling of amides by oxidative addition of N-C(O) bonds. Considering the utility of amide acylation reactions in modern synthesis, we expect that this method will be of broad interest.
- Li, Guangchen,Szostak, Michal
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supporting information
p. 3827 - 3831
(2020/06/03)
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- Kinetically Controlled, Highly Chemoselective Acylation of Functionalized Grignard Reagents with Amides by N?C Cleavage
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The direct transition-metal-free acylation of amides with functionalized Grignard reagents by highly chemoselective N?C cleavage under kinetic control has been accomplished. The method offers rapid and convergent access to functionalized biaryl ketones through transient tetrahedral intermediates. The direct access to functionalized Grignard reagents by in situ halogen–magnesium exchange promoted by the versatile turbo-Grignard reagent (iPrMgCl?LiCl) permits excellent substrate scope with respect to both the amide and Grignard coupling partners. These reactions enable facile, operationally simple and chemoselective access to tetrahedral intermediates from amides under significantly milder conditions than chelation-controlled intermediates. This novel direct two-component coupling sets the stage for using amides as acylating reagents in an alternative paradigm to the metal-chelated approach, acyl metals and Weinreb amides.
- Li, Guangchen,Szostak, Michal
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supporting information
p. 611 - 615
(2020/01/02)
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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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- Suzuki-Miyaura Cross-Coupling of Amides using Well-Defined, Air-Stable [(PR3)2Pd(II)X2] Precatalysts
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A versatile method for the Suzuki-Miyaura cross-coupling of amides using highly active, well-defined, and air-stable Pd?phosphine precatalysts is reported. Most notably, the method represents the first example of using practical and operationally-simple Pd(II)?phosphine precatalysts in the emerging amide bond cross-coupling manifold. The reactions are efficient at 0.10 mol% loading, furnishing biaryl ketones with high chemoselectivity for N?C(O) bond cleavage. This versatile method enables for the first time to achieve Pd?phosphine-catalyzed cross-coupling of amides at ppm loading. This C?N cross-coupling can be used to efficiently furnish pharmaceutical intermediates by orthogonal Pd-catalyzed cross-couplings. We fully expect that operationally-simple [(PR3)2Pd(II)X2] precatalysts as effective triggers for N?C(O) cross-coupling will be of broad synthetic and catalytic interest. (Figure presented.).
- Li, Guangchen,Ma, Siyue,Szostak, Michal,Zhou, Tongliang
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supporting information
(2020/05/26)
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- Chemoselective Synthesis of Aryl Ketones from Amides and Grignard Reagents via C(O)-N Bond Cleavage under Catalyst-Free Conditions
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Conversion of a wide range of N-Boc amides to aryl ketones was achieved with Grignard reagents via chemoselective C(O)-N bond cleavage. The reactions proceeded under catalyst-free conditions with different aryl, alkyl, and alkynyl Grignard reagents. α-Ketoamide was successfully converted to aryl diketones, while α,β-unsaturated amide underwent 1,4-addition followed by C(O)-N bond cleavage to provide diaryl propiophenones. N-Boc amides displayed higher reactivity than Weinreb amides with Grignard reagents. A broad substrate scope, excellent yields, and quick conversion are important features of this methodology.
- Sureshbabu, Popuri,Azeez, Sadaf,Muniyappan, Nalluchamy,Sabiah, Shahulhameed,Kandasamy, Jeyakumar
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p. 11823 - 11838
(2019/10/02)
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- Selective C?N Bond Cleavage of N-Acylisatins: Towards High Performance Acylation/Arylation/Transamination Reagents
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New multipurpose arylation/acylation/transamination reagents, N-acylisatins, have been developed by selective ‘inside-outside’ C?N bond cleavage under different catalytic conditions. As activated amides, N-acylisatins undergo Rh-catalyzed C?H arylation and Pd-catalyzed acylation by cleavage outside the C?N bond, and the desired biaryls and diaryl ketones were obtained in good to excellent yields. Generally, the combination of N-acylisatins with amines leads to a ring-opening reaction and formation of transamination products in a predictable manner through inside C?N bond cleavage. Interestingly, treatment of N-acylisatins with amines lead to unexpected outer-ring transamination products when CsF is added, which shows that CsF can favor the outside C?N bond cleavage path. Notably, this work presents a new strategy for multiple chemical transformations of a single amide to achieve various products by selective C?N bond cleavage. (Figure presented.).
- Xiong, Li,Deng, Rong,Liu, Tingting,Luo, Zhongfeng,Wang, Zijia,Zhu, Xiao-Feng,Wang, Hui,Zeng, Zhuo
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p. 5383 - 5391
(2019/11/03)
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- Carbonylative Suzuki coupling and alkoxycarbonylation of aryl halides using palladium supported on phosphorus-doped porous organic polymer as an active and robust catalyst
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Developing highly active catalysts with the combined advantages of molecular and solid catalysis is considered as the “Holy Grail” in the area of catalysis research. Herein, a phosphorus-doped porous polymer-immobilized palladium was successfully developed as an efficient, robust, and recyclable catalyst for the carbonylative Suzuki coupling and alkoxycarbonylation reactions of aryl halides. Rather than just as an immobilizing molecular catalyst, palladium supported on phosphorus-doped porous organic polymer exhibits even better catalytic performances than that of its analogue homogeneous catalysts in both carbonylation reactions. Moreover, the catalyst can be easily separated and reused for at least 5 times without significant loss in reactivity. Importantly, the catalyst was highly stable under carbonylation reaction conditions, and no palladium nanoparticle was observed even after the 5th reuse.
- Wan, Yali,Song, Fangxiang,Ye, Tao,Li, Guangxing,Liu, Dingfu,Lei, Yizhu
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- Ketone Synthesis by a Nickel-Catalyzed Dehydrogenative Cross-Coupling of Primary Alcohols
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An intermolecular coupling of primary alcohols and organotriflates has been developed to provide ketones by the action of a Ni(0) catalyst. This oxidative transformation is proposed to occur by the union of three distinct catalytic cycles. Two competitive oxidation processes generate aldehyde in situ via hydrogen transfer oxidation or (pseudo)dehalogenation pathways. As aldehyde forms, a Ni-catalyzed carbonyl-Heck process enables formation of the key carbon-carbon bond. The utility of this rare alcohol to ketone transformation is demonstrated through the synthesis of diverse complex and bioactive molecules.
- Verheyen, Thomas,Van Turnhout, Lars,Vandavasi, Jaya Kishore,Isbrandt, Eric S.,De Borggraeve, Wim M.,Newman, Stephen G.
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supporting information
(2019/05/08)
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- Ketone Synthesis by a Nickel-Catalyzed Dehydrogenative Cross-Coupling of Primary Alcohols
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An intermolecular coupling of primary alcohols and organotriflates has been developed to provide ketones by the action of a Ni(0) catalyst. This oxidative transformation is proposed to occur by the union of three distinct catalytic cycles. Two competitive oxidation processes generate aldehyde in situ via hydrogen transfer oxidation or (pseudo)dehalogenation pathways. As aldehyde forms, a Ni-catalyzed carbonyl-Heck process enables formation of the key carbon-carbon bond. The utility of this rare alcohol to ketone transformation is demonstrated through the synthesis of diverse complex and bioactive molecules.
- Verheyen, Thomas,Van Turnhout, Lars,Vandavasi, Jaya Kishore,Isbrandt, Eric S.,De Borggraeve, Wim M.,Newman, Stephen G.
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supporting information
p. 6869 - 6874
(2019/05/10)
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- Well-Defined, Air-Stable, and Readily Available Precatalysts for Suzuki and Buchwald-Hartwig Cross-coupling (Transamidation) of Amides and Esters by N-C/O-C Activation
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A general class of well-defined, air-stable, and readily available Pd(II)-NHC precatalysts (NHC = N-heterocyclic carbene) for Suzuki and Buchwald-Hartwig cross-coupling of amides (transamidation) and esters by selective N-C/O-C cleavage is reported. Since these precatalysts are highly active and the easiest to synthesize, the study clearly suggests that [Pd(NHC)(acac)Cl] should be routinely included during the development of new cross-coupling methods. An assay for in situ screening of NHC salts in this cross-coupling manifold is presented.
- Zhou, Tongliang,Li, Guangchen,Nolan, Steven P.,Szostak, Michal
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supporting information
p. 3304 - 3309
(2019/05/10)
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- Ligand-free Palladium-Catalyzed Carbonylative Suzuki Coupling of Aryl Iodides in Aqueous CH3CN with Sub-stoichiometric Amount of Mo(CO)6 as CO Source
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A new method for the synthesis of diaryl and heterodiaryl ketones has been established based on the palladium-catalyzed carbonylative Suzuki coupling approach with sub-stoichiometric Mo(CO)6 as CO source. Using 0.5 mol% of Pd(TFA)2 as catalyst, 0.5 equivalent of Mo(CO)6 as solid carbonyl reagent and 3 equivalent of K3PO4 as base, a wide range of functionalized (hetero)aryl iodides and (hetero)aryl boronic acids could smoothly proceed the carbonylative cross-coupling reaction in aqueous CH3CN at 50 °C, affording the corresponding ketones in good to excellent yields. The newly developed method was easy to operate under mild conditions with high efficiency. (Figure presented.).
- Sun, Nan,Sun, Qingxia,Zhao, Wei,Jin, Liqun,Hu, Baoxiang,Shen, Zhenlu,Hu, Xinquan
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p. 2117 - 2123
(2019/03/28)
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- Continuous flow synthesis of diaryl ketones by coupling of aryl Grignard reagents with acyl chlorides under mild conditions in the ecofriendly solvent 2-methyltetrahydrofuran
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An efficient continuous flow sequential synthesis of diaryl ketones was achieved by coupling of aryl Grignard reagents with acyl chlorides in the bio-derived “green” solvent 2-methyltetrahydrofuran (2-MeTHF) under mild reaction conditions (ambient temperature, 1 hour), allowing a safe and on-demand generation of 2-(3-benzoylphenyl)propionitrile with a productivity of 3.16 g hour?1
- Zhang, Chuan-Tao,Zhu, Rui,Wang, Zheng,Ma, Bing,Zajac, Adrian,Smiglak, Marcin,Xia, Chun-Nian,Castle, Steven L.,Wang, Wen-Long
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p. 2199 - 2204
(2019/01/26)
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- Hydroxyl-functionalized triazolylidene-based PEPPSI complexes: Metallacycle formation effect on the Suzuki coupling reaction
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We report the preparation and full characterization of a series of hydroxyl functionalized 1,2,3-triazolylidene-based PEPPSI complexes 2a-c and their catalytic application in the Suzuki cross coupling reaction of aryl chlorides/amides with boronic acids. Under basic reaction conditions, complexes 2a-c show a notable increase in their catalytic efficiency compared with two ether-wingtip functionalized PEPPSI analogues (3 and 4) and a commercially available NHC-Pd complex (5). The catalytic results suggest that deprotonation of the hydroxyl group in complexes 2a-c plays an important role in the overall process. Deprotonation of the alcohol moiety of complexes 2a-b with sodium tert-butoxide allows for the isolation of metallacycles 6a-b, which are proposed as the active species of cross coupling reactions.
- Rendón-Nava, David,álvarez-Hernández, Alejandro,Rheingold, Arnold L.,Suárez-Castillo, Oscar R.,Mendoza-Espinosa, Daniel
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supporting information
p. 3214 - 3222
(2019/03/13)
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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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- Highly efficient synthesis of aryl ketones by PEPPSI-palladium catalyzed acylative Suzuki coupling of amides with diarylborinic acids
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An improved acylative cross-coupling of various N-methyl-N-tosyl amides with diarylborinic acids for synthesis of aryl ketones is developed. In most cases, aryl ketones could be obtained in excellent yields by using 1 mol% 2,6-diisopropylphenylimidazolylidene and 3-chloropyridine co-supported palladium chloride as catalyst in the presence of 3 equiv. K2CO3 as base in refluxing THF. The readily prepared and cost-effective substrates, N-methyl-N-tosylamides and diarylborinic acids, and the commercially available catalyst system promise a practical and efficient access to aryl ketones.
- Wang, Chen,Huang, Lingyun,Wang, Fengze,Zou, Gang
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p. 2299 - 2301
(2018/05/16)
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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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- N-heterocyclic carbene palladium(II)-catalyzed Suzuki-Miyaura cross coupling of N-acylsuccinimides by C-N cleavage
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An easily prepared, well-defined N-heterocyclic carbene-palladium(II) complex was found to be an efficient catalyst for the Suzuki-Miyaura cross-coupling of N-acylsuccinimides with arylboronic acids via C-N bond activation. Under the optimal conditions, a
- Guo, Han,Guo, Jiarui,Jia, Dingli,Liu, Lantao,Wang, Hengjin,Wang, Tao,Zhang, Wen
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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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- Method of utilizing continuous flow microreactor to synthesize benzophenone derivative
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The invention belongs to the technical field of organic synthesis, and particularly relates to a method of utilizing a continuous flow microreactor to synthesize a benzophenone derivative. The methodincludes: using aryl Grignard reagent and acyl chloride as raw materials; at normal temperature, continuously synthesizing the benzophenone derivative in the microreactor; recycling a reaction solvent2-methyl tetrahydrofuran. Problems of environmental pollution and reaction operation safety caused by the fact that conventional Fridel-Crafts reaction is excessively dependent on reagents like aluminum trichloride, ferric trichloride and zinc dichloride are avoided, the defect that novel catalytic processes are expensive in catalytic reagent and harsh in operation condition is made up, and continuous synthesis of a medical intermediate ketoprofen nitrile is realized efficiently. The method has the advantages of high operation convenience, high reaction safety, high yield, high efficiency andreaction solvent reusability and is environment-friendly and efficient.
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Paragraph 0041-0044; 0046
(2018/09/11)
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- Pd-Catalyzed Suzuki–Miyaura Cross-Coupling of Arylboronic Acids and α-Iminonitriles through C–CN Bond Activation
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A Pd-catalyzed Suzuki–Miyaura cross-coupling reaction between arylboronic acids and α-iminonitriles has been developed. The reaction proceeds through selective activation of the C–CN bond, tolerates a wide range of substituents, and delivers the versatile ketone products in moderate to excellent yields.
- Liu, Kui,Tao, Shou-Wei,Qian, Chun,Zhu, Yong-Ming
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supporting information
p. 4769 - 4775
(2018/09/06)
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- Synthesis of some ketones via nano-nickel oxide catalyzed acylation of arylzinc reagents; strategy involving the use of mixed (methyl)(aryl)zincs
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Nano-NiO catalyzed acylation of mixed (methyl)(aryl)zincs with aromatic acyl halides in THF at room temperature provides a new facile route for aryl–aroyl coupling. Among NiCl2 .L2 and NiCl2 .L (L = monodentate and bidentate phosphine ligand) catalysts, the lower catalyst loading of NiCl2 (dppf) may seem attractive; however, nano-NiO, being the lowest cost catalyst, is more favorable for aroylation of (methyl)(aryl)zincs. This procedure also provides a supplement to Cu and Pd catalyzed acylation of diorganozincs.
- Pekel, ?zgen ?MüR,Erdik, Ender,Kalkan, Melike
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p. 759 - 767
(2018/06/07)
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- Ni/Ti Dual Catalytic Cross-Coupling of Nitriles and Organobromides to Access Ketones
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Herein, we report the development of a dual catalytic approach for the cross-coupling of nitriles with aryl- and aliphatic-bromides. A titanium(III) catalyst is used to activate nitriles enabling their coupling with organobromides through a nickel catalyst. The Ni/Ti system efficiently prepared unsymmetrical ketones with good chemoselectivity and could selectively couple a bromide in the presence of other functionalizable handles.
- Chenniappan, Vinoth Kumar,Silwal, Sajan,Rahaim, Ronald J.
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p. 4539 - 4544
(2018/05/23)
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- Suzuki-Miyaura Cross-Coupling of N-Acylpyrroles and Pyrazoles: Planar, Electronically Activated Amides in Catalytic N-C Cleavage
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The formation of C-C bonds from amides by catalytic activation of the amide bond has been thus far possible by steric distortion. Herein, we report the first example of a general Pd-catalyzed Suzuki-Miyaura cross-coupling of planar amides enabled by the combination of (i) electronic-activation of the amide nitrogen in N-acylpyrroles and pyrazoles and (ii) the use of a versatile Pd-NHC catalysis platform. The origin and selectivity of forming acylmetals, including the role of twist, are discussed.
- Meng, Guangrong,Szostak, Roman,Szostak, Michal
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p. 3596 - 3599
(2017/07/15)
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- Carbonylative Suzuki Coupling Reaction Catalyzed by a Hydrospirophosphorane Palladium Complex
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A Pd complex with the H-spirophosphorane ligand, PdCl2{P(OCMe2CMe2O)OC6H4NH2} (Cat. 1), was used as the catalyst in the carbonylative Suzuki coupling of substituted iodobenzenes with arylboronic acids and with sodium tetraphenylborate. Substituted diarylketones were obtained in good to excellent yields and a selectivity over 95 % under 1 atm of CO with 1.5 mol % of the catalyst. The promoting role of the H-spirophosphorane ligand in the catalytic process was evidenced. We used X-ray photoelectron spectroscopy, TEM, and 31P NMR spectroscopy to reveal that during the reaction Cat. 1 undergoes transformation into Pd complexes that bear the spirophosphorane ligand or other P ligands formed by its dealkylation and to Pd nanoparticles. All these Pd species contribute to the high productivity of the system.
- Wójcik, Przemys?aw,Sygellou, Labrini,Gniewek, Andrzej,Skar?yńska, Anna,Trzeciak, Anna
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p. 4397 - 4409
(2017/11/21)
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- Synthesis and structural characterization of Pd(II) thiosemicarbazonato complex: Catalytic evaluation in synthesis of diaryl ketones from aryl aldehydes and arylboronic acids
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A simple route to synthesize triphenylphosphinopalladium(II) thiosemicarbazonato complex has been described. Elemental analysis, spectral (IR, NMR) and single crystal X-ray diffraction techniques were employed for the complete characterization of the complex. The latter was found to be effective catalyst for carbon–carbon cross-coupling reaction of aryl- and heteroarylboronic acids with aromatic and heteroaromatic aldehydes to form the corresponding diaryl ketones. The influence of reaction parameters such as solvent, base, reaction temperature and catalyst loading was also investigated.
- Prabhu, Rupesh Narayana,Ramesh, Rengan
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supporting information
p. 405 - 409
(2017/01/10)
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- Ni-Catalyzed Reductive Cross-Coupling of Amides with Aryl Iodide Electrophiles via C-N Bond Activation
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A Ni-catalyzed reductive cross-coupling reaction between two electrophiles, amides and aryl iodides, has been developed. This work is the first example using amide as an electrophile to couple with another electrophile, instead of using highly basic and pyrophoric nucleophiles. Furthermore, the Ni catalyst chemoselectively inserting the C-N bond of amide triggered the reductive cross-coupling reaction, which solves the problem that the Ni catalyst preferentially inserts the more reactive C-I bond to form a self-coupling product.
- Ni, Shengyang,Zhang, Wenzhong,Mei, Haibo,Han, Jianlin,Pan, Yi
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p. 2536 - 2539
(2017/05/24)
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- N-Acylsuccinimides: Efficient acylative coupling reagents in palladium-catalyzed Suzuki coupling via C–N cleavage
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An acylative Suzuki coupling of activated amides with aryl boronic acids has been reported via palladium-catalyzed C–N bond cleavage. This protocol demonstrate amides can be activated by an atom-economic and cheap succinimide, which can be efficiently utilized to synthesize broad array of diaryl ketones in moderate to good yields.
- Cui, Ming,Chen, Zeyu,Liu, Tingting,Wang, Hui,Zeng, Zhuo
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p. 3819 - 3822
(2017/09/15)
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- Palladium Catalyzed Carbonylative Coupling for Synthesis of Arylketones and Arylesters Using Chloroform as the Carbon Monoxide Source
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We describe a modular, palladium catalyzed synthesis of aryl(hetero)aryl benzophenones and aryl benzoates from aryl(hetero)aryl halides using CHCl3 as the carbonyl source in the presence of KOH. The reaction occurs in tandem through an initial carbonylation to generate an aroyl halide, which undergoes coupling with arylboronic acids, bornonates, and phenols. Direct carbonylative coupling of indoles at the third position has also been accomplished under slightly modified reaction conditions by in situ activation of the C-H bond. Notably, CHCl3 is a convenient and safe alternation of CO gas, provides milder reaction conditions with high functional group tolerance, and gives the products in moderate to good yields.
- Sharma, Poonam,Rohilla, Sandeep,Jain, Nidhi
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p. 1105 - 1113
(2018/06/18)
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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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- 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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- The second aryl ketone compounds
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The invention provides a synthetic method for diaryl ketone compounds. The method comprises the following steps: adding ester derivatives of raw material diaryl methanol, DDQ and water into an organic solvent, carrying out stirring, then carrying out heating to 110 to 140 DEG C and carrying out reaction for 0.5 to 12 h, and subjecting obtained reaction liquid to after-treatment so as to obtain the diaryl ketone compounds, wherein the ester derivatives of the raw material diaryl methanol have a structural formula as shown in a formula (V), (VI), (VII) or (VIII), and one-to-one correspondingly obtained products have the structural formula as shown in the formula (I), (II), (III) or (IV). The synthetic method for the diaryl ketone compounds provided by the invention has the advantages of simple, convenient and safe operation, mild reaction conditions and high product selectivity.
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Paragraph 0053-0062
(2017/08/24)
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