cas 58861-53-3, 2-(4-Fluorophenyl)pyridine

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Photoactivated Functionizable Tetracarbonyl(phenylpyridine)manganese(I) Complexes as CO-Releasing Molecules: A Direct Suzuki–Miyaura Cross-Coupling on a Thermally Stable CO-RM
A new class of carbon monoxide-releasing molecules (CO-RMs) are reported based on a previously known tetracarbonyl phenylpyridine manganese(I) motif. A pre-functionalized CO-RM undergoes a direct Pd-catalysed Suzuki–Miyaura cross-coupling with phenylboronic acid to give a π-extended three-ring CO-RM. Cross-coupling conditions were modified to allow coupling of a morpholine-containing boronic acid on to a CO-RM, introducing drug-like functionality. An LED system was used to facilitate controlled CO-release. Irradiation using an LED (400 nm or 365 nm) gives rise to faster CO-release, with lower overall input power than traditional use of a TLC lamp (365 nm), as measured by an assay based on the conversion of deoxymyoglobin to carbonmonoxymyoglobin.
Ward, Jonathan S.,Bray, Joshua T. W.,Aucott, Benjamin J.,Wagner, Conrad,Pridmore, Natalie E.,Whitwood, Adrian C.,Moir, James W. B.,Lynam, Jason M.,Fairlamb, Ian J. S.
p. 5044 - 5051
(2016)
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Highly efficient phosphorescent organic light-emitting diodes based on novel bipolar iridium complexes with easily-tuned emission colors by adjusting fluorine substitution on phenylpyridine ligands
Two new phenylpyridine derivative-based heteroleptic iridium complexes, (Fppy)2Ir(dipg) (Fppdg) and (CF3ppy)2Ir(dipg) (tFmppdg) with emission peaks of 545 nm and 581 nm, respectively, were designed and synthesized by incorporation of a dipg group (N,N′-diisopro-guanidinate) as the ancillary ligand. Their photophysical, thermal, electrochemical and electroluminescence properties were investigated. The results indicate that the emitting color of phosphorescent complexes can be tuned easily by adjusting their F/CF3-substituted cyclometalated ligands. Simultaneously, Fppdg and tFmppdg show good thermal stabilities, short lifetimes of the triplet state and high photoluminescence quantum yields. More importantly, their almost complete spatial separation of HOMO and LUMO distributions endows both phosphors with an amazing bipolar charge transporting ability, and thus the corresponding doped OLEDs possess desirable concentration-independent and negligible efficiency roll-off features: at a rather wide concentration range of 8-25% doped in the CBP host, both phosphors realize a very high peak external quantum efficiency (EQE) level of >20%, and maintain values of >18% at a practical luminance of 1000 cd m?2
Chen, Shuonan,Gai, Xi,Liang, Jie,Liu, Yu,Wang, Yue,Ye, Kaiqi
p. 8329 - 8336
(2021/07/13)

Access to Branched Allylarenes via Rhodium(III)-Catalyzed C-H Allylation of (Hetero)arenes with 2-Methylidenetrimethylene Carbonate
A rhodium(III)-catalyzed C-H allylation of (hetero)arenes by using 2-methylidenetrimethylene carbonate as an efficient allylic source has been developed for the first time. Five different directing groups including oxime, N-nitroso, purine, pyridine, and pyrimidine were compatible, delivering various branched allylarenes bearing an allylic hydroxyl group in moderate to excellent yields.
Zhang, Shang-Shi,Zheng, Yi-Chuan,Zhang, Zi-Wu,Chen, Shao-Yong,Xie, Hui,Shu, Bing,Song, Jia-Lin,Liu, Yan-Zhi,Zeng, Yao-Fu,Zhang, Luyong
supporting information
p. 5719 - 5723
(2021/08/16)

Rhodium-Catalyzed Additive-Free C?H Ethoxycarbonylation of (Hetero)Arenes with Diethyl Dicarbonate as a CO Surrogate
A rhodium-catalyzed C(sp2)-H ethoxycarbonylation of indoles and arylpyridines using diethyl dicarbonate was developed. The catalytic process features an additive-free ethoxycarbonylation reaction, in which only ethanol and CO2 are produced as byproducts, providing a CO-free and operationally simple protocol. The introduced ethoxycarbonyl group is easily transformed into other ester and amide functionalities in a single step. Moreover, the reaction can be successfully applied on gram scale, and allows for the efficient synthesis of indole-2-carboxylic acid esters and isophthalates.
Kawai, Yuya,Liao, Yumeng,Matsuda, Takanori,Suzuki, Hirotsugu
supporting information
p. 4938 - 4942
(2021/09/30)

Desulfonative Suzuki–Miyaura Coupling of Sulfonyl Fluorides
Sulfonyl fluorides have emerged as powerful “click” electrophiles to access sulfonylated derivatives. Yet, they are relatively inert towards C?C bond forming transformations, notably under transition-metal catalysis. Here, we describe conditions under which aryl sulfonyl fluorides act as electrophiles for the Pd-catalyzed Suzuki–Miyaura cross-coupling. This desulfonative cross-coupling occurs selectively in the absence of base and, unusually, even in the presence of strong acids. Divergent one-step syntheses of two analogues of bioactive compounds showcase the expanded reactivity of sulfonyl fluorides to encompass both S?Nu and C?C bond formation. Mechanistic experiments and DFT calculations suggest oxidative addition occurs at the C?S bond followed by desulfonation to form a Pd-F intermediate that facilitates transmetalation.
Bahadori, Maryam,Brykczyńska, Daria,Chatelain, Paul,Moran, Joseph,Muller, Cyprien,Rowley, Christopher N.,Sau, Abhijit
supporting information
p. 25307 - 25312
(2021/10/25)

Nickel-Catalyzed Reductive 2-Pyridination of Aryl Iodides with Difluoromethyl 2-Pyridyl Sulfone
A novel nickel-catalyzed reductive cross-coupling between aryl iodides and difluoromethyl 2-pyridyl sulfone (2-PySO2CF2H) enables C(sp2)-C(sp2) bond formation through selective C(sp2)-S bond cleavage, which demonstrates the new reactivity of 2-PySO2CF2H reagent. This method employs readily available nickel catalyst and sulfones as cross-electrophile coupling partners, providing facile access to biaryls under mild reaction conditions without pregeneration of arylmetal reagents.
Miao, Wenjun,Ni, Chuanfa,Xiao, Pan,Jia, Rulong,Zhang, Wei,Hu, Jinbo
supporting information
p. 711 - 715
(2021/01/26)

Meta-dehydrogenative alkylation of arenes with ethers, ketones, and esters catalyzed by ruthenium
A meta-dehydrogenative alkylation of arenes with cyclic ethers, ketones, and esters catalyzed by ruthenium is achieved in the presence of a di-tert-butyl peroxide (DTBP) oxidant. Interestingly, when quinoline and isoquinoline are employed as the directing group, or a chain ether as alkylation reagent, the system produces Minisci reaction products. Mechanistic study indicates that meta-dehydrogenative alkylation is a radical process initiated by DTBP with the assistance of a CAr-Ru bond ortho/para-directing effect.
Li, Gang,Gao, Yuan,Jia, Chunqi,Wang, Shichong,Yan, Bingxu,Fang, Yu,Yang, Suling
supporting information
p. 8758 - 8763
(2020/12/02)

Mechanistic Studies of the Palladium-Catalyzed Desulfinative Cross-Coupling of Aryl Bromides and (Hetero)Aryl Sulfinate Salts
Pyridine and related heterocyclic sulfinates have recently emerged as effective nucleophilic coupling partners in palladium-catalyzed cross-coupling reactions with (hetero)aryl halides. These sulfinate reagents are straightforward to prepare, stable to storage and coupling reaction conditions, and deliver efficient reactions, thus offering many advantages, compared to the corresponding boron-derived reagents. Despite the success of these reactions, there are only scant details of the reaction mechanism. In this study, we use structural and kinetic analysis to investigate the mechanism of these important coupling reactions in detail. We compare a pyridine-2-sulfinate with a carbocyclic sulfinate and establish different catalyst resting states, and turnover limiting steps, for the two classes of reagent. For the carbocyclic sulfinate, the aryl bromide oxidative addition complex is the resting state intermediate, and transmetalation is turnover-limiting. In contrast, for the pyridine sulfinate, a chelated Pd(II) sulfinate complex formed post-transmetalation is the resting-state intermediate, and loss of SO2 from this complex is turnover-limiting. We also investigated the role of the basic additive potassium carbonate, the use of which is crucial for efficient reactions, and deduced a dual function in which carbonate is responsible for the removal of free sulfur dioxide from the reaction medium, and the potassium cation plays a role in accelerating transmetalation. In addition, we show that sulfinate homocoupling is responsible for converting Pd(OAc)2 to a catalytically active Pd(0) complex. Together, these studies shed light on the challenges that must be overcome to deliver improved, lower temperature versions of these synthetically important processes.
Davis, Christopher J.,De Gombert, Antoine,McKay, Alasdair I.,Wheelhouse, Katherine M.,Willis, Michael C.
(2020/02/25)

Potassium trimethylsilanolate enables rapid, homogeneous suzuki-miyaura cross-coupling of boronic esters
Herein, a mild and operationally simple method for the Suzuki-Miyaura cross-coupling of boronic esters is described. Central to this advance is the use of the organic-soluble base, potassium trimethylsilanolate, which allows for a homogeneous, anhydrous cross-coupling. The coupling proceeds at a rapid rate, often furnishing products in quantitative yield in less than 5 min. By applying this method, a >10-fold decrease in reaction time was observed for three published reactions which required >48 h to reach satisfactory conversion.
Delaney, Connor P.,Kassel, Vincent M.,Denmark, Scott E.
p. 73 - 80
(2019/12/24)

A novel and robust heterogeneous Cu catalyst using modified lignosulfonate as support for the synthesis of nitrogen-containing heterocycles
A waste biomass, sodium lignosulfonate, was treated with sodium 2-formylbenzenesulfonate, and the phenylaldehyde condensation product was then used as a robust supporting material to immobilize a copper species. The so-obtained catalyst was characterized by many physicochemical methods including FTIR, EA, FSEM, FTEM, XPS, and TG. This catalyst exhibited excellent catalytic activity in the synthesis of nitrogen-containing heterocycles such as tricyclic indoles bearing 3,4-fused seven-membered rings, 2-arylpyridines, aminonaphthalenes and 3-phenylisoquinolines. In addition, this catalyst showed to be recyclable and could be reused several times without significant loss in activity during the course of the reaction process.
Bai, Rongxian,Gu, Yanlong,Lai, Bingbing,Li, Minghao,Liu, Ping,Ye, Meng
supporting information
p. 2888 - 2902
(2020/12/22)

Photoarylation of Pyridines Using Aryldiazonium Salts and Visible Light: An EDA Approach
A metal-free methodology for the photoarylation of pyridines, in water, is described giving 2 and 4-arylated-pyridines in yields up to 96percent. The scope of the aryldiazonium salts is presented showing important results depending on the nature and position of the substituent group in the diazonium salt, that is, electron-donating or electron-withdrawing in the ortho, meta, or para positions. Further heteroaromatics were also successfully photoarylated. Mechanistic studies and comparison between our methodology and similar metal-catalyzed procedures are presented, suggesting the occurrence of a visible-light EDA complex which generates the aryl radical with no need for an additional photocatalyst.
Bartolomeu, Aloisio De A.,Brocksom, Timothy J.,De Oliveira, Kleber T.,No?l, Timothy,Silva, Rodrigo C.
(2019/08/26)

N-heterocyclic carbene enabled rhodium-catalyzed ortho C(sp2)-H borylation at room temperature
We report a rhodium-catalyzed ortho C(sp2)-H borylation of 2-phenylpyridines using commercially available N-heterocyclic carbenes (NHCs) as ligand and pinacolatodiboron (B2pin2) as borylating reagent. The reaction could take place at room temperature, tolerating a wide range of functionalities and affording ortho borylated products in moderate to excellent yields. The current method is also applicable to gram-scale reaction with reduced catalyst loading.
Zhong, Lei,Zong, Zhi-Hong,Wang, Xi-Cun
supporting information
p. 2547 - 2552
(2019/03/27)

Enabling Catalytic Arene C-H Amidomethylation via Bis(tosylamido)methane as a Sustainable Formaldimine Releaser
Addition of catalytic arene C-H to formaldimines has been enabled by Ru(II)-catalyzed amidomethylation with bis(tosylamido)methane as a catalytic formaldimine releaser. The new process provides an atom-efficient and sustainable solution to address the challenges of formaldimines in this type of transformation. Furthermore, new synthetic routes based on this catalytic system have been developed for step-efficient access to N-heterotricyclic core structures that are pharmaceutically relevant.
Li, Zhong-Yuan,Chaminda Lakmal, Hetti Handi,Cui, Xin
supporting information
p. 3735 - 3740
(2019/05/24)

The ubiquitous cross-coupling catalyst system 'Pd(OAc)2'/2PPh3 forms a unique dinuclear PdI complex: An important entry point into catalytically competent cyclic Pd3 clusters
Palladium(ii) acetate 'Pd(OAc)2'/nPPh3 is a ubiquitous precatalyst system for cross-coupling reactions. It is widely accepted that reduction of in situ generated trans-[Pd(OAc)2(PPh3)2] affords [Pd0(PPh3)n] and/or [Pd0(PPh3)2(OAc)]- species which undergo oxidative addition reactions with organohalides-the first committed step in cross-coupling catalytic cycles. In this paper we report for the first time that reaction of Pd3(OAc)6 with 6 equivalents of PPh3 (i.e. a Pd/PPh3 ratio of 1?:?2) affords a novel dinuclear PdI complex [Pd2(μ-PPh2)(μ2-OAc)(PPh3)2] as the major product, the elusive species resisting characterization until now. While unstable, the dinuclear PdI complex reacts with CH2Cl2, p-fluoroiodobenzene or 2-bromopyridine to afford Pd3 cluster complexes containing bridging halide ligands, i.e. [Pd3(X)(PPh2)2(PPh3)3]X, carrying an overall 4/3 oxidation state (at Pd). Use of 2-bromopyridine was critical in understanding that a putative 14-electron mononuclear 'PdII(R)(X)(PPh3)' is released on forming [Pd3(X)(PPh2)2(PPh3)3]X clusters from [Pd2(μ-PPh2)(μ2-OAc)(PPh3)2]. Altering the Pd/PPh3 ratio to 1?:?4 forms Pd0(PPh3)3 quantitatively. In an exemplar Suzuki-Miyaura cross-coupling reaction, the importance of the 'Pd(OAc)2'/nPPh3 ratio is demonstrated; catalytic efficacy is significantly enhanced when n = 2. Employing 'Pd(OAc)2'/PPh3 in a 1?:?2 ratio leads to the generation of [Pd2(μ-PPh2)(μ2-OAc)(PPh3)2] which upon reaction with organohalides (i.e. substrate) forms a reactive Pd3 cluster species. These higher nuclearity species are the cross-coupling catalyst species, when employing a 'Pd(OAc)2'/PPh3 of 1?:?2, for which there are profound implications for understanding downstream product selectivities and chemo-, regio- and stereoselectivities, particularly when employing PPh3 as the ligand.
Scott, Neil W. J.,Ford, Mark J.,Schotes, Christoph,Parker, Rachel R.,Whitwood, Adrian C.,Fairlamb, Ian J. S.
p. 7898 - 7906
(2019/09/06)

Effects of fluorine substituent on properties of cyclometalated iridium(III) complexes with a 2,2′-bipyridine ancillary ligand
Cationic cyclometalated Ir(III) complexes (Ir1-Ir5) with fluorine-substituted 2-phenylpyridine (ppy) derivatives as C^N cyclometalating ligands and 2,2′-bipyridine (bpy) as the ancillary ligand, have been synthesized and fully characterized. The influences of the number and the position of fluorine atoms at the cyclometalating ligands on the photophysical, electrochemical and oxygen sensing properties of the Ir(III) complexes have been investigated systematically. The introduction of fluorine on the C^N cyclometalating ligands of the complexes results in blue-shifts of the maximum emission wavelengths, and increases in the photoluminescence quantum yields (ΦPL), phosphorescence lifetimes and energy gaps, compared to the non-fluorinated [Ir(ppy)2(bpy)]+PF6? (Ir0). Among them, 2-(2,4-difluorophenyl)pyridine-derived Ir4 shows the maximum blue-shift (514 nm vs. 575 nm for Ir0) and the highest ΦPL (50.8% vs. 6.5% for Ir0). The complex Ir3 with 2-(4-fluorophenyl)-5-fluoropyridine as C^N ligand exhibits the highest oxygen sensitivity and excellent operational stability in 10 cycles within 4000 s.
Chen, Yan,Liu, Chun,Wang, Lei
supporting information

(2019/11/05)

Scope and limitation of propylene carbonate as a sustainable solvent in the Suzuki-Miyaura reaction
The Suzuki-Miyaura reaction is one of the most used transformations in drug research. Thus making this reaction more sustainable is of considerable current interest. Here we show that propylene carbonate (PC) can be used as a solvent for the Suzuki-Miyaura reaction. PC is one of the greenest solvents since it is synthesized under green conditions by the use of carbon dioxide in the air. All reactions proceeded well and good or excellent yields were observed for the biaryl products. Nonetheless in the case of pyridazinones, 2-hydroxypropyl- chain containing side-products were observed. Importantly, this fact allowed the isolation of several novel compounds which were generated under prominently green conditions.
Czompa, Andrea,Pásztor, Balázs László,Sahar, Jennifer Alizadeh,Mucsi, Zoltán,Bogdán, Dóra,Ludányi, Krisztina,Varga, Zoltán,Mándity, István M.
p. 37818 - 37824
(2019/12/03)

Ruthenium-Catalyzed Reductive Cleavage of Unstrained Aryl-Aryl Bonds: Reaction Development and Mechanistic Study
Cleavage of carbon-carbon bonds has been found in some important industrial processes, for example, petroleum cracking, and has inspired development of numerous synthetic methods. However, nonpolar unstrained C(aryl)-C(aryl) bonds remain one of the toughest bonds to be activated. As a detailed study of a fundamental reaction mode, here a full story is described about our development of a Ru-catalyzed reductive cleavage of unstrained C(aryl)-C(aryl) bonds. A wide range of biaryl compounds that contain directing groups (DGs) at 2,2′ positions can serve as effective substrates. Various heterocycles, such as pyridine, quinoline, pyrimidine, and pyrazole, can be employed as DGs. Besides hydrogen gas, other reagents, such as Hantzsch ester, silanes, and alcohols, can be employed as terminal reductants. The reaction is pH neutral and free of oxidants; thus a number of functional groups are tolerated. Notably, a one-pot C-C activation/C-C coupling has been realized. Computational and experimental mechanistic studies indicate that the reaction involves a ruthenium(II) monohydride-mediated C(aryl)-C(aryl) activation and the resting state of the catalyst is a η4-coordinated ruthenium(II) dichloride complex, which could inspire development of other transformations based on this reaction mode.
Zhu, Jun,Chen, Peng-hao,Lu, Gang,Liu, Peng,Dong, Guangbin
supporting information
p. 18630 - 18640
(2019/11/21)

Reversible Concerted Metalation-Deprotonation C-H Bond Activation by [Cp*RhCl2]2
The reversibility of the concerted metalation-deprotonation exchange of eight para-substituted phenylpyridines is examined with the parent Cp*RhCl(κ-C,N-NC5H4-C6H4). Equilibrium constants are determined, and the free energies are used to extract the most important parameters that control the thermodynamics. Keq values are found to correlate best with heterolytic C-H bond strengths but in a way that is not obvious considering the electrophilic nature of these activations.
Vanderweide, Andrew I.,Brennessel, William W.,Jones, William D.
supporting information
p. 12960 - 12965
(2019/10/11)

Suzuki–Miyaura Coupling of (Hetero)Aryl Sulfones: Complementary Reactivity Enables Iterative Polyaryl Synthesis
Ideal organic syntheses involve the rapid construction of C?C bonds, with minimal use of functional group interconversions. The Suzuki–Miyaura cross-coupling (SMC) is a powerful way to form biaryl linkages, but the relatively similar reactivity of electrophilic partners makes iterative syntheses involving more than two sequential coupling events difficult to achieve without additional manipulations. Here we introduce (hetero)aryl sulfones as electrophilic coupling partners for the SMC reaction, which display an intermediate reactivity between those of typical aryl (pseudo)halides and nitroarenes. The new complementary reactivity allows for rapid sequential cross-coupling of arenes bearing chloride, sulfone and nitro leaving groups, affording non-symmetric ter- and quateraryls in only 2 or 3 steps, respectively. The SMC reactivity of (hetero)aryl sulfones is demonstrated in over 30 examples. Mechanistic experiments and DFT calculations are consistent with oxidative addition into the sulfone C?S bond as the turnover-limiting step. The further development of electrophilic cross-coupling partners with complementary reactivity may open new possibilities for divergent iterative synthesis starting from small pools of polyfunctionalized arenes.
Chatelain, Paul,Sau, Abhijit,Rowley, Christopher N.,Moran, Joseph
p. 14959 - 14963
(2019/11/05)

Perylenequinonoid-catalyzed photoredox activation for the direct arylation of (het)arenes with sunlight
Naturally occurring perylenequinonoid pigments (PQPs) have attracted considerable attention owing to their excellent properties of photosensitization. They have been widely investigated as an aspect of photophysics and photobiology. However, their applications in photocatalysis are yet to be explored. We report here that sunlight along with 1 mol% cercosporin, which is one of the perylenequinonoid pigments, catalyzes the direct C-H bond arylation of (het)arenes by a photoredox process with good regioselectivity and broad functional group compatibility. Furthermore, a gram-scale reaction with great conversions of substrates was achieved even by a cercosporin-containing supernatant without organic solvent extraction and purification after liquid fermentation. Thus we set up a bridge between microbial fermentation and organic photocatalysis for chemical reactions in a sustainable, environmentally friendly manner.
Zhang, Shiwei,Tang, Zhaocheng,Bao, Wenhao,Li, Jia,Guo, Baodang,Huang, Shuping,Zhang, Yan,Rao, Yijian
supporting information
p. 4364 - 4369
(2019/05/10)

NITROGEN-CONTAINING BIOPOLYMER-BASED CATALYSTS, THEIR PREPARATION AND USES IN HYDROGENATION PROCESSES, REDUCTIVE DEHALOGENATION AND OXIDATION
The present invention relates to a process for the preparation of a nitrogen containing biopolymer-based catalyst by pyrolysis of a metal complex with a nitrogen-containing biopolymer and to the nitrogen containing biopolymer-based catalysts obtainable by this process. In particular, the invention relates to a nitrogen containing biopolymer-based catalyst comprising metal particles and at least one nitrogen containing carbon layer. The invention also relates to the use of a nitrogen containing biopolymer-based catalyst in a hydrogenation process, preferably in a process for hydrogenation of nitroarenes, nitriles or imines; in a reductive dehalogenation process of C-X bonds, wherein X is CI, Br or I, preferably in a process for dehalogenation of organohalides or in a process for deuterium labelling of arenes via dehalogenation of organohalides; or in an oxidation process. Further, the invention relates to a metal complex with the nitrogen containing biopolymer, wherein the metal is a transition metal selected from the group consisting of manganese, ruthenium, cobalt, rhodium, nickel, palladium and platinum, preferably cobalt or nickel, and wherein the nitrogen containing biopolymer is selected from chitosan, chitin and a polyamino acid, preferably chitosan or chitin.
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(2018/07/29)

An Iron-Based Long-Lived Catalyst for Direct C?H Arylation of Arenes and Heteroarenes
Direct C?H arylation of arenes and heteroarenes to biaryls at ambient temperature has been accomplished using a phenalenyl-supported iron(III) catalyst. The present catalyst requires a chemical reductant such as potassium and functions without any light stimulation. C?H arylation of various heteroarenes including pyridine as well as unactivated arene such as benzene delivered good to excellent yield (28 examples, up to 92 %) at room temperature. A combined effort based on experiments and theoretical calculations established that a phenalenyl-based radical species (generated by chemical reduction of the iron(III) coordinated phenalenyl complex) plays key role during the catalysis. Furthermore, this catalyst displayed remarkable stability during the catalysis, as evident from the fact that it was still usable over ten consecutive catalytic runs without losing its catalytic efficiency.
Chakraborty, Soumi,Ahmed, Jasimuddin,Shaw, Bikash Kumar,Jose, Anex,Mandal, Swadhin K.
p. 17651 - 17655
(2018/11/10)

Suzuki-Miyaura cross-coupling for efficient synthesis of aryl-substituted N-heteroarenes catalyzed by recyclable N-phenylpiperazine-Palladium(II) complex
Polystyrene supported N-phenylpiperazine-Pd(II) complex D was synthesized and characterized by various techniques, including Fourier transform infrared spectroscopy (FTIR), scanning electronmicroscopy (SEM), energy dispersive X-ray spectroscopy (EDX) and thermal analysis (TG-DTA). This heterogeneous Pd(II) complex showed high catalytic efficiency for the Suzuki-Miyaura coupling of arylboronic acids with aryl bromides, aryl chlorides to give the corresponding 2-arylpyridines and heteroarenes. The coupled products were formed in excellent yields at low catalyst loadings under mild reaction conditions. Further, this heterogeneous catalyst showed excellent recyclability and reused for four cycles with no significant decrease in its activity.
Perumgani, Pullaiah C.,Kodicherla, Balaswamy,Mandapati, Mohan Rao,Parvathaneni, Sai Prathima
p. 227 - 232
(2018/04/02)

C6-Selective Direct Arylation of 2-Phenylpyridine via an Activated N-methylpyridinium Salt: A Combined Experimental and Theoretical Study
An elegant pre-activation strategy, based on the formation of N-methylpyridinium iodide salts for C6-selective direct arylation of 2-phenylpyridines using Pd/Cu cooperative catalysis, has been developed. By this methodology, a wide range of unsymmetrical 2, 6-diarylpyridines were synthesized with high reactivity and regioselectivity as well as good functional group tolerance. In particular, challenging substrates bearing electron donating groups (EDGs), such as OMe, NMe2, were also successfully employed in this reaction. Deuterium incorporation studies revealed that the C?H bond acidity is improved significantly in N-methylpyridinium salts compared with their N-Oxide and N-iminopyridinium ylide counterparts, thus solving the long-standing problem associated with previous strategies for the synthesis of diaryl pyridines. Finally, the control experiments and DFT calculations supported a Pd-catalyzed and Cu-mediated mechanism in which a carbenoid copper species that is formed in-situ from N-methylpyridinium salts, participates in a Pd-catalyzed arylation followed by an iodide-promoted N-demethylation process. (Figure presented.).
Yin, Changzhen,Zhong, Kangbao,Li, Wenjing,Yang, Xiao,Sun, Rui,Zhang, Chunchun,Zheng, Xueli,Yuan, Maolin,Li, Ruixiang,Lan, Yu,Fu, Haiyan,Chen, Hua
supporting information
p. 3990 - 3998
(2018/09/12)

A tetranuclear CuII2DyIII2 coordination cluster as a Suzuki (C-C) coupling reaction promoter
The air-stable tetranuclear coordination cluster [CuII2DyIII2L4(NO3)2(CH3CN)2]·2(CH3CN), which can be obtained in high yield, promotes the Suzuki coupling reaction of phenylboronic acid with substituted aryl halides under environmentally benign conditions.
Kumar, Prashant,Griffiths, Kieran,Anson, Christopher E.,Powell, Annie K.,Kostakis, George E.
supporting information
p. 17202 - 17205
(2019/01/03)

Metallaphotoredox-Mediated Csp2-H Hydroxylation of Arenes under Aerobic Conditions
The direct hydroxylation of 2-arylpyridines and 2-arylbenzothiazoles via the merger of organic photoredox and metal catalysis is reported where 4CzIPN is used as the visible-light photocatalyst and Pd(OAc)2 as the metal catalyst. This method has been employed to synthesize organic molecules exhibiting excited-state intramolecular proton transfer properties for generating tunable luminescence responses.
Shah, Sk. Sheriff,Paul, Amrita,Bera, Manoranjan,Venkatesh, Yarra,Singh, N. D. Pradeep
supporting information
p. 5533 - 5536
(2018/09/21)

[2,2′-bipyridin]-6(1 H)-one, a Truly Cooperating Ligand in the Palladium-Mediated C-H Activation Step: Experimental Evidence in the Direct C-3 Arylation of Pyridine
The ligand [2,2′-bipyridin]-6(1H)-one (bipy-6-OH) has a strong accelerating effect on the Pd-catalyzed direct arylation of pyridine or arenes. The isolation of relevant intermediates and the study of their decomposition unequivocally show that the deprotonated coordinated ligand acts as a base and assists the cleavage of the C-H bond. Mechanistic work indicates that the direct arylation of pyridine with this ligand occurs through a Pd(0)/Pd(II) cycle. Because of this dual ligand-intramolecular base role, there is no need for an available coordination site on the metal for an external base, a difficulty encountered when chelating ligands are used in coupling reactions that involve a C-H cleavage step.
Salamanca, Vanesa,Toledo, Alberto,Albéniz, Ana C.
supporting information
p. 17851 - 17856
(2019/01/04)

Transition-Metal-Free Decarboxylative Arylation of 2-Picolinic Acids with Arenes under Air Conditions
A facile, transition-metal-free, and direct decarboxylative arylation of 2-picolinic acids with simple arenes is described. The oxidative decarboxylative arylation of 2-picolinic acids with arenes proceeds readily via N-chloro carbene intermediates to afford 2-arylpyridines in satisfactory to good yields under transition-metal-free conditions. This new type of decarboxylative arylation is operationally simple and scalable and exhibits high functional-group tolerance. Various synthetically useful functional groups, such as halogen atoms, methoxycarbonyl, and nitro, remain intact during the decarboxylative arylation of 2-picolinic acids.
Zhang, Xitao,Feng, Xiujuan,Zhou, Chuancheng,Yu, Xiaoqiang,Yamamoto, Yoshinori,Bao, Ming
supporting information
p. 7095 - 7099
(2018/11/23)

Synthesis of Bi(hetero)aryls via Sequential Oxidation and Decarboxylation of Benzylamines in a Batch/Fully Automated Continuous Flow Process
Catalytic dehydrogenative cross-coupling of two C–H bonds represents a green strategy in view of the atom- and step-economy. However, the challenge is to discover a new innovative bond strategy, especially for the direct coupling between Csp2–H
Mahajan, Bhushan,Aand, Dnyaneshwar,Singh, Ajay K.
supporting information
p. 2831 - 2835
(2018/06/21)

Accessing Heterobiaryls through Transition-Metal-Free C-H Functionalization
Herein we report a transition-metal-free synthetic protocol for heterobiaryls, one of the most important pharmacophores in the modern drug industry, employing a new multidonor phenalenyl (PLY)-based ligand. The current procedure offers a wide substrate scope (24 examples) with a low catalyst loading resulting in an excellent product yield (up to 95%). The reaction mechanism involves a single electron transfer (SET) from a phenalenyl-based radical to generate a reactive heteroaryl radical. To establish the mechanism, we have isolated the catalytically active SET initiator, characterizing by a magnetic study.
Banik, Ananya,Paira, Rupankar,Shaw, Bikash Kumar,Vijaykumar, Gonela,Mandal, Swadhin K.
p. 3236 - 3244
(2018/03/23)

Palladium-catalysed electrophilic aromatic C-H fluorination
Aryl fluorides are widely used in the pharmaceutical and agrochemical industries, and recent advances have enabled their synthesis through the conversion of various functional groups. However, there is a lack of general methods for direct aromatic carbon-hydrogen (C-H) fluorination. Conventional methods require the use of either strong fluorinating reagents, which are often unselective and difficult to handle, such as elemental fluorine, or less reactive reagents that attack only the most activated arenes, which reduces the substrate scope. A method for the direct fluorination of aromatic C-H bonds could facilitate access to fluorinated derivatives of functional molecules that would otherwise be difficult to produce. For example, drug candidates with improved properties, such as increased metabolic stability or better blood-brain-barrier penetration, may become available. Here we describe an approach to catalysis and the resulting development of an undirected, palladium-catalysed method for aromatic C-H fluorination using mild electrophilic fluorinating reagents. The reaction involves a mode of catalysis that is unusual in aromatic C-H functionalization because no organometallic intermediate is formed; instead, a reactive transition-metal-fluoride electrophile is generated catalytically for the fluorination of arenes that do not otherwise react with mild fluorinating reagents. The scope and functional-group tolerance of this reaction could provide access to functional fluorinated molecules in pharmaceutical and agrochemical development that would otherwise not be readily accessible.
Yamamoto, Kumiko,Li, Jiakun,Garber, Jeffrey A. O.,Rolfes, Julian D.,Boursalian, Gregory B.,Borghs, Jannik C.,Genicot, Christophe,Jacq, Jér?me,Van Gastel, Maurice,Neese, Frank,Ritter, Tobias
p. 511 - 514
(2018/03/02)

An active catalytic system for Suzuki-Miyaura cross-coupling reactions using low levels of palladium loading
An easily available Pd(OAc)2/(2-(anthracen-9-yl)-1H-inden-3-yl) dicyclohexylphosphine/toluene/iPrOH/water catalytic system was developed, which shows high catalytic activity in the Suzuki-Miyaura cross-coupling reactions of a diverse array of aryl and heteroaryl chlorides with Pd loadings down to 0.01 mol%.
Yan, Meng-Qi,Yuan, Jia,Lan, Fang,Zeng, Si-Hao,Gao, Meng-Yue,Liu, Sheng-Hua,Chen, Jian,Yu, Guang-Ao
supporting information
p. 3924 - 3929
(2017/07/10)

α-Halo carbonyls enable: Meta selective primary, secondary and tertiary C-H alkylations by ruthenium catalysis
A catalytic meta selective C-H alkylation of arenes is described using a wide range of α-halo carbonyls as coupling partners. Previously unreported primary alkylations with high meta selectivity have been enabled by this methodology whereas using straight chain alkyl halides affords ortho substituted products. Mechanistic analysis reveals an activation pathway whereby cyclometalation with a ruthenium(ii) complex activates the substrate molecule and is responsible for the meta selectivity observed. A distinct second activation of the coupling partner allows site selective reaction between both components.
Paterson, Andrew J.,Heron, Callum J.,McMullin, Claire L.,Mahon, Mary F.,Press, Neil J.,Frost, Christopher G.
supporting information
p. 5993 - 6000
(2017/07/25)

Derisking the Cu-Mediated 18F-Fluorination of Heterocyclic Positron Emission Tomography Radioligands
Molecules labeled with fluorine-18 (18F) are used in positron emission tomography to visualize, characterize and measure biological processes in the body. Despite recent advances in the incorporation of 18F onto arenes, the development of general and efficient approaches to label radioligands necessary for drug discovery programs remains a significant task. This full account describes a derisking approach toward the radiosynthesis of heterocyclic positron emission tomography (PET) radioligands using the copper-mediated 18F-fluorination of aryl boron reagents with 18F-fluoride as a model reaction. This approach is based on a study examining how the presence of heterocycles commonly used in drug development affects the efficiency of 18F-fluorination for a representative aryl boron reagent, and on the labeling of more than 50 (hetero)aryl boronic esters. This set of data allows for the application of this derisking strategy to the successful radiosynthesis of seven structurally complex pharmaceutically relevant heterocycle-containing molecules.
Taylor, Nicholas J.,Emer, Enrico,Preshlock, Sean,Schedler, Michael,Tredwell, Matthew,Verhoog, Stefan,Mercier, Joel,Genicot, Christophe,Gouverneur, Véronique
supporting information
p. 8267 - 8276
(2017/06/27)

Ru-Catalyzed Regioselective Direct Hydroxymethylation of (Hetero)Arenes via C-H Activation
An efficient and direct ruthenium-catalyzed regioselective hydroxymethylation of (hetero)arenes via C-H activation with paraformaldehyde as a hydroxymethylating reagent is described. The corresponding products can be obtained in good to excellent yield. A number of aryl aldehydes can also be used in place of paraformaldehyde giving the desired alcohol products with similarly good results.
Zhang, Guo-Fu,Li, Yue,Xie, Xiao-Qiang,Ding, Cheng-Rong
supporting information
p. 1216 - 1219
(2017/03/14)

Ruthenium-Catalyzed meta-Selective C?H Mono- and Difluoromethylation of Arenes through ortho-Metalation Strategy
The first example for the ruthenium-catalyzed ligand-directed meta-selective C?H mono- and difluoromethylation is developed, affording a variety of new meta-mono- and difluoromethylated 2-phenylpyridines, 2-phenylpyrimidines, and 1-phenylpyrazoles in moderate-to-good yields. This new transformation exhibits broad substrate scope, good functional group tolerance, and high efficiency, and offers a practical approach to synthesize mono- and difluoromethylated arenes. Mechanistic studies indicate that a reaction pathway involving palladium-initiated radical species is involved in the catalytic cycle. The new dual catalytic system consisting of compatible ruthenium(II) and palladium(0) complexes enables the key processes of C?H activation and mono-/difluoromethyl-radical formation to occur and achieves the meta-selective functionalization efficiently. In addition, the present protocol can also be extended to non-fluoromethylation.
Li, Zhong-Yuan,Li, Liang,Li, Qi-Li,Jing, Kun,Xu, Hui,Wang, Guan-Wu
supporting information
p. 3285 - 3290
(2017/03/16)

Copper-mediated C-H cyanation of (hetero)arenes with ethyl (ethoxymethylene)cyanoacetate as a cyanating agent
A copper-mediated direct C-H cyanation of (hetero)arenes with ethyl (ethoxymethylene)cyanoacetate as a safe cyanating agent has been successfully developed by using molecular oxygen as the oxidant. The reaction tolerates a variety of functional groups and provides a facile and efficient method for the synthesis of a wide range of (hetero)aryl nitriles.
Qi, Chaorong,Hu, Xiaohan,Jiang, Huanfeng
p. 7994 - 7997
(2017/07/22)

Palladium-catalyzed decarboxylative, decarbonylative and dehydrogenative C(sp2)-H acylation at room temperature
Over the past few decades, an impressive array of C-H activation methodology has been developed for organic synthesis. However, due to the inherent inertness of the C-H bonds (e.g. ～110 kcal mol-1 for the cleavage of C(aryl)-H bonds) harsh reaction conditions have been realized to overcome high energetic transition states resulting in a limited substrate scope and functional group tolerance. Therefore, the development of mild C-H functionalization protocols is in high demand to exploit the full potential of the C-H activation strategy in the synthesis of a complex molecular framework. Although, electron-rich substrates undergo electrophilic metalation under relatively mild conditions, electron-deficient substrates proceed through a rate-limiting C-H insertion under forcing conditions at high temperature. In addition, a stoichiometric amount of toxic silver salt is frequently used in palladium catalysis to facilitate the C-H activation process which is not acceptable from the environmental and industrial standpoint. We report herein, a Pd(ii)-catalyzed decarboxylative C-H acylation of 2-arylpyridines with α-ketocarboxylic acids under mild conditions. The present protocol does not require stoichiometric silver(i) salts as additives and proceeds smoothly at ambient temperature. A novel decarbonylative C-H acylation reaction has also been accomplished using aryl glyoxals as acyl surrogates. Finally, a practical C-H acylation via a dehydrogenative pathway has been demonstrated using commercially available benzaldehydes and aqueous hydroperoxides. We also disclose that acetonitrile solvent is optimal for the acylation reaction at room temperature and has a prominent role in the reaction outcome. Control experiments suggest that the acylation reaction via decarboxylative, decarbonylative and dehydrogenative proceeds through a radical pathway. Thus we disclose a practical protocol for the sp2 C-H acylation reaction.
Hossian, Asik,Manna, Manash Kumar,Manna, Kartic,Jana, Ranjan
supporting information
p. 6592 - 6603
(2017/08/16)

ONE STEP DIRECT ARYLATION OF COMMODITY CHEMICALS TO SPECIALTY CHEMICALS BY TANDEM CATALYTIC PLATFORM
The present invention relates to a continuous direct arylation process based on a tandem catalyst for synthesizing specialty chemicals. A method for synthesizing an aryl-aryl structure from a substrate selected from the group consisting of benzyl alcohol, benzyl amine and toluene which are low value added compounds is developed using a silver ion-containing tandem catalyst. The method is applied for synthesizing hexaphenyl arylene and can be applied for synthesizing high value added compounds (not only natural substances and chemical compounds but pharmaceutical and agricultural pesticide relative fields) directly from primary raw materials through the reaction.COPYRIGHT KIPO 2017
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Paragraph 0044-0048; 0106

(2018/02/28)

Fluorine-containing aromatic derivatives of selective hydrogenation reduction method
The invention discloses a selective hydrogenation reduction method of a fluorine-containing aromatic hydrocarbon derivative, and particularly discloses a preparation method of a compound shown in a general formula C1, C2 or C3. The preparation method comprises the following step of: reacting a compound shown in a general formula A1, A2 or A3 with a compound shown in a general formula B in the presence of a catalyst, thus forming the compound shown in the general formula C1, C2 or C3.
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(2017/11/27)

Nickel-Catalyzed Cross-Coupling Reaction of Aryl Sulfoxides with Arylzinc Reagents: When the Leaving Group is an Oxidant
Nickel-catalyzed Negishi-type cross-coupling of aryl methyl sulfoxides with arylzinc reagents has been developed. By consuming the catalyst-oxidizing methanesulfenate anion through oxidative homocoupling of the arylzinc reagent, smooth catalyst turnover c
Yamamoto, Keita,Otsuka, Shinya,Nogi, Keisuke,Yorimitsu, Hideki
p. 7623 - 7628
(2017/11/14)

A new face of phenalenyl-based radicals in the transition metal-free C-H arylation of heteroarenes at room temperature: Trapping the radical initiator: Via C-C σ-bond formation
The radical-mediated transition metal-free approach for the direct C-H bond functionalization of arenes is considered as a cost effective alternative to transition metal-based catalysis. An organic ligand-based radical plays a key role by generating an aryl radical which undergoes a subsequent functionalization process. The design principle of the present study takes advantage of a relatively stable odd alternant hydrocarbon-based phenalenyl (PLY) radical. In this study, the first transition metal-free catalyzed direct C-H arylation of a variety of heteroarenes such as azoles, furan, thiophene and pyridine at room temperature has been reported using a phenalenyl-based radical without employing any photoactivation step. This protocol has been successfully applied to the gram scale synthesis of core moieties of bioactive molecules. The phenalenyl-based radical initiator has been characterized crystallographically by trapping it via the formation of a C-C σ-bond between the phenalenyl radical and solvent-based radical species.
Ahmed, Jasimuddin,Sreejyothi,Vijaykumar, Gonela,Jose, Anex,Raj, Manthan,Mandal, Swadhin K.
p. 7798 - 7806
(2017/10/30)

Preparation method for biaryl compound
The invention provides a preparation method for a biaryl compound. The preparation method comprises the step of performing cross coupling reaction on a substrate A and an organic zinc reagent B under a catalytic effect of a catalyst, thereby acquiring the biaryl compound, wherein a chemical structure of the substrate A is shown in the description; the organic zinc reagent B has the chemical structure shown in the description; and the catalyst is one or more of nickel salt, copper salt and cobalt salt. Compared with the other noble metal catalysts, such as, metal palladium catalyst, the catalyst adopting nickel salt, copper salt or cobalt salt is low in cost, so that the reaction cost of the biaryl compound is greatly reduced. Meanwhile, the aryl sulphonate or aryl halide shown as the substrate A has an excellent electrophilic property, is an electrophilic reagent with an excellent property and has the advantages of easiness in preparation, low cost, high activity and high stability. The substrate A and the organic zinc reagent B have cross coupling reaction under the effect of nickel salt, copper salt or cobalt salt so as to generate the biaryl compound and the reaction yield is higher.
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Paragraph 0067-0069

(2017/07/20)

DIRECT PALLADIUM-CATALYZED AROMATIC FLUORINATION
Provided herein are palladium complexes comprising a ligand of Formula (Α') and a ligand of Formula (B), wherein R1-R18 are as defined herein. The palladium complexes are useful in methods of fluorinating aryl and heteroaryl substrates. Further provided are compositions and kits comprising the palladium complexes.
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Paragraph 00212; 00213

(2017/09/27)

A Biomass-Derived Non-Noble Cobalt Catalyst for Selective Hydrodehalogenation of Alkyl and (Hetero)Aryl Halides
Hydrodehalogenation is a straightforward approach for detoxifications of harmful anthropogenic organohalide-based pollutants, as well as removal of halide protecting groups used in multistep syntheses. A novel sustainable catalytic material was prepared from biowaste (chitosan) in combination with an earth-abundant cobalt salt. The heterogeneous catalyst was fully characterized by transmission electron microscope, X-ray diffraction, and X-ray photoelectron spectroscopy measurements, and successfully applied to hydrodehalogenation of alkyl and (hetero)aryl halides with broad scope (>40 examples) and excellent chemoselectivity using molecular hydrogen as a reductant. The general usefulness of this method is demonstrated by successful detoxification of non-degradable pesticides and fire retardants. Moreover, the potential of the catalyst as a deprotection tool is demonstrated in a multistep synthesis of (±)-peronatin B (alkaloid).
Sahoo, Basudev,Surkus, Annette-Enrica,Pohl, Marga-Martina,Radnik, J?rg,Schneider, Matthias,Bachmann, Stephan,Scalone, Michelangelo,Junge, Kathrin,Beller, Matthias
supporting information
p. 11242 - 11247
(2017/09/02)

Synthesis of 3-Substituted 2-Arylpyridines via Cu/Pd-Catalyzed Decarboxylative Cross-Coupling of Picolinic Acids with (Hetero)Aryl Halides
A decarboxylative cross-coupling of 3-substituted picolinic acids with (hetero)aryl halides is presented. In the presence of catalytic Cu2O and Pd(1,5-cyclooctadiene)Cl2 with 2-dicyclohexylphosphino-2′-(N,N-dimethylamino)biphenyl as the ligand, both electron-rich and electron-deficient aryl bromides and chlorides as well as heteroaryl bromides were successfully coupled with various picolinate salts under mild conditions in yields up to 96%. This protocol provides an efficient entry to 2-(hetero)arylpyridines, an attractive substance class in drug discovery.
Hackenberger, Dagmar,Weber, Philip,Blakemore, David C.,Goossen, Lukas J.
p. 3917 - 3925
(2017/04/11)

Interface coassembly of mesoporous MoS2 based-frameworks for enhanced near-infrared light driven photocatalysis
The three-dimensional porous Fe3O4@Cu2-xS-MoS2 framework is reported for the first time. The as-prepared 3D framework exhibits good structural stability, high surface area, enhanced adsorption capacity to substrates, and strong absorption in the NIR range. As a result, such hybrid frameworks exhibit excellent NIR-light photocatalytic activity and stable cycling for the direct arylation of heteroaromatics at room temperature.
Zhi, Lihua,Zhang, Haoli,Yang, Zhengyin,Liu, Weisheng,Wang, Baodui
supporting information
p. 6431 - 6434
(2016/05/24)

Microwave-Assisted Synthesis of Heteroleptic Ir(III)+ Polypyridyl Complexes
We report a rapid, one-pot, operationally simple, and scalable preparation of valuable cationic heteroleptic iridium(III) polypyridyl photosensitizers. This method takes advantage of two consecutive microwave irradiation steps in the same reactor vial, avoiding the need for additional reaction purifications. A number of known heteroleptic iridium(III) complexes are prepared in up to 96% yield. Notably, this method is demonstrated to provide the synthetically versatile photosensitizer [Ir(ppy)2(dtbbpy)]PF6 in >1 g quantities in less than 5 h of bench time. We envision this method will help accelerate future developments in visible-light-dependent chemistry.
Monos, Timothy M.,Sun, Alexandra C.,McAtee, Rory C.,Devery, James J.,Stephenson, Corey R. J.
p. 6988 - 6994
(2016/08/30)

POPd/TBAB co-catalyzed Suzuki cross-coupling reaction of heteroaryl chlorides/bromides with 4-fluorophenylboronic acid in water
An organic solvent free and efficient heterogeneous synthesis for bridging heteroaryl halides and 4-fluorophenylboronic acid was studied in aqueous media according to the Suzuki cross-coupling protocol. High yields of heteroaryl-aryl fluorides were successfully obtained with: chloro-/bromo-substituted pyridine, thiophene, indole, and inzole in neat water using palladium phosphinous acid complexes (POPd)/tetrabutylammonium bromide (TBAB) as co-catalysts. A possible mechanism for the heterogeneous coupling reaction is proposed and discussed according to the function of the TBAB interphases. The notable properties of the reported method are highly co-catalytic activity, hetero-atom tolerance, simple separating procedure and little environmental disposal impact.
Li, Ben,Zhang, Zhiqiang
p. 637 - 644
(2016/02/19)

Palladium catalyzed ortho-C-H-acylation of 2-arylpyridines using phenylacetylenes and styrene epoxide
A palladium-catalyzed ortho-C-H-acylation of 2-arylpyridine using phenylacetylenes and styrene epoxide as the acylated reagents was developed. With the employment of tert-butyl hydroperoxide (TBHP) as the oxidant and a phosphorous ligand, the protocol generates corresponding aryl ketones in moderated to good yields with high regioselectivity and good functional group compatibility.
Zhang, Qian,Wang, Yang,Yang, Tingting,Li, Li,Li, Dong
supporting information
p. 90 - 94
(2015/12/23)