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Novel iota carrageenan-based RhCl3 as an efficient and recyclable catalyst in Suzuki cross coupling
RhCl3 was heterogenized into renewable polysaccharide supports, and the effect of polysaccharide type on the new catalyst performances in a Suzuki cross-coupling reaction was studied. The conversion of the fresh iota carrageenan heterogeneous system (?-RhCl3), was found to be the highest, whereas it was lower than the conversion of its homogeneous analogue. In addition, the ?-RhCl3 (catalyst loading of 6.5 % wt) was proven to be efficient heterogeneous catalyst that was easily recycled, whereas the conversion was increased in the first and second cycles. Scanning electronic microscopy (SEM) combining Energy dispersive X-ray spectrometry and Surface analysis by X-ray photoelectron spectroscopy were performed, confirming that RhCl3 was embedded within the ?-carrageenan. The Fourier-transform infrared spectrometry of the heterogeneous ?-RhCl3 catalyst was compared to that of the native polysaccharide, and no new bands were detected. Nonetheless, a comparison of SEM image of ?-carrageenan with and without RhCl3, as well as rheological measurements of the aqueous solution of ? with and without RhCl3, indicated the incorporation of the polysaccharide with the RhCl3.
Leviev, Sivan,Levy-Ontman, Oshrat,Wolfson, Adi
(2020)
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Biosynthesis of poly(ethylene glycol)-supported palladium nanoparticles using Colocasia esculenta leaf extract and their catalytic activity for Suzuki-Miyaura cross-coupling reactions
A simple and green protocol for the synthesis of poly(ethylene glycol) stabilized palladium nanoparticles under ambient conditions from the aqueous extracts of Colocasia esculenta leaves has been reported. The nanoparticles are characterized using UV-visible spectroscopy, FTIR spectroscopy, XRD and SEM analysis. The prepared Pd NPs showed excellent catalytic activity towards Suzuki-Miyaura cross coupling reactions for a wide variety of aryl halides and phenyl boronic acid substrates. The catalytic system was found to be recyclable and could be reused in subsequent catalytic runs without significant loss of activity.
Borah, Raju Kumar,Saikia, Hirak Jyoti,Mahanta, Abhijit,Das, Vijay Kumar,Bora, Utpal,Thakur, Ashim Jyoti
p. 72453 - 72457
(2015)
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Pd nanoparticles in hollow magnetic mesoporous spheres: High activity, and magnetic recyclability
The nanoreactor of hollow magnetic mesoporous silica spheres (Pd/HMMS), with Pd and Fe3O4 nanoparticles embedded in the mesoporous silica shell, were successfully prepared by using the colloidal carbon spheres of glucose, Pd and Fe3O4 heteroaggregates as the hard template together with a coating of tetraethoxysilane (TEOS) and cetyltrimethylammonium bromide (CTAB) mixture. The synthesized Pd/HMMS shows excellent catalytic activity in the Suzuki cross-coupling reaction of iodobenzene with phenylboronic acid with over 99% yield in 3 min and can be recycled multiple times without any significant loss in catalytic activity.
Sun, Jian,Dong, Zhengping,Sun, Xun,Li, Ping,Zhang, Fengwei,Hu, Wuquan,Yang, Haidong,Wang, Haibo,Li, Rong
p. 46 - 51
(2013)
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Pd-Cu alloy nanoparticle supported on amine-terminated ionic liquid functional 3D graphene and its application on Suzuki cross-coupling reaction
Well distributed Pd-Cu bimetallic alloy nanoparticles supported on amine-terminated ionic liquid functional three-dimensional graphene (3D IL-rGO/Pd-Cu) as an efficient catalyst for Suzuki cross-coupling reaction has been prepared via a facile synthetic method. The introduction of IL-NH2 cations on the surface of graphene sheets can effectively avoid the re-deposition of graphene sheets, allowing the catalyst to be reused up to 10?cycles. The addition of Cu not only saves cost but also ensures high catalytic efficiency. It is worthy to note that the catalyst 3D IL-rGO/Pd2.5Cu2.5 can efficiently catalyze the Suzuki cross-coupling reaction with the yield up to 100% in 0.25?h, almost one-fold higher than that by the pristine IL-rGO/Pd2.5 catalyst (52%). The Powder X-Ray Diffraction (XRD), combining energy dispersive X-ray spectroscopy (EDS) mapping results confirm the existence and distribution of Pd and Cu in the bimetallic nanoparticles. The transmission electron microscopy (TEM) reveals the nanoparticle size with an average diameter of 3.0?±?0.5?nm. X-ray photoelectron spectroscopy (XPS) analysis proved the presence of electron transfer from Cu to Pd upon alloying. Such alloying-induced electronic modification of Pd-Cu alloy and 3D ionic liquid functional graphene with large specific surface area both accounted for the catalytic enhancement.
Ru, Yu,Huang, Yanli,Wang, Yuanyuan,Dai, Liyi
(2019)
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A selective luminescent probe for the direct time-gated detection of adenosine triphosphate
A molecular probe for the luminescent detection of adenosine nucleotides is presented. The probe, Tb-DOTAm-Phen, readily distinguishes among the three adenosine nucleotides in buffered aqueous conditions at neutral pH, a requirement for the direct monitoring of enzymatic reactions converting adenosine triphosphate (ATP) to adenosine diphosphate or adenosine monophosphate. The probe is most efficient under millimolar concentrations of ATP which are relevant to intracellular conditions. Moreover, the long luminescence lifetime of the probe readily enables time-gating experiments.
Weitz, Evan A.,Chang, Jennifer Y.,Rosenfield, Adam H.,Pierre, Valerie C.
p. 16099 - 16102,4
(2012)
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A Convenient and Stable Heterogeneous Nickel Catalyst for Hydrodehalogenation of Aryl Halides Using Molecular Hydrogen
Hydrodehalogenation is an effective strategy for transforming persistent and potentially toxic organohalides into their more benign congeners. Common methods utilize Pd/C or Raney-nickel as catalysts, which are either expensive or have safety concerns. In this study, a nickel-based catalyst supported on titania (Ni-phen@TiO2-800) is used as a safe alternative to pyrophoric Raney-nickel. The catalyst is prepared in a straightforward fashion by deposition of nickel(II)/1,10-phenanthroline on titania, followed by pyrolysis. The catalytic material, which was characterized by SEM, TEM, XRD, and XPS, consists of nickel nanoparticles covered with N-doped carbon layers. By using design of experiments (DoE), this nanostructured catalyst is found to be proficient for the facile and selective hydrodehalogenation of a diverse range of substrates bearing C?I, C?Br, or C?Cl bonds (>30 examples). The practicality of this catalyst system is demonstrated by the dehalogenation of environmentally hazardous and polyhalogenated substrates atrazine, tetrabromobisphenol A, tetrachlorobenzene, and a polybrominated diphenyl ether (PBDE).
Leonard, David K.,Ryabchuk, Pavel,Anwar, Muhammad,Dastgir, Sarim,Junge, Kathrin,Beller, Matthias
(2022/02/03)

Pd-Catalysed Suzuki-Miyaura cross-coupling of aryl chlorides at low catalyst loadings in water for the synthesis of industrially important fungicides
The Suzuki-Miyaura coupling reaction of electron-poor aryl chlorides in the synthesis of crop protection-relevant active ingredients in water is disclosed. Optimisation of the reaction conditions allowed running the reaction with 50 ppm of Pd-catalyst loading without an additional organic solvent in the cross-coupling reaction step in short reaction times. The system was optimised for the initial cross-coupling step of the large scale produced fungicides Boscalid, Fluxapyroxad and Bixafen up to 97% yield. It is also shown that the Suzuki-Miyaura reaction can be easily scaled up to 50 g using a simple product separation and purification using environmentally benign solvents in the work-up. To show the usability of this method, it was additionally applied in the three-step synthesis of the desired active ingredients.
Goetz, Roland,Hashmi, A. Stephen K.,Orecchia, Patrizio,Petkova, Desislava Slavcheva,Rominger, Frank,Schaub, Thomas
supporting information
p. 8169 - 8180
(2021/11/01)

Preparation method of 2-aminobiphenyl derivative and 2-hydroxybiphenyl derivative
The invention relates to a preparation method for synthesizing a 2-aminobiphenyl derivative and a 2-hydroxybiphenyl derivative, wherein the preparation method comprises the steps: adding a 2-halogenated aniline derivative or a 2-halogenated phenol derivative and a substituted arylboronic acid derivative into an organic solvent at a certain temperature, reacting under the action of a catalyst polyaryl substituted m-phenylenediamine and alkali, and finally obtaining the product 2-aminobiphenyl derivative or 2-hydroxybiphenyl derivative. According to the method, the 2-aminobiphenyl derivative and the 2-hydroxybiphenyl derivative are prepared through the organic secondary amine catalytic reaction, the preparation method is safer and more convenient, the production cost is low, the total yield is high, the catalyst can be recycled, few three wastes are generated, and industrialization is facilitated.
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Paragraph 0024-0027; 0034-0037

(2021/06/12)

Pd/Cu-Free Cobalt-Catalyzed Suzuki and Heck Using Green Bio-Magnetic Hybrid and DFT-Based Theoretical Study
Abstract: Several highly efficient and magnetically recyclable cobalt catalytic systems were prepared using magnetic chitosan and some safe and available organic compounds (Co-ligand@MNPs/Ch). The structure of these nanocomposites was confirmed by various physicochemical techniques such as FT-IR, XRD, TGA, VSM, TEM, SEM, CHNS and ICP-OES. These nano composites exhibit remarkable catalytic efficiency for Suzuki and Heck cross-coupling reactions in mild and green reaction conditions. The facile accessibility of starting materials, possible performance in air and eco-friendly conditions are merits of our catalysts. In addition, to describe and go insight to role and effect of ligands present in these catalysts, electrostatic interactions, density functional theory (DFT) model in molecular method were employed. Graphic Abstract: [Figure not available: see fulltext.]
Hajipour, Abdol R.,Khorsandi, Zahra,Ahmadi, Mehnoosh,Jouypazadeh, Hamidreza,Mohammadi, Bahareh,Farrokhpour, Hossein
p. 2842 - 2850
(2021/02/01)

Catalyst-free synthesis of phenanthridinesviaelectrochemical coupling of 2-isocyanobiphenyls and amines
Catalyst free synthesis of 6-aryl phenanthridines and amides through an electrochemical reaction is reported in this study. The coupling reaction proceeds by the cathodic reduction ofin situformed diazonium ions, which are formed from anilines and an alkyl nitrite. The generated aryl radical diazonium ions coupled from isocyanides furnished the desired products in good yields. This cascade reaction was conducted in an undivided cell equipped with an RVC as the anode and Pt as the cathode usingnBu4NBF4as the electrolyte at room temperature. A series of detailed mechanistic studies have also been performed, including a radical clock experiment and cyclic voltammetry analysis.
Malviya, Bhanwar Kumar,Singh, Karandeep,Jaiswal, Pradeep K.,Karnatak, Manvika,Verma, Ved Prakash,Badsara, Satpal Singh,Sharma, Siddharth
p. 6367 - 6378
(2021/04/16)

Amine-Tagged Fragmented Ligand Installation for Covalent Modification of MOF-74
MOF-74 is one of the most explored metal–organic frameworks (MOFs), but its functionalization is limited to the dative post-synthetic modification (PSM) of the monodentate solvent site. Owing to the nature of the organic ligand and framework structure of MOF-74, the covalent PSM of MOF-74 is very demanding. Herein, we report, for the first time, the covalent PSM of amine-tagged defective Ni-MOF-74, which is prepared by de novo solvothermal synthesis by using aminosalicylic acid as a functionalized fragmented organic ligand. The covalent PSM of the amino group generates metal binding sites, and subsequent post-synthetic metalation with PdII ions affords the PdII-incorporated Ni-MOF-74 catalyst. This catalyst exhibits highly efficient, size-selective, and recyclable catalytic activity for the Suzuki–Miyaura cross-coupling reaction. This strategy is also useful for the covalent modification of amine-tagged defective Ni2(DOBPDC), an expanded analogue of MOF-74.
Lim, Jaewoong,Lee, Seonghwan,Ha, Hyeonbin,Seong, Junmo,Jeong, Seok,Kim, Min,Baek, Seung Bin,Lah, Myoung Soo
supporting information
p. 9296 - 9300
(2021/03/09)

CNN Palladium(II) Pincer Complexes Containing N-Substituted Monoanionic and Dianionic Guanidinate Ligands: Syntheses, Structural Aspects, and Their Utility in Suzuki-Miyaura Coupling Reactions
The reactions of guanidines [(ArNH)(ArN=)CN(H)(C(O)Py-2)] (Ar = 2-RC6H4; R = Me (1) and CF3 (2)) with Pd(OC(O)R′)2 (R′ = Me, tBu and CF3) were studied with a view aimed at understanding the influence of substituent effects upon the nature of the resulting products. The reactions of 1 with Pd(OC(O)R′)2 (R′ = Me and CF3) in toluene at 65 °C afforded [Pd{κ3(C,N,N)}(OC(O)R′)] (R′ = Me (3) and CF3 (4)), while the analogous reaction involving 1 and Pd(OC(O)tBu)2 afforded [Pd{κ3(C,N,N)}(μ-OC(O)tBu)Pd{κ3(C,N,N)}] (5). The analogous reactions of 2 with Pd(OC(O)R′)2 (R′ = Me, tBu and CF3) afforded [Pd{κ3(C,N,N)}(μ-OC(O)R′)Pd{κ3(C,N,N)}] (R′ = Me (6) and tBu (7)) and [Pd{κ3(C,N,N)}(OC(O)CF3)] (8), respectively. Complexes 5-7 were treated with 2 equiv of Lewis bases, L at RT to afford [Pd{κ3(C,N,N)}(L)] [L = PPh3(9), 4-aminopyridine (10 and 11), and MeCN (12)]. The mechanisms of formation of new complexes were proposed. Complex 3 was treated with 12 in the presence of excess of NaOC(O)tBu in CHCl3 under reflux condition to afford a mixed Pd(II) pincer, [Pd{κ3(C,N,N)}(μ-OC(O)tBu)Pd{κ3(C,N,N)}] (15), and this observation indirectly supports the mechanism proposed for the formation of 5-7. The mechanisms of formation of 9-12 were verified by in situ reaction involving 7 and PPh3 (1 and 2 equiv) through 19F NMR spectroscopy. The new compounds were fully characterized, and molecular structures of 1, 3·C7H8, 4-6, 8·C7H8, 9, and 10·H2O were determined by SCXRD. The CNN tridentate guanidinate ligands were present in monoanionic (3·C7H8, 4 and 8·C7H8), mono- and dianionic (5 and 6), and dianionic (9 and 10·H2O) forms, and hence the structures of 5 and 6 are unprecedented. Complex 3·C7H8 was used as an efficient catalyst in Suzuki-Miyaura reactions involving sterically hindered aryl bromides and aryl boronic acids.
Sinha, Nitish Kumar,Thirupathi, Natesan
p. 3535 - 3549
(2021/11/12)

NiFe2O4@SiO2@ZrO2/SO42-/Cu/Co nanoparticles: A novel, efficient, magnetically recyclable and bimetallic catalyst for Pd-free Suzuki, Heck and C-N cross-coupling reactions in aqueous media
The novel heterogeneous bimetallic nanoparticles of Cu-Co were synthesized based on magnetic nanoparticles, and the magnetic nanocatalyst was characterized by XRD, FE-SEM, EDX mapping, BET, TEM, HRTEM, FTIR, TGA, and VSM. This catalyst was successfully applied as a recyclable magnetically catalyst in Heck, Suzuki, and C-N cross-coupling reactions with various aryl halides (iodides, bromides, and chlorides as challengeable substrates), with olefins, phenylboronic acid, and amines, respectively. We considered the rise of synergetic effects from the different Lewis acid and Br?nsted acid sites present in the catalyst. The catalyst was synthesized with cheap, available materials and a simple synthesis method. The catalyst can be separated easily using an external magnet. It was recycled for more than ten runs without a sensible loss of its catalytic activity, and no significant leaching of the Cu and Co quantity was observed. The significant benefits of the method are high-level generality, simple operation, and there are no heavy metals and toxic solvents. This is a quick, easy, efficacious and environmentally friendly protocol, and no by-products are formed in the reaction. These features make it an appropriate practical alternative protocol. In comparison with recent works, the other advantage of this catalyst is the synthesis of a wide variety of C-C and C-N bond derivatives (more than 40 derivatives). The other significant advantage is the low temperature of the reaction and the use of the least possible amount of the catalyst (0.003 g). The efficiency was good to excellent and the catalyst selectivity has been high. We aspire that our study inspires more interest to design novel catalysts based on using low-cost metal ions (such as cobalt and copper) in the cross-coupling reactions. This journal is
Alavi G., Seyyedeh Ameneh,Nasseri, Mohammad Ali,Kazemnejadi, Milad,Allahresani, Ali,Hussainzadeh, Mahdi
p. 7741 - 7757
(2021/05/13)

Triptycene ring metal palladium compound and application thereof
The invention discloses a triptycene cyclometalated palladium compound and an application thereof. The triptycene cyclometalated palladium compound has the following general formula, wherein three RAscan be the same or different and are respectively and independently expressed as R1-(Z1-A1-Z2)x-,wherein the three RBs can be the same or different and are respectively and independently expressed asR2-(Z3-A2-Z4)y-, the two RCs may be the same or different, each independently expressed as R3-(Z5-A3-Z6)z-. The triptycene cyclometalated palladium compound provided by the invention has a triptycenelarge-steric-hindrance group, and can stabilize a zero-valent palladium intermediate in a catalytic cycle, so that the catalytic efficiency is improved, the use amount of a catalyst can be reduced tobe less than ten thousandth, and the compound is simple in synthesis step, high in yield, relatively low in cost and suitable for various substrates, and the method has an important application valuefor researching the progress and application of the coupling reaction.
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Paragraph 0085-0092

(2021/02/24)

NaI/PPh3-Mediated Photochemical Reduction and Amination of Nitroarenes
A mild transition-metal- and photosensitizer-free photoredox system based on the combination of NaI and PPh3 was found to enable highly selective reduction of nitroarenes. This protocol tolerates a broad range of reducible functional groups such as halogen (Cl, Br, and even I), aldehyde, ketone, carboxyl, and cyano. Moreover, the photoredox catalysis with NaI and stoichiometric PPh3 provides also an alternative entry to Cadogan-type reductive amination when o-nitrobiarenes were used.
Qu, Zhonghua,Chen, Xing,Zhong, Shuai,Deng, Guo-Jun,Huang, Huawen
supporting information
p. 5349 - 5353
(2021/07/21)

Cyclic (Alkyl)(amino)carbene Ligand-Promoted Nitro Deoxygenative Hydroboration with Chromium Catalysis: Scope, Mechanism, and Applications
Transition metal catalysis that utilizes N-heterocyclic carbenes as noninnocent ligands in promoting transformations has not been well studied. We report here a cyclic (alkyl)(amino)carbene (CAAC) ligand-promoted nitro deoxygenative hydroboration with cost-effective chromium catalysis. Using 1 mol % of CAAC-Cr precatalyst, the addition of HBpin to nitro scaffolds leads to deoxygenation, allowing for the retention of various reducible functionalities and the compatibility of sensitive groups toward hydroboration, thereby providing a mild, chemoselective, and facile strategy to form anilines, as well as heteroaryl and aliphatic amine derivatives, with broad scope and particularly high turnover numbers (up to 1.8 × 106). Mechanistic studies, based on theoretical calculations, indicate that the CAAC ligand plays an important role in promoting polarity reversal of hydride of HBpin; it serves as an H-shuttle to facilitate deoxygenative hydroboration. The preparation of several commercially available pharmaceuticals by means of this strategy highlights its potential application in medicinal chemistry.
Zhao, Lixing,Hu, Chenyang,Cong, Xuefeng,Deng, Gongda,Liu, Liu Leo,Luo, Meiming,Zeng, Xiaoming
supporting information
p. 1618 - 1629
(2021/01/25)

Synthesis of Stannylated Aryl Imines and Amines via Aryne Insertion Reactions into Sn?N Bonds
The reaction of in situ generated arynes with stannylated imines to provide ortho-stannyl-aniline derivatives is reported. The readily prepared trimethylstannyl benzophenone imine is introduced as an efficient reagent to realize the aryne σ-insertion reaction. The imine functionality is an established N-protecting group and insertions proceed with good yields and good to excellent regioselectivities. The product anilines are valuable starting materials for follow-up chemistry thanks to the rich chemistry offered by the trimethylstannyl moiety.
Kran, Eva,Mück-Lichtenfeld, Christian,Daniliuc, Constantin G.,Studer, Armido
supporting information
p. 9281 - 9285
(2021/05/31)

Modular Tandem Mizoroki-Heck/Reductive Heck Reactions to Construct Fluorenes from Cyclic Diaryliodoniums
Starting from cyclic diaryliodoniums and terminal alkenes, a diverse set of fluorenes is conveniently constructed. The reactions catalyzed by palladium undergo one conventional Mizoroki-Heck reaction and one reductive Heck reaction. The scope of alkenes is general, leading to 29 fluorenes which would expand the structural diversity of fluorene reservoir. (Figure presented.).
Peng, Xiaopeng,Yang, Yang,Luo, Bingling,Wen, Shijun,Huang, Peng
supporting information
p. 222 - 226
(2020/12/01)

Pd(II) complexes with ONN pincer ligand: Tailored synthesis, characterization, DFT, and catalytic activity toward the Suzuki-Miyaura reaction
A pincer type ONN tridentate Schiff base ligand, 2-(((pyridin-2-yl)methylimino)methyl)-6-methoxyphenol, (L1) synthesized by the condensation of 4-hydroxy-3-methoxy-benzaldehyde and (pyridin-2-yl)methanamine. The ligand L1 and the new Pd(II) heteroleptic complexes of the composition [Pd(L1)(L2)]Cl, where L2 = benzimidazole, imidazole, benzooxazol or pyridine were synthesized and characterized by a set of chemical, spectrometric and spectroscopic analyses. These complexes were named 1 to 4, respectively. The FT-IR and DFT have suggested that ligand is coordinated with metal through azomethine-N and phenolic-O and arranged in square planar fashion around the metal. Correlation coefficients value between 0.995 - 0.993 shows satisfactory agreement in theoretical and experimental 1H-NMR and 13C-NMR. Benzimidazole anchored complex 1 exhibits an excellent catalytic activity. DFT calculated the energy profile diagram of the Suzuki-Miyaura reaction.
Bagri, Sanjay Singh,Chaurasia, Bhaskar,Gaur, Pratiksha,Mehrotra, Ripul,Raidas, Mohan Lal,Shukla, Satyendra Nath
(2020/08/25)

Electrochemical Palladium-Catalyzed Intramolecular C—H Amination of 2-Amidobiaryls for Synthesis of Carbazoles
The synthesis of carbazoles based on the electrochemical Pd-catalyzed intramolecular C—H amination of 2-amidobiaryls through oxidative cross coupling has been achieved under mild reaction conditions. The reaction can be carried out in undivided cell without the addition of external chemical oxidant. Besides good functional group compatibility, the desired carbazoles can be scaled up and modified easily. Compared with previous methods, this protocol affords a simple and sustainable avenue for the construction of carbazoles.
Gao, Xinlong,Lei, Aiwen,Wang, Pan,Wang, Qingqing,Zhang, Heng,Zhang, Xiaojing
supporting information
p. 143 - 148
(2020/12/18)

Catalytic Synthesis of Dibenzazepines and Dibenzazocines by 7-Exo- and 8-Endo-Dig-Selective Cycloisomerization
The 7-exo- and 8-endo-dig-selective gold-catalyzed cycloisomerizations of 2-propargylamino biphenyl derivatives were developed. The reaction of terminal alkynes gave dibenzo[b,d]azepines by 7-exo-dig cycloisomerization. In contrast, when internal alkynes were subjected to the reaction, 8-endo-dig cycloisomerization proceeded to provide dibenzo[b,d]azocines. The nucleophilicity at the reaction site and the electron-withdrawing effect of a tosyl group were important for the present selective transformation. This protocol could be used for ynamide substrates and a silver-catalyzed reaction gave 7-exo-dig products selectively.
Ito, Mamoru,Takaki, Asahi,Okamura, Moeka,Kanyiva, Kyalo Stephen,Shibata, Takanori
supporting information
p. 1688 - 1692
(2021/03/22)

Palladium-Catalyzed [4 + 3] or [2 + 2 + 3] Annulation via C-H Activation and Subsequent Decarboxylation: Access to Heptagon-Embedded Polycyclic Aromatic Hydrocarbons
The construction of a seven-membered ring in the polycyclic aromatic hydrocarbon skeleton remains a notoriously difficult but attractive challenge. Herein a novel palladium-catalyzed [4 + 3] decarboxylative annulation of 2-iodobiphenyls with 2-(2-halophenyl)acrylic acids is reported, which provides an efficient approach for assembling various tribenzo[7]annulenes via a C-H activation and decarboxylation process. Moreover, tribenzo[7]annulenes can be also synthesized via a [2 + 2 + 3] decarboxylative annulation strategy by employing readily available 1,2-halobenzenes, phenylboronic acids, and 2-(2-halophenyl)acrylic acids.
Yang, Xiumei,Chen, Xiahong,Xu, Yankun,Zhang, Minghao,Deng, Guobo,Yang, Yuan,Liang, Yun
supporting information
p. 2610 - 2615
(2021/04/12)

Iodine-Catalyzed Methylthiolative Annulation of 2-Alkynyl Biaryls with DMSO: A Metal-Free Approach to 9-Sulfenylphenanthrenes
An iodine-catalyzed sustainable, cost-effective, and atom-economic synthetic methodology is developed to synthesize a wide variety of valuable sulfenylphenanthrenes and polycyclic heteroaromatics in moderate to high yield through electrophilic thiolative annulation of 2-alkynyl biaryls (6-endo-dig cyclization) using methyl sulfoxides such as dimethyl sulfoxide (DMSO) as the sulfur source under transition-metal-free conditions. The transformation requires only iodine in a catalytic amount and trifluoroacetic anhydride. Notably, DMSO played multiple roles such as methylthiolating reagent, oxidant, and solvent in this reaction.
Chatterjee, Tanmay,Mukherjee, Nilanjana
p. 7881 - 7890
(2021/06/28)

α-Bromoacrylic Acids as C1 Insertion Units for Palladium-Catalyzed Decarboxylative Synthesis of Diverse Dibenzofulvenes
Herein α-bromoacrylic acids have been employed as C1 insertion units to achieve the palladium-catalyzed [4 + 1] annulation of 2-iodobiphenyls, which provides an efficient platform for the construction of diverse dibenzofulvenes. This protocol enables the formation of double C(aryl)-C(vinyl) bonds via a C(vinyl)-Br bond cleavage and decarboxylation. It is particularly noteworthy that the method features a broad substrate scope, and various interesting frameworks, such as bridged ring, fused (hetero)aromatic ring, and divinylbenzene, can be successfully incorporated into the products.
Zhang, Minghao,Deng, Wenbo,Sun, Mingjie,Zhou, Liwei,Deng, Guobo,Liang, Yun,Yang, Yuan
supporting information
p. 5744 - 5749
(2021/08/18)

Atmosphere-Controlled Palladium-Catalyzed Divergent Decarboxylative Cyclization of 2-Iodobiphenyls and α-Oxocarboxylic Acids
A novel palladium-catalyzed divergent decarboxylative cyclization of 2-iodobiphenyls and α-oxocarboxylic acids utilizing the atmosphere as a controlled switch is reported. Under the protection of a nitrogen atmosphere, tribenzotropones are synthesized by a [4 + 3] decarboxylative cyclization. Employing a palladium/O2 system enables a [4 + 2] decarboxylative cyclization to assemble triphenylenes. Notably, preliminary mechanistic studies indicate that the formation of triphenylenes involves a double decarboxylation.
Zhou, Liwei,Sun, Mingjie,Zhou, Fengru,Deng, Guobo,Yang, Yuan,Liang, Yun
supporting information
p. 7150 - 7155
(2021/09/18)

Palladium-Catalyzed C-H Amination/[2 + 3] or [2 + 4] Cyclization via C(sp3or sp2)-H Activation
This report describes a palladium-catalyzed Catellani reaction consisting of amination/[2 + 3] or [2 + 4] cyclization via a carboxylate ligand-exchange strategy. This method effectively activates ortho-substituents that avoid a second C-H palladation. The scope of substrates was broad, o-methyl-substituted iodoarenes were applied to the reaction smoothly, and o-phenyl-substituted iodoarenes can also be obtained by this method. In terms of mechanism, density functional theory calculations proved the sequence of the key five-membered aryl-norbornene-palladacycle intermediate formation and C(sp3 or sp2)-H activation.
An, Yang,Ding, Ya-Nan,Gou, Xue-Ya,Li, Qiao,Li, Yuke,Liang, Yong-Min,Zhang, Xiao-Yan,Zhang, Zhe
supporting information
p. 7961 - 7965
(2021/10/25)

Analysis of the Orbital and Electrostatic Contributions to the Lone Pair-Aromatic Interaction Using Molecular Rotors
The attractive interaction between carbonyl oxygens and the π-face of aromatic surfaces was studied using N-phenylimide molecular rotors. The C=O···Ar interactions could stabilize the transition states but were half the strength of comparable C=O···C=O interactions. The C=O···Ar interaction had a significant electrostatic component but only a small orbital delocalization component.
Karki, Ishwor,Li, Ping,Madukwe, Daniel O.,Shimizu, Ken D.,Tibbetts, Gabriel S.,Vik, Erik C.
supporting information
p. 8179 - 8182
(2021/11/13)

Synthesis of Indoles by Reductive Cyclization of Nitro Compounds Using Formate Esters as CO Surrogates
Alkyl and aryl formate esters were evaluated as CO sources in the Pd- and Pd/Ru-catalyzed reductive cyclization of 2-nitrostyrenes to give indoles. Whereas the use of alkyl formates requires the presence of a ruthenium catalyst such as Ru3(CO)12, the reaction with phenyl formate can be performed by using a Pd/phenanthroline complex alone. Phenyl formate was found to be the most effective CO source and the desired products were obtained in excellent yields, often higher than those previously reported using pressurized CO. The reaction tolerates many functional groups, including sensitive ones like a free aldehydic group or a pendant pyrrole. Detailed experiments and kinetic studies allow to conclude that the activation of phenyl formate is base-catalyzed and that the metal doesn't play a role in the decarbonylation step. The reactions can be performed in a single thick-walled glass tube with as little as 0.2 mol-% palladium catalyst and even on a 2 g scale. The same protocol can be extended to other nitro compounds, affording different heterocycles.
Ahmed Fouad, Manar,Ferretti, Francesco,Formenti, Dario,Milani, Fabio,Ragaini, Fabio
supporting information
p. 4876 - 4894
(2021/09/20)

Synthesis of Substituted Anilines from Cyclohexanones Using Pd/C-Ethylene System and Its Application to Indole Synthesis
The synthesis of anilines and indoles from cyclohexanones using a Pd/C-ethylene system is reported. A simple combination of NH4OAc and K2CO3 under nonaerobic conditions was found to be the most suitable to perform this reaction. Hydrogen transfer between cyclohexanone and ethylene generates the desired products. The reaction tolerates a variety of substitutions on the starting cyclohexanones.
Maeda, Katsumi,Matsubara, Ryosuke,Hayashi, Masahiko
supporting information
p. 1530 - 1534
(2021/03/08)

Selective primary aniline synthesis through supported Pd-catalyzed acceptorless dehydrogenative aromatization by utilizing hydrazine
By utilizing hydrazine (N2H4) as the nitrogen source in the presence of a hydroxyapatite-supported Pd nanoparticle catalyst (Pd/HAP), various primary anilines can be selectively synthesized from cyclohexanonesviaacceptorless dehydrogenative aromatization. The strong nucleophilicity of N2H4and the stability of the hydrazone intermediates can effectively suppress the formation of the undesired secondary aniline byproducts.
Lin, Wei-Chen,Yatabe, Takafumi,Yamaguchi, Kazuya
supporting information
p. 6530 - 6533
(2021/07/07)

Method for preparing 2-aminobiphenyl
The invention provides a preparation method of 2-aminobiphenyl. The preparation method comprises the following step: under the catalytic action of an N-heterocyclic carbene coordinated palladium complex containing a carbohydrate unit, carrying out cross coupling reaction on 2-bromoaniline and phenyl boronic acid to generate 2-aminobiphenyl. The method is characterized in that an N-heterocyclic carbene coordinated palladium complex containing an alpha-D-altropyranose unit, a beta-D-altropyranose unit, an alpha-D-idopyranose unit or a beta-D-idopyranose carbohydrate unit is used as a catalyst, wherein an imidazolyl nitrogen atom of the N-heterocyclic carbene coordinated palladium complex is connected to the 2-position or 3-position of a pyranoid ring.
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Paragraph 0015

(2020/05/05)

L-lysine-Pd Complex Supported on Fe3O4 MNPs: a novel recoverable magnetic nanocatalyst for Suzuki C-C Cross-Coupling reaction
In this work, L-lysine-Pd Complex, immobilized onto the surface of Fe3O4 MNPs, was successfully prepared via simple and inexpensive procedure. The prepared nanocatalyst was considered as a robust and clean nano-reactor catalyst for the Suzuki and Heck C-C Cross-Coupling reactions in water as the green condition. This eco-friendly heterogeneous catalyst was characterized by Fourier transform infrared spectroscopy (FT-IR), X-Ray Diffractometer (XRD), energy-dispersive X-ray spectroscopy (EDS), inductively coupled plasma atomic emission spectroscopy (ICP), X-ray mapping, BET, thermogravimetric analysis (TGA), vibrating sample magnetometer (VSM), scanning electron microscopy (SEM) and Transmission electron microscopy (TEM) techniques. The use of a green medium, easy separation and workup, excellent reusability of the nanocatalyst and short reaction time are some outstanding advantages of this method.
Ashraf, Muhammad Aqeel,Liu, Zhenling,Zhang, Dangquan,Alimoradi, Ashkan
(2020/04/23)

Monosubstituted, Anionic Imidazolyl Ligands from N?H NHC Precursors and Their Activity in Pd-Catalyzed Cross-Coupling Reactions
We report that treatment of several 2-diphenylphosphinoimidazoles with Pd(II) salts generates monosubstituted N?H NHC?Pd complexes via insertion into the C?P bond. Removal of the N?H proton in situ leads to anionic (X-type) or imidazolyl-Pd complexes that are highly stable and catalytically active, achieving up to 340,000 turnovers at 1 ppm catalyst loading in Suzuki-Miyaura reactions. DFT-calculated Tolman electronic parameters for the sterically small ligands suggest that these ligands are significantly more donating than traditional NHCs, which provides a rationale for rapid cross-coupling catalysis. Excellent reactivity is also demonstrated in Sonogashira reactions. (Figure presented.).
Clark, Kyle J.,Ess, Daniel H.,Jensen, Christopher A.,Kenney, Karissa C.,Larson, Alexandra J. S.,Martinez, Erin E.,Michaelis, David J.,Nazari, S. Hadi,Smith, Stacey J.,Valdivia-Berroeta, Gabriel A.
supporting information

(2020/07/06)

Synthesis and catalytic activity of cationic dinuclear palladium (II) complexes supported by thioether ligands containing two di-(2-picolyl) amine arms
The design, synthesis and characterization of a series of dithioether ligands featuring two di-(2-picolyl)amine arms (2a–2d) and their corresponding cationic dinuclear palladium (II) complexes (3a–d) are reported. Crystal structures of ligand 2b and complexes 3b and 3d were determined by X-ray diffraction studies. The molecular structures of 3b and 3d display each of the two di-(2-picolyl)amine fragments coordinated to one palladium(II) atom in a (κ3-N,N,N) tridentate fashion and with the cationic metal centers displaying square-planar geometries. Weak interactions between the metal centers and the thioether fragments are observed. All bimetallic complexes 3a–d were tested as catalytic precursors in the Suzuki couplings of different o- or p-substituted iodo- or bromoaryls with boronic acids. The overall catalytic results indicate that complex 3b is the best precursor of the series demonstrating even more efficient performance compared to commercial palladium sources such as Pd(OAc)2 and the Nájera Catalysts.
Andrade-López, Noemi,González-Montiel, Simplicio,Martínez-Otero, Diego,Salazar-Pereda, Verónica,Sandoval-Chávez, César Ignacio,Velázquez-Jiménez, René
(2020/03/13)

Cu(OAc)2 entrapped on ethylene glycol-modified melamine–formaldehyde polymer as an efficient heterogeneous catalyst for Suzuki–Miyaura coupling reactions
This work is described as an environmental friendly approach for Cu(OAc)2 entrapped on ethylene glycol-modified melamine–formaldehyde-based polymeric material (Cu@MCOP) which has been successfully synthesized by simple approaches using commercially available starting materials via solvothermal techniques and without using any toxic reagents and chemicals. The structural, morphological, physicochemical characteristics and catalytic activity of the heterogeneous catalyst (Cu@MCOP) were analyzed by various instrumental methods including powder X-ray diffraction, FT-IR, UV-DRS, X-ray photoelectron spectroscopy, SEM and elemental mapping which have been used to authenticate the polymeric materials Cu@MCOP. The catalytic performance of Cu@MCOP as solid heterogeneous catalyst was evaluated in synthesis of various biphenyl derivatives through Suzuki–Miyaura cross-coupling reactions of various aryl halides with substituted organoboranes under normal reaction conditions. Furthermore, the copper catalyst was easily available, low cost, cheap and best instead of palladium, which shows good catalytic activity and excellent yield (up to 86%); the catalyst can be separated easily and recycled for more than five times. Graphic abstract: [Figure not available: see fulltext.].
Sadhasivam, Velu,Sankar, Balakrishnan,Elamathi, Ganesan,Mariyappan, Mathappan,Siva, Ayyanar
p. 681 - 700
(2019/11/03)

Cascade One-Pot Synthesis of Orange-Red-Fluorescent Polycyclic Cinnolino[2,3-f]phenanthridin-9-ium Salts by Palladium(II)-Catalyzed C?H Bond Activation of 2-Azobiaryl Compounds and Alkenes
Quaternary ammonium salts were synthesized in moderate to good yields through double oxidative C?H bond activation on azobenzenes. The mechanism of the highly regioselective reaction of 2-azobiaryls with alkenes to give orange-red-fluorescent cinnolino[2,
Jayakumar, Jayachandran,Vedarethinam, Guganchandar,Hsiao, Huan-Chang,Sun, Shang-You,Chuang, Shih-Ching
supporting information
p. 689 - 694
(2019/11/22)

Single monodentate N-donor ligands versus multi-ligand analogues in Pd(II)-catalysed C–C coupling at reduced temperatures
Deployment of reduced operational temperatures is industrially beneficial and use of the highly efficient, phosphine-based precatalysts is limited by their high costs and inaccessible preparation procedures. In order to study of the influence of coordination environments on catalyst reactivities at reduced temperatures, design of palladium(II) complexes bearing single monodentate N-donor ligands was considered necessary. Consequently, dichloridopalladium(II) complexes of 2-(thiophen-2-yl)-1H-imidazole ligands (1–8), 2,4,5-triphenyloxazole (9) and 2-(1H-imidazol-2-yl)pyridine (10) have been prepared, structurally characterized and studied as N-stabilized precatalysts. Ligand donor strengths were spectroscopically estimated by protonation-deprotonation equilibria. The palladium(II) complexes were obtained in three coordination environments; (i) the mono-ligand complexes bearing trans-solvent co-ligands (PdL.acn and PdL.dmf), (ii) the chlorido-bridged dimers μ-(PdL)2 and (iii) the trans-bis-ligand PdL2 complexes. Considering ambient temperature operations, the catalysis outcomes obtained for the monodentate mono-ligand coordination designs represent an improvement in terms of temperature and reaction time relative to previously reported N-stabilized palladium precatalysts. The mono-ligand pre-catalysts efficiently generate living active palladium species from 40 °C while a trans-bis-ligand phosphine-based pre-catalyst analogue PdI2(PPh3)2 displayed no yield under the same temperature conditions. Trans-bis-ligand coordination is observed to utterly hinders catalyst efficiencies at the studied temperatures and preformed mono-ligand complexes of mono-dentate N-donors provided positive ligand effects while in situ catalyst generation failed. Therefore, the use of multiple ligand equivalents should be discouraged.
Eseola, Abiodun Omokehinde,G?rls, Helmar,Orighomisan Woods, Joseph Anthony,Plass, Winfried
(2020/03/27)

Simple reversible fixation of a magnetic catalyst in a continuous flow system: Ultrafast reduction of nitroarenes and subsequent reductive amination using ammonia borane
Continuous reductive amination of aldehydes with nitroarenes over a Pd-Pt-Fe3O4 catalyst was performed. We used NH3BH3 as not only a hydrogen source for nitro reduction, but also a reductant for imine reduction. Secondary aromatic amines were obtained in the continuous flow reaction in good to excellent yields.
Byun, Sangmoon,Cho, Ahra,Kang, Dong Yun,Kim, B. Moon,Kim, Ha Joon,Kim, Hong Won,Kim, Seong Min,Lei, Cao,Park, Jin Kyoon
p. 944 - 949
(2020/03/11)

General and selective synthesis of primary amines using Ni-based homogeneous catalysts
The development of base metal catalysts for industrially relevant amination and hydrogenation reactions by applying abundant and atom economical reagents continues to be important for the cost-effective and sustainable synthesis of amines which represent highly essential chemicals. In particular, the synthesis of primary amines is of central importance because these compounds serve as key precursors and central intermediates to produce value-added fine and bulk chemicals as well as pharmaceuticals, agrochemicals and materials. Here we report a Ni-triphos complex as the first Ni-based homogeneous catalyst for both reductive amination of carbonyl compounds with ammonia and hydrogenation of nitroarenes to prepare all kinds of primary amines. Remarkably, this Ni-complex enabled the synthesis of functionalized and structurally diverse benzylic, heterocyclic and aliphatic linear and branched primary amines as well as aromatic primary amines starting from inexpensive and easily accessible carbonyl compounds (aldehydes and ketones) and nitroarenes using ammonia and molecular hydrogen. This Ni-catalyzed reductive amination methodology has been applied for the amination of more complex pharmaceuticals and steroid derivatives. Detailed DFT computations have been performed for the Ni-triphos based reductive amination reaction, and they revealed that the overall reaction has an inner-sphere mechanism with H2metathesis as the rate-determining step.
Beller, Matthias,Chandrashekhar, Vishwas G.,Jagadeesh, Rajenahally V.,Jiao, Haijun,Murugesan, Kathiravan,Wei, Zhihong
p. 4332 - 4339
(2020/05/18)

Exploration of Fragment Binding Poses Leading to Efficient Discovery of Highly Potent and Orally Effective Inhibitors of FABP4 for Anti-inflammation
Fatty-acid binding protein 4 (FABP4) is a promising therapeutic target for immunometabolic diseases, while its potential for systemic inflammatory response syndrome treatment has not been explored. Here, a series of 2-(phenylamino)benzoic acids as novel and potent FABP4 inhibitors are rationally designed based on an interesting fragment that adopts multiple binding poses within FABP4. A fusion of these binding poses leads to the design of compound 3 with an ?460-fold improvement in binding affinity compared to the initial fragment. A subsequent structure-aided optimization upon 3 results in a promising lead (17) with the highest binding affinity among all the inhibitors, exerting a significant anti-inflammatory effect in cells and effectively attenuating a systemic inflammatory damage in mice. Our work therefore presents a good example of lead compound discovery derived from the multiple binding poses of a fragment and provides a candidate for development of drugs against inflammation-related diseases.
Su, Haixia,Zou, Yi,Chen, Guofeng,Dou, Huixia,Xie, Hang,Yuan, Xiaojing,Zhang, Xianglei,Zhang, Naixia,Li, Minjun,Xu, Yechun
p. 4090 - 4106
(2020/05/20)

Regiospecific Introduction of Halogens on the 2-Aminobiphenyl Subunit Leading to Highly Potent and Selective M3 Muscarinic Acetylcholine Receptor Antagonists and Weak Inverse Agonists
Muscarinic M3 receptor antagonists and inverse agonists displaying high affinity and subtype selectivity over the antitarget M2 are valuable pharmacological tools and may enable improved treatment of chronic obstructive pulmonary disease (COPD), asthma, or urinary incontinence. On the basis of known M3 antagonists comprising a piperidine or quinuclidine unit attached to a biphenyl carbamate, 5-fluoro substitution was responsible for M3 subtype selectivity over M2, while 3′-chloro substitution substantially increased affinity through a σ-hole interaction. Resultantly, two piperidinyl-and two quinuclidinium-substituted biphenyl carbamates OFH243 (13n), OFH244 (13m), OFH3911 (14n), and OFH3912 (14m) were discovered, which display two-digit picomolar affinities with Ki values from 0.069 to 0.084 nM, as well as high selectivity over the M2 subtype (46-to 68-fold). While weak inverse agonistic properties were determined for the biphenyl carbamates 13m and 13n, neutral antagonism was observed for 14m and 14n and tiotropium under identical assay conditions.
Fischer, Oliver,Hofmann, Josefa,Rampp, Hannelore,Kaindl, Jonas,Pratsch, Gerald,Bartuschat, Amelie,Taudte, R. Verena,Fromm, Martin F.,Hübner, Harald,Gmeiner, Peter,Heinrich, Markus R.
p. 4349 - 4369
(2020/06/08)

Regiospecific Introduction of Halogens on the 2-Aminobiphenyl Subunit Leading to Highly Potent and Selective M3 Muscarinic Acetylcholine Receptor Antagonists and Weak Inverse Agonists
Muscarinic M3 receptor antagonists and inverse agonists displaying high affinity and subtype selectivity over the antitarget M2 are valuable pharmacological tools and may enable improved treatment of chronic obstructive pulmonary disease (COPD), asthma, or urinary incontinence. On the basis of known M3 antagonists comprising a piperidine or quinuclidine unit attached to a biphenyl carbamate, 5-fluoro substitution was responsible for M3 subtype selectivity over M2, while 3′-chloro substitution substantially increased affinity through a σ-hole interaction. Resultantly, two piperidinyl- A nd two quinuclidinium-substituted biphenyl carbamates OFH243 (13n), OFH244 (13m), OFH3911 (14n), and OFH3912 (14m) were discovered, which display two-digit picomolar affinities with Ki values from 0.069 to 0.084 nM, as well as high selectivity over the M2 subtype (46-to 68-fold). While weak inverse agonistic properties were determined for the biphenyl carbamates 13m and 13n, neutral antagonism was observed for 14m and 14n and tiotropium under identical assay conditions.
Fischer, Oliver,Hofmann, Josefa,Rampp, Hannelore,Kaindl, Jonas,Pratsch, Gerald,Bartuschat, Amelie,Taudte, R. Verena,Fromm, Martin F.,Hübner, Harald,Gmeiner, Peter,Heinrich, Markus R.
p. 4349 - 4369
(2020/06/08)

A self-assembling NHC-PD-loaded calixarene as a potent catalyst for the Suzuki-Miyaura cross-coupling reaction in water
Nanoformulated calix[8]arenes functionalized with N-heterocyclic carbene (NHC)palladium complexes were found to be efficient nano-reactors for Suzuki-Miyaura cross-coupling reactions of water soluble iodo- and bromoaryl compounds with cyclic triol arylborates at low temperature in water without any organic co-solvent. Combined with an improved one-step synthesis of triol arylborates from boronic acid, this remarkably efficient new tool provided a variety of 40-arylated phenylalanines and tyrosines in good yields at low catalyst loading with a wide functional group tolerance.
Abdellah, Ibrahim,Couvreur, Patrick,Desma?le, Didier,Huc, Vincent,Martini, Cyril,Mougin, Julie,Pecnard, Shannon,Peramo, Arnaud
(2020/04/10)

N,N′-bridged binuclear NHC palladium complexes: A combined experimental catalytic and computational study for the Suzuki reaction
This work examines how N-donor bridged spacer ligands affect N-heterocyclic carbene (NHC) palladium complexes catalytic activities for Suzuki coupling reaction. Different degrees of structural flexibility binuclear NHC palladium complexes were synthesized. The more flexible nitrogen-based alkyl chain ligand shows similar performance with cycloamine counterparts in the Suzuki coupling reaction. Suzuki coupling examples were used in air and ambient temperature to reach moderate to completion yields in short time. Density functional theory calculations showed that the chelate effect, associated with a single Pd complex mechanism, plays a fundamental role in the pre-catalysis stage, supporting a reasonable of the kinetic activity observed experimentally.
Chen, Ming-Tsz,Hsieh, Bing-Yan,Liu, Yi-Hung,Wu, Kuo-Hui,Lussari, Natália,Braga, Ataualpa A.C.
(2020/07/06)

A Co-Cu bimetallic magnetic nanocatalyst with synergistic and bifunctional performance for the base-free Suzuki, Sonogashira, and C-N cross-coupling reactions in water
A novel magnetically recyclable bimetallic catalyst was prepared by anchoring imidazolium moiety and PEG chains on Fe3O4 NPs and named as Fe3O4?PEG/Cu-Co. It was found to be a powerful catalyst for the Sonogashira, Suzuki, and C-N cross-coupling reactions in water as a green solvent without the need for any external base. Fe3O4?PEG/Cu-Co was well characterized with FT-IR, FE-SEM, TEM, VSM, EDX, ICP, UV-visible, CV, and XPS analyses. Optimum ranges of parameters such as time, temperature, and amount of catalyst were investigated by Design-Expert 10.0.7 software for C-C Suzuki, Sonogashira, and C-N cross-coupling reactions to find the optimum conditions. The catalyst was compatible with a variety of aryl halides and N-arenes and gave favorable coupling products with good to high yields for all of them. Hot filtration and Hg poisoning tests involving the nanocatalyst revealed the stability, low metal leaching, and heterogeneous nature of the catalyst. Reaction mechanisms were proposed by study of the UV-visible spectra in situ as well as hydroquinone tests during the progress of reactions. In situ XPS analysis was also used to study the reaction mechanism. To prove the synergistic performance of Co and Cu in the catalyst, its various homologues were synthesized and applied to a model reaction separately, and then their catalytic activities were investigated. Finally, the catalyst could be recovered from the reaction mixture simply, and reused for several cycles with a minimum loss in catalytic activity and performance.
Allahresani, Ali,Kazemnejadi, Milad,Nasseri, Mohammad Ali,Rezazadeh, Zinat
p. 10645 - 10660
(2020/09/18)

Sun-light-driven suzuki-miyaura cross-coupling using a novel superparamagnetic metal-organic framework catalyst
A prominent catalytic activity for sun-light driven Suzuki-Miyaura cross-coupling reaction has been shown in the presence of superparamagnetic core-shell metal-organic framework (Fe3O4@Ni-Co-BTC NPs) (with particle size 10–47 nm) and unique bimetallic core-shell nanostructure). Various aryl halides with electron-donating or electron-withdrawing substituents were coupled with different arylboronic acids towards corresponding products at ambient temperature in H2O. The results of photocatalysis demonstrate that Fe3O4@Ni-Co-BTC NPs is a good photocatalyst under sun light irradiation with high efficiency, chemoselectivity and functional group tolerance. This magnetic separable nanostructured catalyst can be reused more than six times with minimal loss of catalytic activity rendering this catalyst long-term stability. The results acquired in the present study can serve as inspiration for the further exploitation of the sun-light-driven cross-coupling reaction under mild conditions.
Taraghi, Sina,Akhlaghinia, Batool,Pourali, Ali Reza
(2021/05/06)

Self-Assembled Helical Arrays for the Stabilization of the Triplet State
Room-temperature phosphorescence of metal and heavy atom-free organic molecules has emerged as an area of great potential in recent years. A rational design played a critical role in controlling the molecular ordering to impart efficient intersystem crossing and stabilize the triplet state to achieve room-temperature ultralong phosphorescence. However, in most cases, the strategies to strengthen phosphorescence efficiency have resulted in a reduced lifetime, and the available nearly degenerate singlet-triplet energy levels impart a natural competition between delayed fluorescence and phosphorescence, with the former one having the advantage. Herein, an organic helical assembly supports the exhibition of an ultralong phosphorescence lifetime. In contrary to other molecules, 3,6-phenylmethanone functionalized 9-hexylcarbazole exhibits a remarkable improvement in phosphorescence lifetime (>4.1 s) and quantum yield (11 percent) owing to an efficient molecular packing in the crystal state. A right-handed helical molecular array act as a trap and exhibits triplet exciton migration to support the exceptionally longer phosphorescence lifetime.
Babu, Sukumaran Santhosh,Chaubey, Shailendra Kumar,Gonnade, Rajesh G.,Goudappagouda,Krishnan, Retheesh,Kumar, G. V. Pavan,Mohana Kumari, Divya S.,Nayak, Rashmi,Nidhankar, Aakash D.
supporting information
p. 13079 - 13085
(2020/06/10)

Photocatalytic xanthate-based radical addition/cyclization reaction sequence toward 2-biphenyl isocyanides: Synthesis of 6-alkylated phenanthridines
A photocatalytic xanthate-based radical addition/cyclization reaction cascade toward 2-biphenylisocyanides is described as a practical and modular approach to 6-alkylated phenanthridines. The use of xanthates as radical precursors allowed the synthesis of diversely 6-substituted phenanthridines. Electrophilic radicals derived from nitriles, aromatic and aliphatic ketones, malonates, and amide derivatives, as well as radicals derived from phthalimidomethyl and benzylic derivatives were successfully introduced. The reaction proceeds under mild conditions without a stoichiometric amount of oxidant. Thirty novel phenanthridine scaffolds were synthesized with yields ranging from 24 to 76%.
López-Mendoza, Pedro,Miranda, Luis D.
supporting information
p. 3487 - 3491
(2020/05/25)

Visible-Light-Driven Difluoromethylation of Isocyanides with S-(Difluoromethyl)diarylsulfonium Salt: Access to a Wide Variety of Difluoromethylated Phenanthridines and Isoquinolines
A highly efficient approach of visible-light-driven radical difluoromethylation of isocyanides to access a wide variety of difluoromethylated phenanthridines and isoquinolines is herein described. Electrophilic S-(difluoromethyl)diarylsulfonium salt proved to be a good difluoromethyl radical precursor under photoredox catalysis. A broad range of isocyanides were tolerated to furnish the corresponding difluoromethylated phenanthridines, isoquinolines, furo[3,2-c]pyridine, and pyrido[3,4-b]indole in moderate to excellent yields under mild conditions. A plausible mechanism was also proposed.
Chen, Jia-Yi,Li, Xin,Lin, Li-Ting,Liu, Guo-Kai,Qin, Wen-Bing,Wong, Henry N. C.,Xiong, Wei
p. 10479 - 10487
(2020/09/23)

Pd-Catalyzed C(sp3)-H Biarylation via Transient Directing Group Strategy
Here, we describe a highly selective Pd-catalyzed C(sp3)-H biarylation of 2-methylbenzaldehydes using cyclic diaryliodonium salts as arylation reagents. The key strategy is the employment of tert-leucine as a bidentate transient directing group for the proximity-driven metalation to achieve reactivity and selectivity in C-H activation. Various functionalized biaryls bearing both aldehyde and iodine functional groups were prepared successfully, which could be further transformed into a wide range of compounds with potential applications in pharmaceutical chemistry and materials science.
Ding, Mingruo,Hua, Wenkai,Liu, Min,Zhang, Fengzhi
supporting information
p. 7419 - 7423
(2020/10/09)

Self-Assembled Multilayer Iron(0) Nanoparticle Catalyst for Ligand-Free Carbon-Carbon/Carbon-Nitrogen Bond-Forming Reactions
Self-assembled multilayer iron(0) nanoparticles (NPs, 6-10 nm), namely, sulfur-modified Au-supported Fe(0) [SAFe(0)], were developed for ligand-free one-pot carbon-carbon/carbon-nitrogen bond-forming reactions. SAFe(0) was successfully prepared using a well-established metal-nanoparticle catalyst preparative protocol by simultaneous in situ metal NP and nanospace organization (PSSO) with 1,4-bis(trimethylsilyl)-1,4-dihydropyrazine (Si-DHP) as a strong reducing agent. SAFe(0) was easy to handle in air and could be recycled with a low iron-leaching rate in reaction cycles.
Akiyama, Toshiki,Arisawa, Mitsuhiro,Haneoka, Hitoshi,Harada, Kazuo,Hasegawa, Jun-Ya,Honma, Tetsuo,Mashima, Kazushi,Sato, Yoshihiro,Shimoda, Shuhei,Shio, Yasunori,Suzuki, Takeyuki,Tamenori, Yusuke,Tsurugi, Hayato,Tsuruta, Kazuki,Wada, Yuki,Yamada, Makito
supporting information
p. 7244 - 7249
(2020/10/12)

Visible-Light-Induced Decarboxylative Cyclization/Hydrogenation Cascade Reaction to Access Phenanthridin-6-yl(aryl)methanol by an Electron Donor-Acceptor Complex
A novel and efficient visible-light-induced decarboxylative cyclization/hydrogenation cascade reaction of α-oxocarboxylic acids and 2-isocyanobiaryls has been developed. Without the need of any external photosensitizer, oxidant, and reductant, this method offers a mild and green approach for the synthesis of diverse alcohols in moderate to good yields. A mechanism indicated that an electron donor-acceptor complex-driven decarboxylation, radical addition/cyclization, and in situ photochemical reduction of ketones to alcohols could be involved in the reaction.
Shi, Wei,Ma, Fang,Li, Pinhua,Wang, Lei,Miao, Tao
p. 13808 - 13817
(2020/11/20)

Design, synthesis, and structure-activity relationship of 7-propanamide benzoxaboroles as potent anticancer agents
Benzoxaboroles, as a novel class of bioactive molecules with unique physicochemical properties, have been shown to possess excellent antimicrobial activities with tavaborole approved in 2014 as an antifungal drug. Although urgently needed, the investigation of benzoxaboroles as anticancer agents has been lacking so far. In this study, we report the design, synthesis, and anticancer structure-activity relationship of a series of 7-propanamide benzoxaboroles. Compounds 103 and 115 showed potent activity against ovarian cancer cells with IC50 values of 33 and 21 nM, respectively. Apoptosis was induced by these compounds and colony formation was effectively inhibited. Furthermore, they also showed excellent efficacy in ovarian tumor xenograft mouse model.
Zhang, Jiong,Zhang, Jinyi,Hao, Guiyun,Xin, Weixiang,Yang, Fei,Zhu, Mingyan,Zhou, Huchen
p. 6765 - 6784
(2019/08/20)

Palladium Palladium Nanoparticles Nanoparticles Supported Supported on β-cyclodextrin on β-Cyclodextrin Functionalised Functionalized Poly(amido Poly(amidoamine)s amine)s and their and Application Their Application in Suzuki-Miyaura in Suzuki-Miyaura Cross-Coupling Cross-Coupling Reactions Reactions
Herein, the synthesis, characterization and catalytic application of an organic-inorganic, palladium (Pd)-containing hybrid material, poly(amidoamine)-cyclodextrin (Pd@PAAs-CD), is reported as an efficient catalyst for Suzuki-Miyaura coupling reactions. The structure of Pd@PAAs-CD was confirmed by Fourier transform infrared spectroscopy (FTIR), transmission electron microscopy (TEM), scanning electron microscopy (SEM), inductively-coupled plasma atomic emission spectroscopy (ICP-AES), and 1H nuclear magnetic resonance (NMR) spectroscopy. Furthermore, an efficient protocol has been developed using Pd@PAAs-CD as the catalyst in a Suzuki-Miyaura cross-coupling reaction in an aqueous medium in high yields. By using cyclodextrin (CD) as the mediator grafted onto PAAs, the Pd nanoparticles (NPs) were dispersed and enhanced the catalytic reaction by promoting host-guest interactions with the CD. In addition, the reusability of the Pd@PAAs-CD hybrid material is demonstrated for use in multiple sequential cross-coupling reactions.
Zhang, Wei,Yao, Zi-Jian,Deng, Wei
p. 1667 - 1677
(2019/10/01)