- Structure and Properties of a Five-Coordinate Nickel(II) Porphyrin
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Axial coordination in nickel(II) porphyrins has been thoroughly investigated and is well understood. However, isolated five-coordinate nickel(II) porphyrins are still elusive after 50 years of intense research, even though they play a crucial role as intermediates in enzymes and catalysts. Herein we present the first fully stable, thoroughly characterized five-coordinate nickel(II) porphyrin in solution and in the solid state (crystal structure). The spectroscopic properties indicate pure high-spin behavior (S = 1). There are distinct differences in the NMR, UV-vis, and redox behavior compared to those of high-spin six-coordinate [with two axial ligands, such as NiTPPF10·(py)2] and low-spin four-coordinate (NiTPPF10) nickel(II) porphyrins. The title compound, a strapped nickel(II) porphyrin, allows a direct comparison of four-, five-, and six-coordinate nickel(II) porphyrins, depending on the environment. With this reference in hand, previous results were reevaluated, for example, the switching efficiencies and thermodynamic data of nickel(II) porphyrin-based spin switches in solution.
- Gutzeit, Florian,Dommaschk, Marcel,Levin, Natalia,Buchholz, Axel,Schaub, Eike,Plass, Winfried,N?ther, Christian,Herges, Rainer
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- Phosphine-free Suzuki-Miyaura reactions catalyzed by bishydrazone-Pd-complex
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Glyoxal bis(methylphenylhydrazone) 1 was prepared and examined as a ligand for the Suzuki-Miyaura cross-coupling reaction of aryl bromides and arylboronic acids. We found phosphine-free catalyst, such as Pd(OAc)2/hydrazone ligand 1 to be an eff
- Mino, Takashi,Shirae, Yoshiaki,Sakamoto, Masami,Fujita, Tsutomu
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- Fast Suzuki-Miyaura cross-coupling reaction catalyzed by the Na 2Pd2Cl6 complex with ethyl calix[4]aryl acetate at room temperature in aqueous medium under ligand-free and ambient atmosphere
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The new Na2Pd2Cl6 complex with ethyl calix[4]aryl acetate 2 was prepared simply and efficiently by the extraction of sodium ion from Na2PdCl4 aqueous solution with ethyl calix[4]aryl acetate. The structure of complex 2 could be verified by X-ray single crystal structure determination. The complex 2 was tested as catalyst in Suzuki-Miyaura cross-coupling reaction at room temperature in CH 3OH/H2O medium under ambient conditions. Using 0.2 mol% of the complex 2 in the presence of K2CO3 as base offered excellent yields in the reaction of activated and non-activated aryl bromides with aryl boronic acids within 10 min. The key for achieving a very rapid and almost quantitative coupling is probably the use of ethyl calix[4]aryl acetate possessing extended hydrophobic host cavities and surface active properties. In addition, it was found that both solvent and base had a fundamental influence on the reaction.
- Mu, Bing,Li, Jingya,Han, Zixing,Wu, Yangjie
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- Improving metabolic stability with deuterium: The discovery of GPU-028, a potent free fatty acid receptor 4 agonists
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The free fatty acid receptor 4 (FFA4) has emerged as a promising anti-diabetic target due to its function in improvement of insulin secretion and insulin resistance. The FFA4 agonist TUG-891 revealed great potential as a widely used pharmacological tool, but it has been suffered from high plasma clearance probably because the phenylpropanoic acid is vulnerable to β-oxidation. To identify metabolically stable analog without influence on physiological mechanism of TUG-891, we tried to incorporate deuterium at the α-position of phenylpropionic acid to afford compound 4 (GPU-028). As expected, GPU-028 revealed a longer half-life (T1/2 = 1.66 h), lower clearance (CL = 0.97 L/h/kg) and higher maximum plasma concentration (Cmax = 2035.23 μg/L), resulting in a 4-fold higher exposure than TUG-891. Although GPU-028 exhibited a similar agonistic activity in comparison to TUG-891, the hypoglycemic effect of GPU-028 was better than that of TUG-891 after treatment over four weeks in diet-induced obese mice. These positive results indicated that GPU-028 might be a better pharmacological tool than TUG-891 to explore physiological function of FFA4, especially on the in vivo study.
- Li, Zheng,Xu, Xue,Li, Gang,Fu, Xiaoting,Liu, Yanzhi,Feng, Yufeng,Wang, Mingyan,Ouyang, Yunting,Han, Jing
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- Au-Cavitands: Size governed arene-alkyne cycloisomerization
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With an inwardly directed reactive center and a well-defined binding pocket, Au(I) functionalized resorcin[4]arene cavitands have been shown to catalyze molecular transformations. The reactivity profiles that emerge differ from other Au(I) catalysts. The added constraint of a binding pocket gives rise to the possibility that the substrates might have to fit into the resorcinarene pocket; our hypothesis is that substrates that match the available space have different reaction outcomes than those that do not. Herein we report on the intramolecular cyclization of alkyne-aromatic substrates with variable alkynes and aromatic composition. We see that scaffold size most drastically dictates reactivity, especially when the substrate's features are particularly designed. The results of these experiments add to the veritable goldmine of information about the selectivity in catalysis that cavitands offer.
- Rusali, Lisa E.,Schramm, Michael P.
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- Electrochemical Decarboxylative Cyclization of α-Amino-Oxy Acids to Access Phenanthridine Derivatives
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Phenanthridines are a class of useful heterocycles in the field of drug development. In this work, a method via electrochemical decarboxylative cyclization of α-amino-oxy acids to access phenanthridine derivatives was developed. This reaction proceeded th
- Zhan, Yanling,Dai, Changhui,Zhu, Zitong,Liu, Ping,Sun, Peipei
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supporting information
(2022/02/07)
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- Gold Catalysts Can Generate Nitrone Intermediates from a Nitrosoarene/Alkene Mixture, Enabling Two Distinct Catalytic Reactions: A Nitroso-Activated Cycloheptatriene/Benzylidene Rearrangement
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Gold-catalyzed reactions of cycloheptatrienes with nitrosoarenes yield nitrone derivatives efficiently. This reaction sequence enables us to develop gold-catalyzed aerobic oxidations of cycloheptatrienes to afford benzaldehyde derivatives using CuCl and nitrosoarenes as co-catalysts (10-30 mol %). Our density functional theory calculations support a novel nitroso-activated rearrangement, tropylium → benzylidene. With the same nitrosoarenes, we developed their gold-catalyzed [2 + 2 + 1]-annulations between nitrosobenzene and two enol ethers to yield 5-alkoxyisoxazolidines using 1,4-cyclohexadienes as hydrogen donors.
- Cheng, Mu-Jeng,Kardile, Rahul Dadabhau,Kuo, Tung-Chun,Liu, Rai-Shung,More, Sayaji Arjun
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p. 5506 - 5511
(2021/07/31)
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- Silica-coated magnetic nanoparticles functionalized cobalt complex: a recyclable and efficient catalyst for the C?C bond formation
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In this study, the Co-based catalyst was prepared by cobalt immobilization on the surface of functionalized silica-coated magnetic NPs (Fe3O4@SiO2-CT-Co) as a magnetically core–shell nanocatalyst and characterized by FT-IR, TGA, XRD, VSM, SEM, TEM, EDX, EDX mapping, and ICP techniques and appraised in the Suzuki–Miyaura cross-coupling reaction under mild reaction conditions. The results displayed the superparamagnetic behavior of the Fe3O4 NPs core encapsulated by SiO2 shell, and the size of the particles was estimated about 30?nm. Compared with the previously reported catalysts, the engineered Fe3O4@SiO2-CT-Co catalyst provided perfect catalytic performance for the Suzuki–Miyaura cross-coupling reaction in water as a green solvent and it was much cheaper in the comparison with the traditional Pd-based catalysts. Importantly, the durability of magnetic nanocatalyst was studied and observed that it is stable under the reaction conditions and could be easily reused for at least six successive cycles without any significant decrease in its catalytic activity. Graphic abstract: [Figure not available: see fulltext.]
- Haqjow, Hanif,Raoufi, Farveh
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p. 4113 - 4128
(2021/07/26)
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- A Photochemical Intramolecular C-N Coupling Toward the Synthesis of Benzimidazole-Fused Phenanthridines
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Herein, we report a direct photochemical dehydrogenative C-N coupling of unactivated C(sp2)-H and N(sp2)-H bonds. The catalysts or additive-free transformation of 2-([1,1′-biphenyl]-2-yl)-1H-benzo[d]imidazole to benzo[4,5]imidazo[1,2-f]phenanthridine was achieved at ～350 nm of irradiation via ?-hydrogen abstraction. DFT calculations helped to understand that the N-H···πinteraction was essential for the reaction to proceed at a lower energy than expected.
- Bera, Shyamal Kanti,Boruah, Palash J.,Parida, Shraddha Saraswati,Paul, Amit K.,Mal, Prasenjit
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p. 9587 - 9602
(2021/07/26)
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- Metal-Free Electrochemical Coupling of Vinyl Azides: Synthesis of Phenanthridines and β-Ketosulfones
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We reported an efficient and environmentally benign electrochemical synthesis of phenanthridines by oxidative coupling of vinyl azides with sodium azide or benzenesulfonyl hydrazides, for the first time. The reaction conditions are mild, and no additional metal-catalyst or exogenous oxidants are needed. The protocol has broad substrate scope and high functional group tolerance. Furthermore, this green electrochemical procedure can be readily extended to the synthesis of β-ketosulfones. Gram scale reactions further demonstrate the practicability.
- Chen, Qianjin,Kong, Xianqiang,Li, Guodong,Liang, Qi,Lin, Long,Xu, Bo,Yu, Ke
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supporting information
p. 6135 - 6145
(2020/10/06)
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- 6-Arylphenanthridines from Aryl o-Biaryl Ketones with 1,1,1,3,3,3-Hexamethyldisilazane and Molecular Iodine
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Warming treatment of aryl o-biaryl ketones with 1,1,1,3,3,3-hexamethyldisilazane in the presence of Sc(OTf)3 in toluene, followed by the reaction with molecular iodine and K2CO3 in a mixture of THF and methanol at 60 °C gave the corresponding 6-arylphenanthridines in good to moderate yields. The present reaction is a one-pot method for the preparation of 6-arylphenanthridines from aryl o-biaryl ketones through the cyclization of imino-nitrogen-centered radicals that were generated from N-iodo aryl o-biaryl ketimines formed from the reaction of aryl biaryl ketimines with molecular iodine.
- Kobayashi, Eiji,Kishi, Atsushi,Togo, Hideo
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p. 7335 - 7347
(2019/11/22)
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- A Transition-Metal-Free One-Pot Cascade Process for Transformation of Primary Alcohols (RCH2OH) to Nitriles (RCN) Mediated by SO2F2
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A new transition-metal-free one-pot cascade process for the direct conversion of alcohols to nitriles was developed without introducing an “additional carbon atom”. This protocol allows transformations of readily available, inexpensive, and abundant alcohols to highly valuable nitriles.
- Jiang, Ying,Sun, Bing,Fang, Wan-Yin,Qin, Hua-Li
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supporting information
p. 3190 - 3194
(2019/05/21)
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- Base-Free Suzuki–Miyaura Coupling Reaction Using Palladium(II) Supported Catalyst in Water
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Abstract: The carbon–carbon bond formation via Suzuki–Miyaura reaction was performed in water as green solvent. Pd(OAc)2(PPh3)2 supported on magnesium hydroxide and cerium carbonate hydroxide composite was prepared and characterized by various techniques. The cross-coupling reaction of aryl halides carried out in water using mild conditions. The effects of temperature, solvents, the amount of catalyst and leaving groups were studied to find the optimization conditions for cross-coupling reaction. Various aryl halides were smoothly transformed into the biaryls in good yields. In addition, the catalyst also exhibited stability and catalytic performance in the cross-coupling of aryl halides. Graphical Abstract: [Figure not available: see fulltext.] A new approach is developed for carbon–carbon bond formation via Suzuki–Miyaura reaction.2 Pd(OAc)2(PPh3)2?supported on mixed magnesium hydroxide and cerium carbonate hydroxide were prepared and characterized by XRD, XPS, SEM–EDX techniques. The cross-coupling reaction of aryl halides can be carried out in water and under mild conditions (80 °C).
- Tomar, Ravi,Singh, Nidhi,Kumar, Neeraj,Tomar, Vartika,Chandra, Ramesh
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- Chemoselective Reduction of Sterically Demanding N,N-Diisopropylamides to Aldehydes
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A sequential one-pot process for chemoselectively reducing sterically demanding N,N-diisopropylamides to aldehydes has been developed. In this reaction, amides are activated with EtOTf to form imidates, which are reduced with LiAlH(OR)3 [R = t-Bu, Et] to give aldehydes by hydrolysis of the resulting hemiaminals. The non-nucleophilic base 2,6-DTBMP remarkably improves reaction efficiency. The combination of EtOTf/2,6-DTBMP and LiAlH(O-t-Bu)3 was found to be optimal for reducing alkyl, alkenyl, alkynyl, and 2-monosubstituted aryl N,N-diisopropylamides. In contrast, EtOTf and LiAlH(OEt)3 in the absence of base were found to be optimal for reducing extremely sterically demanding 2,6-disubstituted N,N-diisopropylbenzamides. The reaction tolerates various reducible functional groups, including aldehyde and ketone. 1H NMR studies confirmed the formation of imidates stable in water. The synthetic usefulness of this methodology was demonstrated with N,N-diisopropylamide-directed ortho-metalation and C-H bond activation.
- Xiao, Peihong,Tang, Zhixing,Wang, Kai,Chen, Hua,Guo, Qianyou,Chu, Yang,Gao, Lu,Song, Zhenlei
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p. 1687 - 1700
(2018/02/23)
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- COMPOUNDS OF PHOSPHINANES AND AZAPHOSPHINANES, A PROCESS FOR THEIR PREPARATION AND PHARMACEUTICAL COMPOSITIONS CONTAINING THEM
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Compounds of formula (I) wherein: Ak1 represents an alkyl chain, X represents —(CH2)m—, —CH(R)—, —N(R)—, —CH2—N(R)—, —N(R)—CH2— or —CH2—N(R)—CH2—, m and R are as defined in the description, R1 and R2 each represent H when X represents —(CH2)m—, —CH(R)—, —N(R)—, —CH2—N(R)— or —N(R)—CH2—, or together form a bond when X represents —CH2—N(R)—CH2—, R3 represents NH2, Cy-NH2, Cy-Ak3-NH2 or piperidin-4-yl, Cy and Ak3 are as defined in the description, R4 and R5, which may be identical or different, each represent H or F, their optical isomers, and addition salts thereof with a pharmaceutically acceptable acid. Medicinal products containing the same which are useful in treating conditions requiring a TAFIa inhibitor.
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Paragraph 0314; 0497; 0498
(2018/02/27)
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- Chromium-Catalyzed, Regioselective Cross-Coupling of C-O Bonds by Using Organic Bromides as Reactants
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We report a chromium-catalyzed cross-coupling of C-O bonds with widely accessible organic bromides as reactants for the preparation of ortho -arylated or -alkylated aromatic aldehydes at room temperature. The use of metallic magnesium is essential for the reaction to occur, giving it an advantage over previous reactions involving Grignard reagents that have to be prepared separately from organic halides before the coupling.
- Tang, Jinghua,Luo, Meiming,Zeng, Xiaoming
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supporting information
p. 2577 - 2580
(2017/09/28)
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- Low-Valent, High-Spin Chromium-Catalyzed Cleavage of Aromatic Carbon-Nitrogen Bonds at Room Temperature: A Combined Experimental and Theoretical Study
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The cleavage of aromatic carbon-nitrogen bonds catalyzed by transition metals is of high synthetic interest because such bonds are common in organic chemistry. However, few metal catalysts can be used to selectively break C(aryl)-N bonds in electronically neutral molecules. We report here the first low-valent, high-spin chromium-catalyzed cleavage of C(aryl)-N bonds in electronically neutral aniline derivatives at room temperature. By using simple and inexpensive chromium(II) chloride as precatalyst, accompanied by an imino auxiliary, the selective arylative and alkylative C-C coupling of C(aryl)-N bonds can be achieved. Crossover experiments indicate that a low-valent chromium species, formed in situ by reduction of CrCl2 with Grignard reagent, is responsible for the catalytic cleavage of C(aryl)-N bonds. DFT calculations show that facile insertion of the C(aryl)-N bond by chromium(0) can take place in a high-spin quintet (S = 2) ground state, whereas the lower-spin singlet (S = 0) and triplet (S = 1) states are inaccessible in energy. It was found that both donation of the sole paired d electrons in the d6 shell of high-spin chromium(0) to the antibonding orbital of the C(aryl)-N bond and the nitrogen ligating interaction to the metal center with its lone pair play important roles in the cleavage of the C(aryl)-N bond by the zerovalent chromium species.
- Cong, Xuefeng,Fan, Fei,Ma, Pengchen,Luo, Meiming,Chen, Hui,Zeng, Xiaoming
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p. 15182 - 15190
(2017/10/31)
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- Amide-ligand-controlled highly para-selective arylation of monosubstituted simple arenes with arylboronic acids
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Pd-catalyzed highly para-selective arylations of monosubstituted simple arenes with arylboronic acids to widely existed biaryls have been developed. Inspired by requisite amide-directing groups in reported selective oxidative couplings, amide ligands, especially DMF, are designed and found to be critical for the selectivity control in current arylations.
- Luan, Yu-Xin,Zhang, Tao,Yao, Wei-Wei,Lu, Ke,Kong, Lu-Yao,Lin, Yu-Tong,Ye, Mengchun
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supporting information
p. 1786 - 1789
(2017/02/15)
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- Silver-Catalyzed Tandem C=C Bond Hydroazidation/Radical Addition/Cyclization of Biphenyl Acetylene: One-Pot Synthesis of 6-Methyl Sulfonylated Phenanthridines
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A silver-catalyzed tandem carbon-carbon triple bond hydroazidation, radical addition, and cyclization of biphenyl acetylene is described under mild conditions, leading to the formation of 6-methyl sulfonylated phenanthridines in good yields. In this novel cascade reaction, most of the atoms are incorporated into the product without cleavage of the C=C bond. Mechanistic studies suggest the reaction should proceed through an iminyl radical reactive intermediate.
- Tang, Jiawei,Sivaguru, Paramasivam,Ning, Yongquan,Zanoni, Giuseppe,Bi, Xihe
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supporting information
p. 4026 - 4029
(2017/08/14)
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- (Biphenyl-2-alkyne) derivatives as common precursors for the synthesis of 9-iodo-10-organochalcogen-phenanthrenes and 9-organochalcogen-phenanthrenes
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In this paper, we report our results on the cyclization of (biphenyl-2-alkyne) derivatives to give two different types of phenanthrene derivatives, 9-iodo-10-organochalcogen-phenanthrenes and 9-organochalcogen-phenanthrenes. The strategy for the synthesis was based on the use of electrophilic cyclization for the preparation of 9-iodo-10-organochalcogen-phenanthrenes and iron(iii) chloride/diorganyl diselenide-mediated intramolecular cyclization to prepare 9-organochalcogen-phenanthrenes. The effects of solvent, temperature, reaction time and stoichiometry on the efficiency of cyclization reactions were investigated. The standard reaction conditions were compatible with many functional groups in the substrates, such as methyl, chlorine, fluorine and methoxyl. This protocol was efficient for diorganyl diselenides and disulfides but ineffective for diorganyl ditellurides. The resulting phenanthrenes were further functionalized through Sonogashira reactions followed by the electrophilic cyclization reaction to give the selenophene-fused aromatic compounds.
- Grimaldi, Tamiris B.,Lutz, Guilherme,Back, Davi F.,Zeni, Gilson
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p. 10415 - 10426
(2016/11/18)
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- UV light-mediated difunctionalization of alkenes with CF3SO2Na: Synthesis of trifluoromethyl phenanthrene and anthrone derivatives
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A metal-free and cost-effective protocol for UV light-mediated difunctionalization of alkenes with CF3SO2Na was developed. This strategy realized the direct formation of Csp3-CF3 and C-C bonds through a proposed
- Li, Bing,Fan, Dan,Yang, Chao,Xia, Wujiong
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supporting information
p. 5293 - 5297
(2016/07/06)
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- Regio- and Chemoselective Kumada-Tamao-Corriu Reaction of Aryl Alkyl Ethers Catalyzed by Chromium under Mild Conditions
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Acting as an environmentally benign synthetic tool, the cross-coupling reactions with aryl ethers via C-O bond activation have attracted broad interest. However, the functionalizations of C-O bonds are mainly limited to nickel catalysis, and selectivity has long been a prominent challenge when several C-O bonds are present in the one molecule. We report here the first chromium-catalyzed selective cross-coupling reactions of aryl ethers with Grignard reagents by the cleavage of C-O(alkyl) bonds. Diverse transformations were achieved using simple, inexpensive chromium(II) precatalyst combining imino auxiliary at room temperature. It offers a new avenue for buildup functionalized aromatic aldehydes with high efficiency and selectivity.
- Cong, Xuefeng,Tang, Huarong,Zeng, Xiaoming
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supporting information
p. 14367 - 14372
(2015/12/01)
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- Pinpoint-fluorinated phenanthrene synthesis based on C-F bond activation of difluoroalkenes Dedicated to Prof. Véronique Gouverneur on the occasion of her receipt of the 2014 ACS Award for Creative Work in Fluorine Chemistry.
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Treatment with a cationic palladium(II) catalyst promoted the Friedel-Crafts-type cyclization of 1,1-difluoro-1-alkenes bearing a biphenyl skeleton to afford regioselectively fluorinated (pinpoint-fluorinated) phenanthrenes via C-F bond activation. The obtained pinpoint-fluorinated phenanthrenes were observed to be organized by π-π and C-H?F interactions to exhibit columnar and layer structures in the solid state.
- Fuchibe, Kohei,Morikawa, Toshiyuki,Ueda, Ryu,Okauchi, Tatsuo,Ichikawa, Junji
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supporting information
p. 106 - 115
(2015/11/10)
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- Phosphine-Free Suzuki Cross-Coupling Reaction Using an Efficient and Reusable Pd Catalyst in an Aqueous Medium under Microwave Irradiation
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We report here an improved, highly efficient, and general method for the ligand-free Suzuki cross-coupling reaction to the synthesis of biaryls, bipyridyls, thienylpyridine, and allylphenols. Microwave irradiation of (het)aryl halides and (hetaryl, allyl)arylboronic acid N-methyl-iminodiacetic acid (MIDA) ester, using polyurea microencapsulated palladium catalyst (Pd EnCat 30), gave the coupling adducts 1a-x in excellent yields in just 10-18 min.
- Da Silva, Joaquim F. M.,Yepes Perez, Andres F.,De Almeida, Natália P.
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supporting information
p. 1995 - 2004
(2015/08/18)
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- Copper catalyzed room temperature lactonization of aromatic C-H bond: A novel and efficient approach for the synthesis of dibenzopyranones
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We have developed a novel and efficient methodology for the intramolecular aryl C-H oxidative lactonization of 2-arylbenzaldehyde using a low-cost CuCl catalyst and TBHP as the oxidant at room temperature. We applied the methodology to the synthesis of a series of dibenzopyranones.
- Singha, Raju,Dhara, Shubhendu,Ghosh, Munmun,Ray, Jayanta K.
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p. 8801 - 8805
(2015/03/03)
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- Catalytic oxidative cyclization of 2′-arylbenzaldehyde oxime ethers under photoinduced electron transfer conditions
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A series of 2′-arylbenzaldehyde oxime ethers were synthesized and shown to generate the corresponding phenanthridines upon irradiation in the presence of 9,10-dicyanoanthracene in acetonitrile. Mechanistic studies suggest that the oxidative cyclization reaction sequence is initiated by an electron transfer step followed by nucleophilic attack of the aryl ring onto the nitrogen of the oxime ether. A concave downward Hammett plot is presumably the result of a change in charge distribution in the radical cation species with strongly electron-donating substituents that yields a less electrophilic nitrogen atom and a decreased amount of cyclized product. The reaction is selective (no nitrile byproduct is formed unlike other photochemical reactions involving aldoxime ethers) as well as regiospecific when using 2′-aryl groups with metasubstituents, making this reaction a useful alternative for preparing substituted phenanthridines.
- Hofstra, Julie L.,Grassbaugh, Brittany R.,Tran, Quan M.,Armada, Nicholas R.,De Lijser, H. J. Peter
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p. 256 - 265
(2016/09/09)
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- Reduction of nitriles into aldehydes using a TMDS/V(O)(OiPr)3 reducing system
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A simple and convenient method for the chemoselective reduction of nitriles into aldehydes using a 1,1,3,3-tetramethyldisiloxane (TMDS)/ triisopropoxyvanadium(V) oxide reducing system is described. Aromatic as well as aliphatic nitriles are reduced into the corresponding aldehydes in moderate to good yields.
- Laval, Stéphane,Dayoub, Wissam,Pehlivan, Leyla,Métay, Estelle,Delbrayelle, Dominique,Mignani, Gérard,Lemaire, Marc
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- Atom-economic threefold cross-couplings of triarylbismuth reagents with 2-halobenzaldehydes and pot-economic in situ Wittig functionalizations with phosphonium salts
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In this paper we report an efficient pot-economic methodology for the synthesis of ortho-olefinated biaryls. This has been achieved through an atom-economic threefold cross-coupling of triarylbismuth reagents with 2-halobenzaldehydes followed by pot-economic in situ Wittig olefination. The overall process is a pot-economic straightforward synthesis of ortho-olefinated biaryls from 2-halobenzaldehydes, triarylbismuth reagents and phosphonium salts. This pot-economic approach was applied to the formal synthesis of medicinally important Eupomatilone-6.
- Rao, Maddali L. N.,Dhanorkar, Ritesh J.
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p. 63792 - 63806
(2015/02/19)
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- Bismuth-catalyzed synthesis of polycyclic aromatic hydrocarbons (PAHs) with a phenanthrene backbone via cyclization and aromatization of 2-(2-arylphenyl)vinyl ethers
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The reaction of 2-(2-arylphenyl)vinyl ethers in the presence of a catalytic amount of bismuth(III) triflate gave substituted phenanthrenes in excellent yields under mild reaction conditions. The reaction was also applied to the construction of other polycyclic aromatic hydrocarbons (PAHs), such as chrysene, helicene, and pyrene having a phenanthrene backbone, via regioselective cyclization. This method has the advantages of easy availability of the cyclization precursors, operational simplicity, and high reaction efficiency.
- Murai, Masahito,Hosokawa, Naoki,Roy, David,Takai, Kazuhiko
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p. 4134 - 4137
(2014/09/30)
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- Synthesis, crystal structures and catalytic activity of three cyclopalladated 6-bromo-2-ferrocenylquinoline complexes with N-heterocyclic carbenes (NHCs) and triphenylphosphine
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Three cyclopalladated 6-bromo-2-ferrocenylquinoline complexes with NHCs and PPh3 1-3 have been synthesized and characterized by elemental analysis, IR, NMR and single-crystal X-ray diffraction. Their application to Suzuki coupling of phenylboro
- Xu, Chen,Li, Hong-Mei,Wang, Zhi-Qiang,Fu, Wei-Jun
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- Synthesis, crystal structures and catalytic activity of three cyclopalladated 6-bromo-2-ferrocenylquinoline complexes with N-heterocyclic carbenes (NHCs) and triphenylphosphine
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Three cyclopalladated 6-bromo-2-ferrocenylquinoline complexes with NHCs and PPh3 1-3 have been synthesized and characterized by elemental analysis, IR, NMR and single-crystal X-ray diffraction. Their application to Suzuki coupling of phenylboronic acid co
- Xu, Chen,Li, Hong-Mei,Wang, Zhi-Qiang,Fu, Wei-Jun
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- Synthesis, crystal structures and catalytic activity of three cyclopalladated 6-bromo-2-ferrocenylquinoline complexes with N-heterocyclic carbenes (NHCs) and triphenylphosphine
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Three cyclopalladated 6-bromo-2-ferrocenylquinoline complexes with NHCs and PPh31-3 have been synthesized and characterized by elemental analysis, IR, NMR and single-crystal X-ray diffraction. Their application to Suzuki coupling of phenylboron
- Xu, Chen,Li, Hong-Mei,Wang, Zhi-Qiang,Fu, Wei-Jun
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- An efficient and new protocol for phosphine-free Suzuki coupling reaction using palladium-encapsulated and air-stable MIDA boronates in an aqueous medium
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A simple methodology that uses a system based on polyurea microencapsulated palladium (PdEnCat 30) and aryl or (2-pyridyl) MIDA boronates for Suzuki-Miyaura cross-coupling reactions of (hetero)aryl halides in water-alcohol under phosphine-free conditions was developed. This journal is the Partner Organisations 2014.
- Mendes Da Silva, Joaquim Fernando,Yepes Perez, Andres Felipe,Pinto De Almeida, Natalia
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p. 28148 - 28155
(2014/07/21)
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- Cyclometalated Pd(ii) and Ir(iii) 2-(4-bromophenyl)pyridine complexes with N-heterocyclic carbenes (NHCs) and acetylacetonate (acac): Synthesis, structures, luminescent properties and application in one-pot oxidation/Suzuki coupling of aryl chlorides containing hydroxymethyl
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A series of cyclopalladated 2-(4-bromophenyl)pyridine (bpp) complexes [Pd(bpp)(NHC)Cl] 1-3, [Pd(bpp)(acac)] 4, cyclometalated iridium(iii) complexes [Ir(bpp)2Cl]25 and [Ir(bpp)2(acac)] 6 have been synthesized and characterized. Their detailed structures have been determined by X-ray diffraction and many intermolecular C-H...X (Cl, Br, π) and π...π interactions were found in their crystals. Cyclometalated complexes 1-4 and 6 exhibit luminescence with emission peaks of 390-543 nm in dichloromethane solution under UV irradiation. Their application to coupling reactions of aryl chlorides containing hydroxymethyl was also investigated. An efficient 3/Cu cocatalyzed oxidation/Suzuki reaction for the synthesis of biarylaldehydes from chloro-phenylmethanol and arylboronic acids in air has been developed. In addition, a 6/3-cocatalyzed one-pot reaction of acetylferrocene, (2-amino-5-chlorophenyl)methanol, and arylboronic acids provided 6-aryl-2-ferrocenylquinolines in moderate to good yields.
- Xu, Chen,Li, Hong-Mei,Xiao, Zhi-Qiang,Wang, Zhi-Qiang,Tang, Si-Fu,Ji, Bao-Ming,Hao, Xin-Qi,Song, Mao-Ping
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p. 10235 - 10247
(2014/06/24)
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- Nickel-catalyzed cross-coupling of aryl fluorides and organozinc reagents
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Ni(PCy3)2Cl2 was demonstrated to effectively catalyze cross-coupling of aryl fluorides and organozinc reagents. Both electron-poor and -rich aryl fluorides can react effectively with nucleophiles including aryl-, methyl-, and benzylzinc chlorides. A wide range of substituents and functional groups are tolerated. In the presence of a directing group, PhC(O), the reaction is selective for cleavage of the C-F bond ortho to the carbonyl substituent in a difluoroarene.
- Zhu, Feng,Wang, Zhong-Xia
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p. 4285 - 4292
(2014/06/09)
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- Efficient ligand-free Hiyama cross-coupling reaction catalyzed by functionalized SBA-15-supported Pd nanoparticles
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A ligand-free Hiyama cross-coupling reaction catalyzed by functionalized SBA-15-supported Pd catalysts has been developed. The catalysts were prepared by depositing Pd nanoparticles preferentially in the micropores of the SBA-15 with hydrophobic trimethylsilyl or triphenylsilyl groups grafted on the mesopores. The nanocomposite catalysts showed excellent activities for the cross-coupling between various aryltriethoxysilanes and aryl halides under relatively mild (at 100 °C in air) reaction conditions. Moreover, the hydrophobic functionalization rendered the catalysts reusable without showing significant activity loss. The decreased activity after successive catalytic runs was attributed to a low level of Pd-leaching and a gradual collapse of mesopores of host silica. The cross-coupling protocol with the designed catalysts would be practical for use as an economical synthetic method for the construction of biphenyl derivatives. the Partner Organisations 2014.
- Huang, Shao-Hsien,Liu, Chun-Hsia,Yang, Chia-Min
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p. 2706 - 2712
(2014/05/06)
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- Suzuki-miyaura cross-coupling under solvent-free conditions
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A solvent-free reaction protocol for Suzuki-Miyaura cross-couplings was developed. (Hetero)aryl bromides and chlorides are coupled with pinacol arylboronates in high yields. The reaction is catalyzed by conventional bis(triphenylphosphine)palladium(II) chloride [(PPh3) 2PdCl2] and/or palladium(II) acetate/SPhos [Pd(OAc) 2/SPhos] under air. Copyright
- Asachenko, Andrey F.,Sorochkina, Kristina R.,Dzhevakov, Pavel B.,Topchiy, Maxim A.,Nechaev, Mikhail S.
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p. 3553 - 3557
(2014/01/06)
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- Focused pseudostatic hydrazone libraries screened by mass spectrometry binding assay: Optimizing affinities toward γ-aminobutyric acid transporter 1
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Mass spectrometric (MS) binding assays, a powerful tool to determine affinities of single drug candidates toward chosen targets, were recently demonstrated to be suitable for the screening of compound libraries generated with reactions of dynamic combinatorial chemistry when rendering libraries pseudostatic. Screening of small hydrazone libraries targeting γ-aminobutyric acid transporter 1 (GAT1), the most abundant γ-aminobutyric acid (GABA) transporter in the central nervous system, revealed two nipecotic acid derived binders with submicromolar affinities. Starting from the biphenyl carrying hit as lead structure, the objective of the present study was to discover novel high affinity GAT1 binders by screening of biphenyl focused pseudostatic hydrazone libraries formed from hydrazine 10 and 36 biphenylcarbaldehydes 11c-al. Hydrazone 12z that carried a 2′,4′-dichlorobiphenyl residue was found to be the most potent binder with low nanomolar affinity (pKi = 8.094 ± 0.098). When stable carba analogues of representative hydrazones were synthesized and evaluated, the best binder 13z was again displaying the 2′,4′- dichlorobiphenyl moiety (pKi = 6.930 ± 0.021).
- Sindelar, Miriam,Lutz, Toni A.,Petrera, Marilena,Wanner, Klaus T.
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supporting information
p. 1323 - 1340
(2013/04/10)
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- Cross dehydrogenative coupling via base-promoted homolytic aromatic substitution (BHAS): Synthesis of fluorenones and xanthones
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Cross dehydrogenative coupling reactions occurring via base-promoted homolytic aromatic substitutions (BHASs) are reported. Fluorenones and xanthones are readily prepared via CDC starting with readily available ortho-formyl biphenyls and ortho-formyl biphenylethers, respectively. The commercially available and cheap tBuOOH is used as an oxidant. Initiation of the radical chain reaction is best achieved with small amounts of FeCp2 (0.1 or 1 mol %).
- Wertz, Sebastian,Leifert, Dirk,Studer, Armido
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supporting information
p. 928 - 931
(2013/03/28)
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- A highly practical and reliable nickel catalyst for Suzuki-Miyaura coupling of aryl halides
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We disclose that [1,3-bis(diphenylphosphino)methane]nickel(II) chloride [NiCl2(dppp)] is a highly active, universally applicable, cheap, and stable catalyst for Suzuki-Miyaura cross-coupling reactions of aryl halides with a catalyst loading of lower than 1 mol%, and more notably, in the absence of extra supporting ligands. Under the optimized reaction conditions, a broad range of aryl bromides as well as the notoriously unreactive aryl chlorides, including activated, non-activated, deactivated, and heteroaromatic and sterically hindered substrates can be coupled smoothly with various boronic acids (47 examples, 48-98% yields). In addition, the transformation is tolerant of various functional groups such as ether, ester, ketone, aldehyde, cyano, and unprotected amino and hydroxy groups. Finally, the potential utilization of the methodology was further demonstrated by the gram-scale synthesis of several core structures of commercialized antihypertensive drugs and fungicides. Thus, the combination of high activity, broad applicability, cheapness, and high stability of NiCl2(dppp) presented in this work constitutes one of the few prominent catalysts which allow for practical and reliable construction of biaryls and heterobiaryls with structural diversity from readily available aryl halides and boronic acids. Copyright
- Zhao, Yu-Long,Li, You,Li, Shui-Ming,Zhou, Yi-Guo,Sun, Feng-Yi,Gao, Lian-Xun,Han, Fu-She
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supporting information; experimental part
p. 1543 - 1550
(2011/08/07)
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- First and mild synthesis of fluorene-9-malonic acid and some substituted derivatives via the intramolecular hydroarylation of 2-phenylbenzylidenemalonic acids
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Hitherto unknown fluorene-9-malonic acid and some substituted derivatives were easily synthesized in very mild conditions through the intramolecular hydroarylation of 2-phenylbenzylidenemalonic acids issued from the corresponding biphenylcarboxaldehydes.
- Chosson, Elizabeth,Rochais, Christophe,Legay, Remi,Santos, Jana Sopkova De Oliveira,Rault, Sylvain,Dallemagne, Patrick
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experimental part
p. 2548 - 2554
(2011/04/25)
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- Facile Cu(OTf)2-catalyzed preparation of 9-tosylaminofluorene derivatives from o-arylated N-tosylbenzaldimines
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The 9-tosylaminofluorene derivatives were synthesized conveniently by Cu(OTf)2-catalyzed aza-Friedel-Crafts reaction of o-arylated N-tosylbenzaldimines in high yields. This is an efficient, atom-economic, and green method.
- Yu, Xufen,Lu, Xiyan
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scheme or table
p. 2076 - 2079
(2011/05/09)
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- Ordered mesoporous organosilica with ionic-liquid framework: Au efficient and reusable support for the palladium-catalyzed suzuki-miyaura coupling reaction in water
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The preparation of a novel palladium-supported periodic mesoporous organosilica based on alkylimidazolium ionic liquid (Pd@PMO-IL) in which imidazoilium ionic liquid is uniformly distributed in the silica mesoporous framework is described. Both Pd@PMO-IL and the parent PMO-IL were characterized by N2-adsorptiondesorption, diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS), TEM, and solid-state NMR spectroscopy. We have demonstrated that Pd@PMO-IL is an efficient and reusable catalyst for the Suzuki-Miyaura coupling reaction of various types of iodo-, bromo-, and even deactivated aryl chlorides in water. It was also found that although the PMO-IL nanostructure acts as reservoir for soluble Pd species, it can also operate as a nanoscaffold to recapture the Pd nanoparticles into the mesochannels thus preventing extensive agglomeration of Pd. This observation might be attributed to the isolated ionic liquid units that effectively control the reaction mechanism by preventing Pd agglomeration and releasing and recapturing Pd nanoparticles during the reaction process. The catalyst can be recovered and reused for at least four reaction cycles without significant loss of activity.
- Karimi, Babak,Elhamifar, Dawood,Clark, James H.,Hunt, Andrew J.
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supporting information; experimental part
p. 8047 - 8053
(2010/09/07)
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- Biaryl and aryl ketone synthesis via Pd-catalyzed decarboxylase coupling of carboxylate salts with aryl triflates
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A bimetallic catalyst system has been developed that for the first time allows the decarboxylative crosscoupling of aryl and acyl carboxylates with aryl triflates. In contrast to aryl halides, these electrophiles give rise to non-coordinating anions as byproducts, which do not interfere with the decarboxylation step that leads to the generation of the carbon nucleophilic crosscoupling partner. As a result, the scope of carboxylate substrates usable in this transformation was extended from ortho-substituted or otherwise activated derivatives to a broad range of ortho-, meta-, and para-substituted aromatic carboxylates. Two alternative protocols have been optimized, one involving heating the substrates in the presence of CuI/1,10- phenanthroline (10-15 mol %) and PdI2/phosphine (23 mol%) in NMP for 1-24 h, the other involving CuI/l,10-phenanthroline (615mol%) and PdBr2/Tol-BINAP (2 mol % ) in NMP using microwave heating for 5-10 min. While most products are accessible using standard heating, the use of microwave irradiation was found to be beneficial especially for the conversion of non-activated carboxylates with functionalized aryl triflates. The synthetic utility of the transformation is demonstrated with 48 examples showing the scope and limitations of both protocols. In mechanistic studies, the special role of microwave irradiation is elucidated, and further perspectives of decarboxylase crosscouplings are discussed.
- Goossen, Lukas J.,Linder, Christophe,Rodriguez, Nuria,Lange, Paul P.
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supporting information; experimental part
p. 9336 - 9349
(2010/04/03)
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- Synthesis of biaryls and aryl ketones via microwave-assisted decarboxylative cross-couplings
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A protocol for the microwave-assisted decarboxylative cross-couplings of carboxylic acid salts with aryl halides has been developed that allows the synthesis of various biaryls and aryl ketones in high yields. After careful adaptation of the bimetallic ca
- Goossen, Lukas J.,Linder, Bettina Zimmermanns Christophe,Rodriguez, Nuria,Lange, Paul P.,Hartung, Jens
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experimental part
p. 2667 - 2674
(2009/12/31)
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- Palladium/copper-catalyzed decarboxylative cross-coupling of aryl chlorides with potassium carboxylates
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(Chemical Equation Presented) Even non-activated aryl chlorides undergo decarboxylative cross-coupling reactions in the presence of a catalyst system generated in situ from CuI, 1,10-phenanthroline, PdI2, and di(tert-butyl)biphenylphosphane. The new catalyst is useful for both the synthesis of biaryl compounds from aromatic carboxylates and the synthesis of aryl ketones from salts of α-ketocarboxylic acids (see scheme; FG=functional group; R=aryl, alkyl).
- Goossen, Lukas J.,Zimmermann, Bettina,Knauber, Thomas
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scheme or table
p. 7103 - 7106
(2009/04/12)
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- A functionalized phosphine ligand with a pentaarylbenzene moiety in palladium-catalyzed Suzuki-Miyaura coupling of aryl chlorides
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A functionalized phosphine with a pentaarylbenzene moiety was found to facilitate the palladium-catalyzed Suzuki-Miyaura coupling of aryl chlorides. The new ligand achieved high turnover numbers (up to TON 5000).
- Iwasawa, Tetsuo,Kamei, Toshinori,Watanabe, Satoshi,Nishiuchi, Masaki,Kawamura, Yasuhiko
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supporting information; experimental part
p. 7430 - 7433
(2009/05/11)
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- New cyclopentadienyl, indenyl or fluorenyl substituted phosphine compounds and their use in catalytic reactions
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The invention is directed to a phosphine compound represented by general formula (1) wherein R' and R" independently are selected from alkyl, cycloalkyl and 2-furyl radicals, or R' and R" are joined together to form with the phosphorous atom a carbon-phosphorous monocycle comprising at least 3 carbon atoms or a carbon-phosphorous bicycle; the alkyl radicals, cycloalkyl radicals, and carbon-phosphorous monocycle being unsubstituted or substituted by at least one radical selected from the group of alkyl, cycloalkyl, aryl, alkoxy, and aryloxy radicals; Cps is a partially substituted or completely substituted cyclopentadien-1-yl group, including substitutions resulting in a fused ring system, and wherein a substitution at the 1-position of the cyclopentadien-1-yl group is mandatory when the cyclopentadien-1-yl group is not part of a fused ring system or is part of an indenyl group. Also claimed is the use of these phosphines as ligands in catalytic reactions and the preparation of these phosphines.
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Page/Page column 53; 57; 59
(2008/06/13)
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- Method For Decarboxylating C-C Cross-Linking Of Carboxylic Acids With Carbon Electrophiles
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The invention relates to a method for decarboxylating C—C bond formation by reacting carboxylic salts with carbon electrophiles in the presence of transition metal compounds as catalysts. The method represents a decarboxylating C—C bond formation of carboxylic acid salts with carbon electrophiles, wherein the catalyst contains two transition metals and/or transition metal compounds, from which one is present, preferably, in the oxidation step, which are different from each other by one unit, and catalyzes a radical decarboxylation which is absorbed during the second oxidation steps, which are different from each other by two units and catalyzes the two electron processes of a C—C bond formation reaction.
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Page/Page column 4; 8
(2008/12/07)
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- A general and efficient synthesis of substituted fluorenes and heterocycle-fused indenes containing thiophene or indole rings utilizing a Suzuki-Miyaura coupling and acid-catalyzed Friedel-Crafts reactions as key steps
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A general and efficient synthesis of fluorenes or heterocycle-fused indenes including 3-thia-cyclopenta[a]indenes, 9-thia-indeno[1,2-a]indenes, 5,6-dihydroindeno[2,1-b]indoles has been developed. This methodology is realized by a multistep protocol involv
- Li, Guijie,Wang, Erjuan,Chen, Haoyi,Li, Hongfeng,Liu, Yuanhong,Wang, Peng George
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p. 9033 - 9043
(2008/12/22)
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- Synthesis and catalytic applications of sulfonate β-ketoimine and β-diimine in the Suzuki reaction in aqueous phase
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A series of sulfonated β-ketoimine and β-diimine compounds were synthesized and characterized. As supporting ligands they were used in the Suzuki cross-coupling reaction in aqueous phase with PdCl2 as catalyst. The new catalytic system can tolerate a wide range of substrates.
- Guo, Xuming,Zhou, Jin,Li, Xiaoyan,Sun, Hongjian
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scheme or table
p. 3692 - 3696
(2009/02/08)
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