- Mo–Catalyzed One-Pot Synthesis of N-Polyheterocycles from Nitroarenes and Glycols with Recycling of the Waste Reduction Byproduct. Substituent-Tuned Photophysical Properties
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A catalytic domino reduction–imine formation–intramolecular cyclization–oxidation for the general synthesis of a wide variety of biologically relevant N-polyheterocycles, such as quinoxaline- and quinoline-fused derivatives, and phenanthridines, is reported. A simple, easily available, and environmentally friendly dioxomolybdenum(VI) complex has proven to be a highly efficient and versatile catalyst for transforming a broad range of starting nitroarenes involving several redox processes. Not only is this a sustainable, step-economical as well as air- and moisture-tolerant method, but also it is worth highlighting that the waste byproduct generated in the first step of the sequence is recycled and incorporated in the final target molecule, improving the overall synthetic efficiency. Moreover, selected indoloquinoxalines have been photophysically characterized in cyclohexane and toluene with exceptional fluorescence quantum yields above 0.7 for the alkyl derivatives.
- Hernández-Ruiz, Raquel,Rubio-Presa, Rubén,Suárez-Pantiga, Samuel,Pedrosa, María R.,Fernández-Rodríguez, Manuel A.,Tapia, M. José,Sanz, Roberto
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p. 13613 - 13623
(2021/08/23)
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- Copper catalysed Gomberg-Bachmann-Hey reactions of arenediazonium tetrafluoroborates and heteroarenediazonium o-benzenedisulfonimides. Synthetic and mechanistic aspects
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Gomberg-Bachmann-Hey reactions were carried out in the presence of copper as a catalyst and gave rise to biaryls or heterobiaryls in good yields and in mild reaction conditions. A computational study of some key points of the reaction was performed. The results are coherent with the experimental data and confirm some aspects of the mechanism. The reaction free energies for the reduction in benzene by CuI of a set of 40 (hetero)arenediazonium tetrafluoroborates were calculated. Both the experiments and the calculations showed that in the coupling with substituted solvents (toluene, bromobenzene, nitrobenzene and anisole) the binding to the ortho position was always favoured.
- Antenucci, Achille,Barbero, Margherita,Dughera, Stefano,Ghigo, Giovanni
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- Highly efficient palladium-catalyzed cross-coupling of diarylborinic acids with arenediazoniums for practical diaryl synthesis
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A highly efficient cross-coupling of cost-effective diarylborinic acids with both isolatable and latent arenediazoniums, i.e. tetrafluoroborates and aryltriazenes, respectively, has been developed with a practical palladium catalyst system under base-free conditions in open flask at room temperature. A variety of electronically and sterically various biaryls, in particular, those bearing a coordinative ortho-substituent, could be obtained in good to excellent yields by using 0.3 mol% palladium acetate as catalyst. Features of the protocol including cost-effectiveness of diarylborinic acids, efficacy to heteroatom ortho-substituted substrates and high chemoselectivity to aryl chlorides have been clearly demonstrated in practical synthesis of fungicide Boscalid.
- Wang, Fengze,Wang, Chen,Sun, Guoping,Zou, Gang
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- Tetramethylammonium fluoride tetrahydrate-mediated transition metal-free coupling of aryl iodides with unactivated arenes in air
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Biaryls are important compounds with widespread applications in many fields. Tetramethylammonium fluoride tetrahydrate was found to promote the biaryl coupling of aryl iodides bearing electron-withdrawing substituents with unactivated arenes. The reaction takes place at temperatures between 100 and 150°C and can be applied to a wide range of aromatic and heteroaromatic rings, affording the products in moderate to high yields. The reaction does not require strong bases or expensive additives that are employed in the existing methods and can be conducted in air and moisture without any precautions.
- Nozawa-Kumada, Kanako,Nakamura, Kosuke,Kurosu, Satoshi,Iwakawa, Yuki,Denneval, Charline,Shigeno, Masanori,Kondo, Yoshinori
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p. 1042 - 1045
(2019/10/02)
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- An active catalytic system for Suzuki-Miyaura cross-coupling reactions using low levels of palladium loading
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An easily available Pd(OAc)2/(2-(anthracen-9-yl)-1H-inden-3-yl) dicyclohexylphosphine/toluene/iPrOH/water catalytic system was developed, which shows high catalytic activity in the Suzuki-Miyaura cross-coupling reactions of a diverse array of aryl and heteroaryl chlorides with Pd loadings down to 0.01 mol%.
- Yan, Meng-Qi,Yuan, Jia,Lan, Fang,Zeng, Si-Hao,Gao, Meng-Yue,Liu, Sheng-Hua,Chen, Jian,Yu, Guang-Ao
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supporting information
p. 3924 - 3929
(2017/07/10)
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- Synthesis of Biaryls by Decarboxylative Hiyama Coupling
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A trimetallic palladium/copper/silver system has been developed that allows the decarboxylative Hiyama coupling of ortho-substituted aryl carboxylates with trialkoxyarylsilanes to give the corresponding biaryls. The cross-coupling is catalyzed by a Pd/N-heterocyclic carbene complex with silver carbonate aiding its reoxidation. Copper(II) fluoride acts as decarboxylation catalyst, stoichiometric oxidant, and fluoride source. The scope of the protocol is demonstrated by 22 examples, among them aryl halides suitable for further coupling, and the synthetic utility of the products is illustrated by their conversion into carbazoles and 1H-indazoles.
- Katayev, Dmitry,Exner, Benjamin,Goossen, Lukas J.
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p. 2028 - 2032
(2015/11/24)
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- Transition-metal-free synthesis of phenanthridinones from biaryl-2-oxamic acid under radical conditions
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Na2S2O8-promoted decarboxylative cyclization of biaryl-2-oxamic acid for phenanthridinones has been developed. This work illustrates the first example of intramolecular decarboxylative amidation of unactivated arene under transition-metal-free conditions. Additionally, this approach provides an efficient and economical method to access biologically interesting phenanthridinones, an important structure motif in many natural products. (Chemical Equation Presented).
- Yuan, Ming,Chen, Li,Wang, Junwei,Chen, Shenjie,Wang, Kongchao,Xue, Yongbo,Yao, Guangmin,Luo, Zengwei,Zhang, Yonghui
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p. 346 - 349
(2015/02/19)
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- Rapid synthesis of fused N-heterocycles by transition-metal-free electrophilic amination of arene C-H bonds
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We disclose an efficient and operationally simple protocol for the preparation of fused N-heterocycles starting from readily available 2-nitrobiaryls and PhMgBr under mild conditions. More than two dozen N-heterocycles, including two bioactive natural products, have been synthesized using this method. A stepwise electrophilic aromatic cyclization mechanism was proposed by DFT calculations. Controlled fusion: A transition-metal-free, low-temperature, and regioselective intramolecular amination of aromatic C(sp2)-H bonds provides fused N-heterocycles. This reaction is operationally simple and scalable (1-10 mmol) and the scope of substrates is wide (see scheme). Density functional calculations indicate that a stepwise electrophilic aromatic cyclization mechanism may be operative.
- Gao, Hongyin,Xu, Qing-Long,Yousufuddin, Muhammed,Ess, Daniel H.,Kuerti, Laszlo
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supporting information
p. 2701 - 2705
(2014/03/21)
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- Decarboxylative cross-coupling of mesylates catalyzed by copper/palladium systems with customized imidazolyl phosphine ligands
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The activation of the inert C-O bonds in mesylates through the use of a new class of imidazolyl phosphines allows the decarboxylative coupling of aryl mesylates as well as polysubstituted alkenyl mesylates. Variation of the ligands leads to two complementary methods providing the corresponding biaryls and polysubstituted olefins in good yields. Copyright
- Song, Bingrui,Knauber, Thomas,Goo?en, Lukas J.
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p. 2954 - 2958
(2013/04/11)
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- Decarboxylative cross-coupling of aryl tosylates with aromatic carboxylate salts
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(Figure Presented) A bimetallic copper/palladium catalyst system is disclosed that enables the use of tosylates as carbon electrophiles in decarboxylative coupling reactions. A variety of aromatic carboxylate salts, regardless of their substitution pattern, have been coupled with these inexpensive and readily available electrophiles to give the corresponding biaryl compounds in good yields (see scheme).
- Goossen, Luksa J.,Rodriguez, Nuria,Lange, Paul P.,Linder, Christophe
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supporting information; experimental part
p. 1111 - 1114
(2010/04/29)
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- Pd-catalyzed decarboxylative couplings of arenecarboxylic acids with aryl iodides
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The combination of palladium chloride with BINAP shows high efficiency in the decarboxylative cross-coupling reactions of arenecarboxylic acids with aryl iodides. The reactions proceed smoothly to generate the corresponding biaryl compounds in good to excellent yields.
- Wang, Zhiyong,Ding, Qiuping,He, Xiaodan,Wu, Jie
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supporting information; experimental part
p. 4635 - 4638
(2009/10/02)
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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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- Palladium-catalyzed direct arylation of nitro-substituted aromatics with aryl halides
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(Chemical Equation Presented) Direct arylation reactions of nitrobenzenes and aryl halides occur in good yield and high ortho regioselectivity. These reactions can be performed on gram scale with as few as 3 equiv of the nitro arene relative to the aryl halide. The synthetic utility of this method is demonstrated via rapid synthesis of a Boscalid intermediate.
- Caron, Laurence,Campeau, Louis-Charles,Fagnou, Keith
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scheme or table
p. 4533 - 4536
(2009/05/07)
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- Aryl trihydroxyborates: Easily isolated discrete species convenient for direct application in coupling reactions
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A conceptually and practically simple alternative approach to the use of arylboron species as the organometallic component in cross-coupling processes is described whereby trihydroxyborate salts are isolated and directly employed. The protocol derives practical benefit from the ease and convenience of the isolation and subsequent use of the discrete borate salts, eliminates the need for additional base, and aids the use of correct reaction stoichiometry.
- Cammidge, Andrew N.,Goddard, Victoria H. M.,Gopee, Hemant,Harrison, Nicola L.,Hughes, David L.,Schubert, Christopher J.,Sutton, Benjamin M.,Watts, Gary L.,Whitehead, Andrew J.
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p. 4071 - 4074
(2007/10/03)
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- 3-Aminopyrrolidinone farnesyltransferase inhibitors: Design of macrocyclic compounds with improved pharmacokinetics and excellent cell potency
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A series of macrocyclic 3-aminopyrrolidinone farnesyltransferase inhibitors (FTIs) has been synthesized. Compared with previously described linear 3-aminopyrrolidinone FTIs such as compound 1, macrocycles such as 49 combined improved pharmacokinetic prope
- Bell, Ian M.,Gallicchio, Steven N.,Abrams, Marc,Beese, Lorena S.,Beshore, Douglas C.,Bhimnathwala, Hema,Bogusky, Michael J.,Buser, Carolyn A.,Culberson, J. Christopher,Davide, Joseph,Ellis-Hutchings, Michelle,Fernandes, Christine,Gibbs, Jackson B.,Graham, Samuel L.,Hamilton, Kelly A.,Hartman, George D.,Heimbrook, David C.,Homnick, Carl F.,Huber, Hans E.,Huff, Joel R.,Kassahun, Kelem,Koblan, Kenneth S.,Kohl, Nancy E.,Lobell, Robert B.,Lynch Jr., Joseph J.,Robinson, Ronald,Rodrigues, A. David,Taylor, Jeffrey S.,Walsh, Eileen S.,Williams, Theresa M.,Zartmant, C. Blair
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p. 2388 - 2409
(2007/10/03)
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- Inhibitors of prenyl-protein transferase
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The present invention is directed to macrocyclic compounds which inhibit prenyl-protein transferase (FTase) and the prenylation of the oncogene protein Ras. The invention is further directed to chemothera-peutic compositions containing the compounds of this invention and methods for inhibiting prenyl-protein transferase and the prenylation of the oncogene protein Ras.
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- Process for preparing nitrobiphenylene
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The invention concerns a process for preparing nitrobiphenylene of formula (I) wherein m stands for 1 or 2, R means halogen, R' or OR', R' being a C-organic group which can carry groups which are inert in the reaction conditions, n stands for 0, 1, 2 or 3 and, if n is 2 or 3, the R groups can also be different. According to the invention, a chloronitrobenzene of formula (II) is reacted in the presence of a palladium catalyst and a base in a solvent with a phenyl boric acid (IIIa), one of its alkyl esters of formula (IIIb), R meaning C1-C6 alkyl, or one of its anhydrides. The compounds (I) are suitable as initial products for biphenylamines which are in turn intermediate products for fungicidal plant-growth substances.
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