- Photoinduced Cross-Coupling of Aryl Iodides with Alkenes
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A protocol for photoinduced cross-coupling of aryl iodides having polar π-functional groups or elongated π-conjugation with alkenes has been developed. The radical cascade mechanism involving generation of aryl radicals via C-I bond homolysis of photoexcited aryl iodides and their subsequent addition to alkenes is proposed. The method enables iodide-selective cross-coupling over other halogen leaving groups with functional group compatibility on both arene and alkene motifs.
- Liu, Yuliang,Li, Haoyu,Chiba, Shunsuke
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p. 427 - 432
(2021/01/26)
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- PtO2/PTSA system catalyzed regioselective hydration of internal arylalkynes bearing electron withdrawing groups
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A highly efficient PtO2/PTSA catalyst system for the hydration of a wide array of alkynes was developed. This method proved to be compatible with a large range of functional groups and the ketone products were obtained in high yields. The scope of this methodology was also extended to the synthesis of 3-Aryl-isochromenones,-indoles and-benzofurans.
- Lin, Hsin-Ping,Ibrahim, Nada,Provot, Olivier,Alami, Mouad,Hamze, Abdallah
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p. 11536 - 11542
(2018/04/05)
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- A family of low molecular-weight, organic catalysts for reductive C-C bond formation
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Hydrazines form a new family of low molecular-weight reducing agents for diazonium salts. Using only small amounts of hydrazine catalyst, the coupling of diazonium salts to a variety of reactive partners has been achieved, without the requirement for either metal adjuvants or irradiation with visible or ultraviolet light. The generality of the concept proposed herein as well as its advantages in the preparative scale is outlined and discussed.
- Shaaban, Saad,Jolit, Ana?s,Petkova, Desislava,Maulide, Nuno
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p. 13902 - 13905
(2015/09/15)
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- Copper(II)triflate promoted highly chemoselective rearrangement of chalcone epoxides to β-keto aldehydes
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Highly chemoselective rearrangement of chalcone epoxides to β-keto aldehydes using catalytic amount of Cu(OTf)2 (1 mol%) is presented. Copper(II)triflate is a relatively cheap, inexpensive and commercially available catalyst. In this rearrangement selective migration of the acyl group takes place. The presence of an electron donating group on either of the phenyl rings favors the reaction. However, the presence of an electron withdrawing CN group leads to the corresponding β-keto aldehyde, along with an aryl ketone which is obtained through deformylation of the primary product.
- Jadhav, Balaso G.,Vaidya, Ashish A.,Samant, Shriniwas D.
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- An expedient route to heterocycles through α-arylation of ketones and arylamides by microwave induced thermal SRN1 reactions
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Microwave irradiation promotes a quick aromatic nucleophilic substitution by a thermally induced electron transfer process to form new C-C bonds by the coupling of aryl radicals and enolate nucleophiles. Diverse 2-aryl-1- phenylethanones can be prepared by the direct α-arylation of acetophenone with different haloarenes. The ketone enolate anion is generated by deprotonation with tBuOK in DMSO and the reaction is carried out in a closed microwave vessel at 70-100°C for 10 min. This simple procedure also allows the synthesis of deoxybenzoin and indole heterocycle derivatives by inter- or intra-molecular ring closure reactions, with moderate to excellent substitution yields. This journal is the Partner Organisations 2014.
- Soria-Castro, Silvia M.,Caminos, Daniel A.,Penenory, Alicia B.
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p. 17490 - 17497
(2014/05/06)
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- Palladium-catalyzed carbonylative negishi-type coupling of aryl iodides with benzyl chlorides
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Do the competition: The synthesis of 1,2-diarylethanones has been accomplished using the palladium-catalyzed coupling of aryl iodides and CO/benzyl chlorides or benzoyl chlorides. These reactions proceed smoothly in the presence of zinc powder to afford the products in moderate to excellent yields.
- Wu, Xiao-Feng,Schranck, Johannes,Neumann, Helfried,Beller, Matthias
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supporting information; experimental part
p. 40 - 44
(2012/03/11)
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- Regioselective synthesis of 2,3,4- or 2,3,5-trisubstituted pyrroles via [3,3] or [1,3] rearrangements of O-vinyl oximes
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The regioselective synthesis of 2,3,4- or 2,3,5-trisubstituted pyrroles has been achieved via [3,3] and [1,3] sigmatropic rearrangements of O-vinyl oximes, respectively. Iridium-catalyzed isomerization of easily prepared O-allyl oximes enables rapid access to O-vinyl oximes. The regioselectivity of pyrrole formation can be controlled by either the identity of the α-substituent or through the addition of an amine base. When enolization is favored, a [3,3] rearrangement followed by a Paal-Knorr cyclization provides a 2,3,4-trisubstituted pyrrole; when enolization is disfavored, a [1,3] rearrangement occurs prior to enolization to produce a 2,3,5-trisubstituted pyrrole after cyclization. Optimization and scope of the O-allyl oxime isomerization and subsequent pyrrole formation are discussed and mechanistic pathways are proposed. Conditions are provided for selecting either the [3,3] rearrangement or the [1,3] rearrangement product with β-ester O-allyl oxime substrates.
- Wang, Heng-Yen,Mueller, Daniel S.,Sachwani, Rachna M.,Kapadia, Rachel,Londino, Hannah N.,Anderson, Laura L.
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supporting information; experimental part
p. 3203 - 3221
(2011/06/24)
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- Palladium-catalyzed carbonylative suzuki coupling of benzyl halides with potassium aryltrifluoroborates in aqueous media
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A general palladium-catalyzed carbonylative cross-coupling reaction of benzyl chlorides with potassium aryltrifluoroborates in water has been developed. Applying this improved methodology 16 different 1,2-diarylethanones have been synthesized in 40-89% yield. Copyright
- Wu, Xiao-Feng,Neumann, Helfried,Beller, Matthias
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experimental part
p. 788 - 792
(2011/05/15)
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- NOVEL DIHYDROPYRIMIDIN-2(1H)-ONE COMPOUNDS AS S-NITROSOGLUTATHIONE REDUCTASE INHIBITORS
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The present invention is directed to novel dihydropyrimidin-2(1H)-one compounds useful as S-nitrosoglutathione reductase (GSNOR) inhibitors, pharmaceutical compositions comprising such compounds, and methods of making and using the same.
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Page/Page column 141
(2011/04/24)
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- Heck reactions of α- or β-substituted enol ethers with aryl bromides catalysed by a tetraphosphane/palladium complex - Direct access to acetophenone or 1-arylpropanone derivatives
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cis,cis,cis-1,2,3,4-Tetrakis(diphenylphosphanylmethyl)cyclopentane/ [PdCl(C3H5)]2 efficiently catalyses the Heck reaction of α- and β-substituted enol ethers with aryl bromides. The arylation of 1-phenyl-1-(trimethylsilyloxy) ethylene led directly to the 2-aryl-1-phenylethanones. Similar reaction rates were observed with electron-rich, electron-deficient or sterically congested aryl bromides. Heck reaction with benzyl isopropenyl ether gave a mixture of isomers. However, this mixture gave selectively the 1-arylpropanones after hydrolysis. Employing β-methoxystyrene, 3-ethoxyacrylonitrile or methyl 3-methoxyacrylate, the regioselective α-arylation of these enol ethers was observed in all cases, but mixtures of (Z) and (E) isomers were generally obtained, which in many cases yielded a single ketone product after acid treatment. The stereoselectivity of this reaction depends on steric and electronic factors, and better stereoselectivities in favour of (Z) isomers were observed with electron-rich or sterically congested aryl bromides. Higher yields were obtained for this reaction with electron-rich or sterically congested aryl bromides than with electron-poor aryl bromides. These observations suggest that the rate-limiting step of the catalytic cycle is not the oxidative addition of the aryl bromide to the palladium complex with these substituted enol ethers. Wiley-VCH Verlag GmbH & Co. KGaA, 2007.
- Battace, Ahmed,Feuerstein, Marie,Lemhadri, Mhamed,Zair, Touriya,Doucet, Henri,Santelli, Maurice
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p. 3122 - 3132
(2008/02/08)
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- Pd-catalyzed α-arylation of trimethylsilyl enol ethers with aryl bromides and chlorides: A synergistic effect of two metal fluorides as additives
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(Chemical Equation Presented) The long-sought-after palladium-catalyzed coupling of silyl enol ethers, both cyclic and acyclic, with a wide range of aryl bromides and chlorides to form α-aryl ketones is realized. The key to effective activation of the silicon enolate was the use of two metal fluoride additives, which operate in a synergistic fashion.
- Su, Weiping,Raders, Steven,Verkade, John G.,Liao, Xuebin,Hartwig, John F.
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p. 5852 - 5855
(2007/10/03)
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- Highly regioselective, sequential, and multiple palladium-catalyzed arylations of vinyl ethers carrying a coordinating auxiliary: An example of a heck triarylation process
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This article describes the development of new auxiliary-accelerated Heck multiarylations by intramolecular presentation of the oxidative addition complex. The introduction of a specific, palladium-coordinating dimethylamino group allows for the desired chelation-accelerated and chelation-controlled tri- and diarylation reactions. We report (a) the first example of a Heck triarylation process, (b) highly selective palladium-catalyzed diarylations of alkyl vinyl ethers, and (c) a very rapid two-phase protocol for the microwave-assisted hydrolysis of amino-substituted, arylated vinyl ethers constituting an entry to diarylated ethanals and substituted desoxybenzoins. X-ray structures and product patterns support the suggested substrate-controlled Heck reaction pathway. The catalyst-directing alkyl dimethylamino functionality was rapidly (1-2 min) and efficiently released by microwave hydrolysis after Heck multiarylation reactions. The liberated aromatic carbonyl compounds were thereafter isolated and fully characterized.
- Nilsson,Larhed,Hallberg
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p. 8217 - 8225
(2007/10/03)
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- N-(heterocycle)alkyl)-1H-pyrazole-1-alkanamides as antiarrhythmic agents, compositions and use
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N-[(heterocycle)alkyl]-3,4 (or 4,5)-diaryl-1H-pyrazole-1-acetamides and pyrazole-1-propanamides, useful for treating cardiac arrhythmias in mammals, are prepared by reacting a lower-alkyl ester of pyrazole-1-acetic or propanoic acid with an appropriate (heterocycle-alkyl) amine or by reacting a pyrazole-1-acetic or propanoic acid with an appropriate (heterocycle-alkyl)amine.
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- 1H-pyrazole-1-alkanamides, antiarrhythmic compositions and use
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N-[(disubstituted amino)alkyl]-3,4 (or 4,5)-diaryl-1H-pyrazole-1-acetamides and pyrazole-1-propanamides, useful for treating cardiac arrhythmias in mammals, are prepared by reacting a lower-alkyl ester of pyrazole-1-acetic or propanoic acid with an appropriate diamine or by reacting a lower-alkyl ester of a pyrazole-1-acetic or propanoic acid with an ω-aminoalkanol, followed by activation of the alcohol and displacement by an appropriate amine.
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- A Facile One-Pot Synthesis of Vicinal Di- and Triketones from α-Methylene Ketones by NBS-DMSO Oxidation
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The reaction of 1,2-diarylethanones (1a-u) with N-bromosuccinimide in anhydrous dimethyl sulphoxide afforded diarylethanediones (2a-u) in excellent yields.Under similar conditions, 1-phenyl-2-butanone (3) gave 1-phenyl-1,2-butanedione (4) in fair yield in addition to a small amount of 1-phenyl-3-methylthio-1,2-butanedione (5) and 1-phenyl-1-methylthio-2-butanone (6). 4-Phenyl-2-butanone (7), 1,3-diphenyl-2-propanone (9), and 1,3-diphenyl-1,3-propanedione (10) gave the corresponding triketones monohydrate (8) and (11). 1-Indanone (12), 2-indanone (13), and 1,3-indandione (14) gave ninhydrin (15) in good yields.In the case of 3-phenyl-1-indanone (16), 3-phenyl-2-bromo-1-indanone (17), 3-phenyl-2-bromo-1-indenone (18) and 3-phenyl-1-indenone (19) were obtained. 1-Phenyl-1-propanone (20) and 1-phenyl-1-butanone (22) gave the corresponding α-(methylthio)ketones (21) and (22). 1,3,3-Triphenylpropanone (24a) and 1-phenyl-3-methyl-1-butanone (24b) yielded only the corresponding α-bromoketones (25a,b) in good yields.These α-bromoketones, however, afforded the corresponding α-diketones (26a,b) in moderate yields when α-bromoketones reacted with dimethyl sulphoxide in the presence of AgBF4.
- Tatsugi, Jiro,Izawa, Yasuji
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p. 2747 - 2763
(2007/10/02)
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- Direct Preparation of Organocadmium Compounds from Highly Reactive Cadmium Metal Powders
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Highly reactive cadmium metal powders and a cadmium-lithium alloy were prepared and were used to prepare organocadmium reagents directly from organic halides.
- Burkhardt, Elizabeth R.,Rieke, Reuben D.
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p. 416 - 417
(2007/10/02)
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- phosphonium Salts, 3. Reductive C-Acylation of Aromatic Aldehydes
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The phosphonium salts 5 are synthesized from aldehydes 1, arenecarbonyl chlorides 2 and triphenylphosphane (4), and can then be deprotonated to 7. 7 react as acyl anion equivalents with aromatic aldehydes 9 forming enol esters 10, which are transformed to alkanones 11.The new aldehyde 9->alkanone 11-transformation is characterised as a reductive C-acylation of aromatic aldehydes.
- Anders, Ernst,Gassner, Thomas
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p. 1034 - 1038
(2007/10/02)
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- ARYL REARRANGEMENT ON THE PHOTOLYSIS OF 2-ARYL-2-ETHOXY-2-PHENYLETHYL CABALOXIME.
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The photolysis of 2-aryl-2-ethoxy-2-phenylethyl cobaloxime followed by hydrolysis gave two kinds of substituted 1,2-diphenylethanones arising via phenyl or substituted-phenyl migration. The substituent effect on the aryl rearrangement is similar to that on the reported neophyl rearrangement, and the rearrangement takes place by a radical mechanism without the deep involvement of cobaloxine(II).
- Tada,Inoue,Okabe
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p. 1420 - 1423
(2007/10/02)
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