- Structural elucidation of thermolysis products of methyl N-methyl-N-nitrosoanthranilate
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Although it is common knowledge that N-nitroso compounds are thermally (and otherwise chemically) labile, little or nothing is known about the specific reactions that occur during thermal treatment of a compound possessing this functionality. Methyl N-met
- Miltojevi?, Ana B.,Radulovi?, Niko S.
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p. 53569 - 53585
(2015/06/30)
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- Efficient one-pot synthesis of dibenzopyranones via a decarboxylative cross-coupling and lactonization sequence
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A highly selective palladium bis(acetoacetonate)/copper(I) chloride [Pd(acac)2/CuCl] catalytic system for the preparation of dibenzopyranones has been developed. Tandem decarboxylative coupling and lactonization can be realized in one pot using commercially available starting materials. The reaction proceeded well for a range of different substrates. Copyright
- Luo, Jiaying,Lu, Youling,Liu, Saiwen,Liu, Jing,Deng, Guo-Jun
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supporting information; scheme or table
p. 2604 - 2608
(2011/12/01)
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- Neopentylglycolborylation of ortho -substituted aryl halides catalyzed by NiCl2-Based mixed-ligand systems
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NiCl2-based mixed-ligand systems were shown to be very effective catalysts for the neopentylglycolborylation of aryl iodides, bromides, and chlorides bearing electron-rich and electron-deficient ortho-substituents. Although NiCl2-based single-ligand catalytic systems were able to mediate neopentylglycolborylation of selected substrates, they were not as effective for all substrates, highlighting the value of the mixed-ligand concept. Optimization of the Ni(II)-catalyzed neopentylglycolborylation of 2-iodoanisole and methyl 2-iodobenzoate demonstrated that, while the role of ligand and coligand in the conversion of Ni(II) precatalyst to Ni(0) active catalyst cannot be ignored, a mixed-ligand complex is likely present throughout the catalytic cycle. In addition, protodeborylation and hydrodehalogenation were demonstrated to be the predominant side reactions of Ni(II)-catalyzed borylation of ortho-substituted aryl halides containing the electron-deficient carboxylate substituents. Ni(II) complexes in the presence of H2O and Ni(0) are responsible for the catalysis of these side reactions.
- Moldoveanu, Costel,Wilson, Daniela A.,Wilson, Christopher J.,Leowanawat, Pawaret,Resmerita, Ana-Maria,Liu, Chi,Rosen, Brad M.,Percec, Virgil
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supporting information; experimental part
p. 5438 - 5452
(2010/11/05)
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- A brand-new Pd-mediated generation of benzyne and its [2+2+2] cycloaddition: δ-carbon elimination and concomitant decarboxylation
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We found a brand-new method for the generation of aryne from methyl 2-bromobenzoates via the Pd-mediated concomitant δ-carbon elimination and decarboxylation. The generated arynes underwent Pd-mediated [2+2+2] cycloaddition to give triphenylenes.
- Kim, Hoo Sook,Gowrisankar, Saravanan,Kim, Eun Sun,Kim, Jae Nyoung
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scheme or table
p. 6569 - 6572
(2009/04/05)
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- Phosphinates as new electrophilic partners for cross-coupling reactions
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The use of enol phosphinates as electrophiles for cross-coupling reactions has been explored. Both boronic acids (Suzuki-Miyaura reaction) and stannanes (Stille reaction) couple efficiently with lactam derived phosphinates. The 2008 Royal Society of Chemi
- Guo, Jun,Harling, John D.,Steel, Patrick G.,Woods, Tom M.
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supporting information; experimental part
p. 4053 - 4058
(2009/06/28)
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- Copper(I)-catalysed homo-coupling of aryldiazonium salts: synthesis of symmetrical biaryls
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Copper(I) triflate acts as an efficient stoichiometric reagent for the homo-coupling of aryldiazonium salts bearing electron-withdrawing group(s), to yield symmetrical biaryls in acetonitrile under mild reaction conditions. Aryldiazonium salts bearing electron-donating groups undergo the reaction by using catalytic amounts of a copper complex prepared in situ from copper(II) triflate and 2,2′-bipyridine with metallic copper as an ultimate reductant.
- Cepanec, Ivica,Litvi?, Mladen,Udikovi?, Josipa,Pogoreli?, Ivan,Lovri?, Marija
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p. 5614 - 5621
(2007/12/29)
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- Synthesis of quinolines, 2-quinolones, phenanthridines, and 6(5H)-phenanthridinones via palladium[0]-mediated Ullmann cross-coupling of 1-bromo-2-nitroarenes with β-halo-enals, -enones, or -esters
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Palladium[0]-mediated Ullmann cross-coupling of 1-bromo-2-nitrobenzene (1 R = H) and its derivatives with a range of β-halo-enals, -enones, or -esters readily affords the corresponding β-aryl derivatives, which are converted into the corresponding quinolines, 2-quinolones, phenanthridines, or 6(5H)-phenanthridinones on reaction with dihydrogen in the presence of Pd on C or with TiCl3 in aqueous acetone.
- Banwell, Martin G.,Lupton, David W.,Ma, Xinghua,Renner, Jens,Sydnes, Magne O.
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p. 2741 - 2744
(2007/10/03)
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- Homocoupling of aryl iodides and bromides promoted by sulfur-containing palladacycles
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Sulfur-containing palladacycles, in particular those derived from the orthometalation of benzylthioethers, effectively promote the homocoupling of aryl iodides and bromides, under relatively mild reaction conditions to furnish symmetrical biphenyls in good yields.
- Silveira, Priscila B.,Lando, Vanusa R.,Dupont, Jairton,Monteiro, Adriano L.
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p. 2327 - 2329
(2007/10/03)
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- The Oxidative Coupling of Methyl Benzoate
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The reaction of methyl benzoate (MBA) with pressurized (50 atm) artificial air (50 mol% O2-N2 mixture) at 150-200°C over a soluble palladium catalyst [PdLL2′] (L=phen, bipy, dppe; L′=OAc, TFA) afforded isomeric dimethyl bibenzoic acid esters (DMBBA). Different factors affect the reactivity and regioselectivity of the process. The reactivity is enhanced by trifluoromethanesulfonic acid, arguably by activating the C-H bond of the aromatic ring by its protonation. The increase of temperature not only increases the reaction rate (EA=5.5 kcal/mol) but also favors a formation of an ortho-coupled product. Ligands with strong trans influence (L=phen, bipy, or dppe) direct the oxidative coupling away from 2,X′-isomers (X=2, 3, or 4). Overall, electronic properties of a palladium catalyst are more important than steric restriction of the same catalyst for altering the activity and regioselectivity for MBA coupling.
- Iretskii,Sherman,White,Kenvin,Schiraldi
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- The Hurtley reaction III. A reactivity study of copper(I) 2-halobenzoates either as pure reagents, or under Hurtley reaction conditions, and as a part of mixed (benzoato)(mesityl)copper(I) clusters
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The reactivity of pure isolated copper(I) 2-halobenzoates has been studied at 20 and 80 deg C either with or without oxidizing agents (O2 and CuBr2).Furthermore, these complexes have been reacted at 80 deg C either alone or in combination with sodium acet
- Aalten, Henk L.,Koten, Gerard van,Vrieze, Kees,Kerk-van Hoof, Anca van der
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- Abnormal Products from the Exhaustive Ozone Oxidation of Phenanthrene in HCl/Methanol
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Exhaustive ozone treatment of phenanthrene (6) in HCl/methanol afforded unsubstituted (10a) and chloro-substituted 6H-dibenzopyran-6-ones (10b - d) in addition to the expected dimethyl 2,2'-biphenyldicarboxylate (9c).
- Neumeister, Joachim,Griesbaum, Karl
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p. 1640 - 1642
(2007/10/02)
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- Unsymmetrical Ketone Synthesis via Palladium Catalyzed Carbonylation of Organic Halides
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Aryl alkyl (or benzyl) ketones are selectively prepared by the reaction of aryl iodides and alkyl iodides (or benzyl chlorides) in the presence of a stoichiometric amount of zinc-copper couple and a catalytic amount of palladium(O) complex under an atmospheric pressure of carbon monoxide.
- Tamaru, Yoshinao,Ochiai, Hirofumi,Yamada, Yoshimi,Yoshida, Zen-ichi
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p. 3869 - 3872
(2007/10/02)
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- Ozonolysis of Symmetrically 1,2-Disubstituted Ethylenes in HCl/Methanol Solutions: Acid Catalyzed Reactions of Primary Cleavage Products
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The ozonolysis of olefins in 1 M anhydrous solutions of hydrogen chloride in methanol at /= 0 deg C was investigated.Upon warm-up of the ozonolysis products, the peroxidic primary fragmentation products were converted into non peroxidic end-products by HCl-catalyzed reactions.Cyclopentene (1a) and cyclohexene (1b), e.g., afforded mixtures of the corresponding α,ω-dialdehydebis(dimethyl acetals) (8), dimethyl α,ω-dicarboxylates (9), and methyl ω-aldehyde dimethyl acetal carboxylates (10).Norbornene (1c) gave a mixture of the correspondingly substituted 1,3-cyclopentane compounds (8c - 10c), phenanthrene (22) gave a mixture of methyl 2'-formyl-2-biphenylcarboxylate (24a), 2,2'-biphenyldicarbaldehyde (24b), and dimethyl 2,2'-biphenyldicarboxylate (24c).A reaction scheme was advanced for the rationalization of the types and the distribution of the products.It was partly substantiated by model reactions.
- Griesbaum, Karl,Neumeister, Joachim
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p. 2697 - 2706
(2007/10/02)
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