- Development of Versatile Sulfone Electrophiles for Suzuki-Miyaura Cross-Coupling Reactions
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The development of fluorinated sulfone derivatives as versatile electrophiles for Suzuki-Miyaura cross-coupling reactions is described. Introducing electron-withdrawing groups on the aryl ring of the sulfone facilitates the Pd-catalyzed activation of C-SO2 bonds. Cross-coupling reactions with fluorinated sulfone electrophiles are reported, leading to a variety of multiply arylated products in good yields. The reactivity of this unusual electrophile is benchmarked versus common electrophiles and its use in iterative cross-couplings for concise synthesis of biologically active molecules is described.
- Nambo, Masakazu,Keske, Eric C.,Rygus, Jason P. G.,Yim, Jacky C.-H.,Crudden, Cathleen M.
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p. 1108 - 1112
(2017/08/09)
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- Functional Ionic Liquids as Efficient and Recyclable Catalysts for the Methylation of Formaldehyde with Aromatics
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Abstract: Methylation of formaldehyde with various aromatics under functional ionic liquids catalysis has been developed. Among the ionic liquids investigated, triphenyl-(4-sulfobutyl)-phosphonium triflate ([TTPBs][CF3SO3]) showed high activity and afforded excellent yields of diarylmethane derivatives. A mechanism for the catalytic performance of [TTPBs][CF3SO3] is proposed. Besides, the catalyst can simply be separated from the reaction mixture by centrifugation and be recycled ten times without noticeable loss of activity. Graphical Abstract: Diarylmethane derivatives were successfully synthesized from the methylation of formaldehyde with aromatics using efficient and recyclable functional ionic liquids as catalysts, excellent yields and selectivities were obtained under solvent free conditions. The catalyst was reused at least ten consecutive recycles without noticeable loss in its catalytic activity. Meanwhile, the usability of catalyst was explored.[Figure not available: see fulltext.]
- Song, Heyuan,Jin, Fuxiang,Jin, Ronghua,Kang, Meirong,Li, Zhen,Chen, Jing
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p. 1264 - 1272
(2016/07/06)
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- A tubular europium-organic framework exhibiting selective sensing of Fe3+ and Al3+ over mixed metal ions
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A luminescent europium-organic framework with tubular channels based on the H4BTMIPA ligand (H4BTMIPA = 5,5′-methylenebis(2,4, 6-trimethylisophthalic acid)) was assembled and characterized. The [H 2N(CH3)2]+ ions as counterions are located in the channels. The cation exchange between [H2N(CH 3)2]+ and metal ions resulted in complex 1 that can selectively sense Fe3+ and Al3+ ions through fluorescence quenching and enhancement, respectively.
- Sun, Daofeng,Chen, Zhen,Sun, Yanwen,Zhang, Liangliang,Sun, Di,Liu, Fuling,Meng, Qingguo,Wang, Rongming
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supporting information
p. 11557 - 11559
(2013/12/04)
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- Phase transfer catalyst supported, room-temperature biphasic synthesis: A facile approach to the synthesis of coordination polymers
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A facile approach, named phase transfer catalyst supported, room temperature biphasic synthesis, has been developed to synthesize a new type of coordination polymers. Compared to the traditional biphasic solvothermal synthesis that was run at high temperature (100-200 °C), the new approach introduced here can be operated under a mild condition (room temperature) with the support of phase transfer catalyst. With the application of this new approach, two copper coordination complexes with 1D metal-organic nanotube and 1D coordination polymer containing large water clusters have been successfully synthesized and characterized. Furthermore, the synthetic approach presented here can be extended to synthesize other coordination polymers, including porous lanthanide-organic frameworks.
- Zhao, Xiao-Liang,Sun, Di,Hu, Tuo-Ping,Yuan, Shuai,Gu, Li-Chuan,Cong, Heng-Jiang,He, Hai-Yan,Sun, Dao-Feng
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supporting information; experimental part
p. 4320 - 4323
(2012/06/16)
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- Sulfonylation of aromatic compounds with methyl p-toluenesulfonate as a sulfonylating precursor
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We have developed Friedel-Crafts (FC) sulfonylation of aromatic compounds with methyl p-toluenesulfonate as a sulfonylating precursor. In this procedure, methyl p-toluenesulfonate was treated and activated with pyridine to produce N-methylpyridinium p-toluenesulfonate as a sulfonylation reagent. Reactivity of this salt for the sulfonylation of mesitylene was investigated in the presence of three different promoters, such as triflic anhydride, dimethylsulfide ditriflate, and triphenylphosphine ditriflate (TPPD). All of the promoters show chemoselectivity and among them, TPPD presents a chemoselectivity in FC sulfonylation. Iranian Chemical Society 2012.
- Khodaei,Nazari
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p. 507 - 512
(2013/02/22)
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- o-Benzenedisulfonimide as a reusable Bronsted acid catalyst for Ritter-type reactions
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Reactions between various benzyl alcohols or tert-butyl alcohol and nitriles were carried out in the presence of catalytic amounts (usually 10-20 mol-%) of o-benzenedisulfonimide as a Bronsted acid catalyst; the reaction conditions were mild and the yields of amides were good. The catalyst was easily recovered and purified, ready to be used in further reactions, with economic and ecological advantages. Wiley-VCH Verlag GmbH & Co. KGaA, 2009.
- Barbero, Margherita,Bazzi, Stefano,Cadamuro, Silvano,Dughera, Stefano
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experimental part
p. 430 - 436
(2009/07/19)
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- Non-coplanar aromatic carboxylic acids: Unusual conformation-dependent self-assembly and pseudopolymorphism of di(3-carboxymesityl)methane
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The dicarboxylic acids 3 and 4, i.e., di(3-carboxy-2,4,6-trimethylphenyl)methane and di(3-carboxyphenyl)methane, are created by a methylene tethering of mesitoic acid and benzoic acid, respectively. These diacids may explore two low energy conformations, viz., syn and anti. Whereas the syn-diacid 3 is found to undergo self-assembly in the solid state via a very rare tetrameric motif, the anti-diacid 3 is found to exhibit pseudopolymorphism with guest molecules such as DMSO and PhOH-H2O. The unusual patterns of assembly and the occurrence of pseudopolymorphism for the syn and anti conformers, respectively, appear to emanate from an unique structural feature that emerges as a consequence of tethering. It appears that the molecules that contain strongly interacting functional groups in non-coplanar aryl rings will suffer from packing problems, which manifests itself in a new mode of packing and the phenomenon of pseudopolymorphism.
- Moorthy, Jarugu Narasimha,Natarajan, Palani
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scheme or table
p. 139 - 148
(2009/02/03)
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- Pentafluorophenylation of aromatic compounds with 4,5,6,7,8-pentafluoro-6- nitro-1-oxaspiro[2.5]octa-4,7-diene
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4,5,6,7,8-Pentafluoro-6-nitro-1-oxaspiro[2.5]octa-4,7-diene reacts with arenes in the presence of AlCl3 to give pentafluorobiphenyls.
- Kovtonyuk,Kobrina,Haufe
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experimental part
p. 1686 - 1688
(2011/04/23)
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- An efficient synthesis of diarylmethanes via InCl3*4H2O-catalyzed dehydration of electron-rich arenes with trioxane
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A facile, efficient and environmentally benign procedure for the synthesis of diarylmethanes via the reaction of arenes with trioxane catalyzed by InCl3*4H2O was developed. The reactions of aromatic compounds bearing electron-donating group proceeded smoothly affording the corresponding diarylmethanes in good to excellent yields.
- Sun, Hong-Bin,Hua, Ruimao,Yin, Yingwu
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p. 2291 - 2294
(2007/10/03)
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- Uncatalyzed Friedel-Crafts alkylation of aromatic compounds through reactive benzyl cations generated from N-sulfamoylcarbamates
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(Matrix presented) A new method for the generation of highly reactive benzyl cations by thermal decomposition of aryl-benzyl-sulfamoylcarbamates, obtained in a one-pot reaction from chlorosulfonyl isocyanate, is described. The generated cations alkylate aromatic compounds efficiently in the absence of catalysts.
- Sefkow, Michael,Buchs, Jens
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p. 193 - 196
(2007/10/03)
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- Spectroscopic and product studies of the effect of para substituents on the reactivity of triplet bis(2,6-dimethylphenyl)carbenes
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A series of diazobis(2,6-dimethylphenyl)methanes (1) bearing eight symmetrical para di-substituents have been prepared and photolyzed to generate the corresponding carbenes (2). Product analysis studies showed that carbenes (2) decay mainly either by dimerization to form tetra(aryl)ethylene (3) or by attack at an o-methyl group to afford 1,2-dihydrobenzocyclobutenes (4) by way of o-quinodimethanes (6) in solution. The zero-field splitting parameters, D and E, were measured in matrices of different viscosities and are analyzed in terms of a sigma-dot (σ.) scale of spin-delocalization substituent constants. Fairly good correlation with σ. was found for the D values of 32 in its minimum energy geometry. Stabilities of 32 were estimated either by measuring the temperature at which the triplet carbene signals disappeared upon thawing the matrix or by analyzing the decay kinetics of 32 in a degassed solution at room temperature. They are examined in terms of the D values in matrix at low temperature and in terms of product distributions in solution at room temperature.
- Hu, Yingmo,Ishikawa, Yui,Hirai, Katsuyuki,Tomioka, Hideo
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p. 2207 - 2218
(2007/10/03)
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- Resolution and Enantiomerization Barrier of Tetramesitylethylene
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The 1H NMR spectrum of tetramesitylethylene (2) was analyzed, and the signals were assigned by means of a 2D NOESY spectrum.Attempts to observe anisochrony of the enantiotopic groups of a racemic mixture of 2 in a chiral solvent by 1H NMR were unsuccesful.Molecular mechanics and MNDO calculations satisfactorily reproduce the ground-state conformation.The calculated barrier for the enantiomerization process is 21.8 (MM2) and 28.2 (MNDO) kcal mol-1. 2 was chromatographically resolved on a (+)-poly(triphenylmethyl)methacrylate (PTrMA) column.Its specific rotation is 25 = -12100 deg at 365 nm and -2300 deg at 589 nm (D line).The activation parameters for the enantiomerization of 2 in perhydrofluorene are ΔG = ΔH = 39.6 kcal mol-1 and ΔS = 0 cal mol-1 K-1.The barrier for 2 is the highest determined experimentally for a correlated rotation.
- Gur, Erez,Kaida, Yuriko,Okamoto, Yoshio,Biali, Silvio E.,Rappoport, Zvi
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p. 3689 - 3693
(2007/10/02)
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- Singlet and Triplet Dimesitylcarbene
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The triplet states of essentially all diarylcarbenes react with substrates such as methanol or their parent diazo compounds both of which are thought to be specific quenchers for the singlet state.To rationalize these results, investigators have proposed that the singlet and triplet states of these carbenes are linked by efficient equilibria.In this kinetic study we have found that the singlet and triplet states of dimesitylcarbene exhibit quite distinct chemistries.The singlet state alone reacts with methanol, 1-propanol, and 1,3-cyclohexadiene, while the triplet carbene dimerizes to give olefin or, for example, reacts with oxygen.No evidence was found for reaction of the triplet carbene via the singlet manifold.Arguments are presented to explain the enhanced free energy difference between the spin states of this carbene and the relative persistence if its triplet.
- Nazran, A. S.,Griller, D.
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p. 543 - 547
(2007/10/02)
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- ATTEMPTED SYNTHESIS OF TRIMESITYLPHOSPHAETHENE; OBSERVATIONS RELATED TO THE MECHANISM OF ACID CATALYZED NUCLEOPHILIC SUBSTITUTIONS AT PHOSPHORUS (III)
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Trimesitylphosphaethene (MesP=CMes2, 1f) is of interest as a sterically protected and presumably very stable phosphaalkene.Its synthesis was attempted along three different routes.The first two routes were modelled after the well-documented syntheses by phosphaalkenes by base catalyzed elimination of hydrogen chloride from MesPClCHMes2 (3).In the first approach, 3 could not be obtained from the precursor MesP(NEt2)CHMes2 (4) by treatment with hydrogen chloride.Instead, the phosphonium salt +Cl- (2) was formed; (2) is of interest as a "frozen" intermediate in the acid catalyzed nucleophilic substitution at phosphorus(III).The mechanistic implications of its formation and the reasons for its lack of reactivity are discussed.In the second approach, 3 was obtained from the reaction of MesPCl2 (8) with α-potassiodimesitylmethane.However, several attempts to eliminate hydrogen chloride from 3 were unsuccessful.Similarly, the third route, aimed at the preparation of ClP=CMes2 (9) from Cl2PCHMes2 (10) was thwarted because hydrogen chloride could not be eliminated from 10.The unusual behavior of 2, 3, and 10 can be explained by steric hindrance in these extremely crowded molecules.
- Knaap, Theodorus A. van der,Bickelhaupt, Friedrich
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p. 227 - 236
(2007/10/02)
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- Methylene coupling of aromatics
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Methylene coupled aromatic compounds are prepared by contacting an aromatic reactant having a reactive hydrogen with chloromethyl methyl carbonate at a temperature from about 25° C. to about 250° C. in the presence of a catalytic amount of a Lewis acid.
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- A SIMPLE AND INEXPENSIVE PROCEDURE FOR CHLOROMETHYLATION OF CERTAIN AROMATIC COMPOUNDS
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Reaction of a range of aromatic compounds with methoxyacetyl chloride and aluminium chloride in either nitromethane or carbon disulphide results in chloromethylation in good to excellent yield.
- McKillop, Alexander,Madjdabadi, Fereidon Abbasi,Long, David A.
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p. 1933 - 1936
(2007/10/02)
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- Reductive Coupling of Aromatic Ketones by Low-valent Titanium Salts
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Reaction of sterically congested aromatic ketones with the McMurry reagent (4TiCl3, LiAlH4) in tetrahydrofuran yields is not only the olefins (E- and Z-isomers), but also the corresponding ethanes and some other products.We have studied the minor or non-normal products of this reaction.
- Bottino, Francesco,Finocchiaro, Paolo,Libertini, Emanuela,Reale, Antonino,Recca, Antonino
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- Use of Tellurium(IV) and Tellurium(VI) as Oxidants in Organic Synthesis
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The oxidizing properties of TeO2, Te(OH)6, and TeO3 in acetic acid solution containing LiBr have been explored.It was found that certain aromatic compounds were acetoxymethylated by the action of TeO2 or, when especially activated, converted into diarylmethane derivatives.Te(OH)6 and TeO3, in contrast, mainly effected side-chain acetoxylation, as was also the case with SeO2.In the acetoxymethylation reaction TeO2 apparently slowly oxidized the solvent, HOAc, to a reactive species of some kind, e.g., acetoxycarbene, which attacked the aromatic compound.In the side-chain acetoxylations, Te(VI) oxidized bromide ions to Br2, which caused benzylic bromination.The solvolysis of benzylic bromides to acetates was significantly enhanced by the presence of Te(IV) species.Both TeO2 and TeO3 effected more conventional oxidations like the transformation of deoxybenzil to benzil.Benzoin acetate is a probable intermediate in this oxidation.
- Bergman, Jan,Engman, Lars
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p. 5191 - 5196
(2007/10/02)
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- EVIDENCE FOR SINGLE ELECTRON TRANSFER IN THE REDUCTION OF ALCOHOLS WITH LITHIUM ALUMINIUM HYDRIDE
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EPR evidence supporting a single electron transfer mechanism in the reduction of secondary and tertiary alcohols to hydrocarbons with LiAlH4 is presented.
- Ashby, E. C.,Goel, A. B.
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p. 1879 - 1880
(2007/10/02)
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- Evidence of Single Electron Transfer in the Reduction of Various OrganicSubstrates by Lithium Tetrakis(N-dihydropyridyl)aluminate
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Aromatic ketones, polynuclear hydrocarbons, and alkyl halides with LiAl(PyH)4 by a single electron transfer process.
- Ashby, E.C.,Goel, A.B.
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p. 3934 - 3936
(2007/10/02)
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- Electrophilic Methylthiomethylation of Enol Ethers and Activated Aromatic Compounds. Application of the Former Reaction to the Synthesis of the Macrocycle, 3,3,7,7,11,11,15,15-Octamethyl-1,9-dithia-5,13-diazacyclohexadecane
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Enol ethers of dialkylacetaldehydes, either as such, or generated in situ from the corresponding acetals, undergo ready methylthiomethylation when heated with dimethyl sulphoxide-acetic anhydride (or methylthiomethyl acetate) in the presence of boron trifluoride-diethyl ether.These same reagent combinations can be used to methylthiomethylate certain activated aromatic compounds.The synthetic utility of the former reaction is demonstrated in the synthesis of 2,2,6,6-dimethyl-4-thiaheptanedial (4) which has been converted into 3,3,7,7,11,11,15,15-octamethyl-1,9-dithia-5,13-diazacyclohexadecane (7).
- McCrindle, Robert,McAlees, Alan J.,Stephenson, Donald K.
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p. 3070 - 3073
(2007/10/02)
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- Sterically Hindered Olefins, VIII. Reaction of 1-Indanones with Low-valent Titanium Compounds. Steric Influence of Methyl Substituents in 1-(1-Indanyliden)indanes and 9-(9-Fluorenylidene)fluorenes
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Ketones 1a and b react with low-valent titanium salts to yield the trans-olefins 2a and b, respectively.From 1c the diene 4c is formed, probably via 2c.Ketone 1d is reduced to the hydrocarbon 7.Similarly the aromatic ketones 5 and 6 are reduced exclusively, yielding the hydrocarbons 8 and 9.While 10a shows coupling to 11a (94percent), ketone 10d does not react. - Preferred geometrics as well as strain energies are calculated using Allinger's force-field for 2, 3, and 11 (in all cases a-d).The calculated geometry of olefin 11a is compared with those known from the X-ray structure.
- Lenoir, Dieter,Lemmen, Peter
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p. 3112 - 3119
(2007/10/02)
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