- Radical trifunctionalization of hexenenitrile via remote cyano migration
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A novel radical-mediated trifunctionalization of hexenenitriles via the strategy of remote functional group migration is disclosed. A portfolio of functionalized hexenenitriles are employed as substrates. After difunctionalization of the unactivated alken
- Chang, Chenyang,Wu, Xinxin,Zhang, Huihui,Zhu, Chen
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supporting information
p. 1005 - 1008
(2022/02/01)
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- Palladium(II)-catalyzed cross-coupling of diazo compounds and isocyanides to access ketenimines
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Diazo compounds and isocyanides are reactive functionalities and valuable building blocks commonly utilized in organic synthesis. Their cross-coupling for the synthesis of useful isolable ketenimines remains an unsolved challenge in synthetic chemistry. Herein, we report a general method for the preparation of ketenimines via a palladium-catalyzed cross-coupling of easily accessible diazo compounds with isocyanides. The reaction benefits from the use of readily available starting materials, a wide substrate scope, high functional group tolerance, and a high yield in products, and the resultant ketenimines are amenable to further functionalization. Experimental findings and DFT calculations unambiguously corroborate the initial formation of a Pd(II)? isocyanide complex as the active catalytic species, which enables the cross-coupling reaction via a migratory insertion of Pd(II)? carbene into isocyanide, with evidence suggesting that the oxidation state of Pd(II) remains unchanged during the reaction.
- Bi, Xihe,Liu, Zhaohong,Cao, Shanshan,Wu, Jiayi,Zanoni, Giuseppe,Sivaguru, Paramasivam
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p. 12881 - 12887
(2020/11/18)
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- Oscillating Emission of [2]Rotaxane Driven by Chemical Fuel
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A molecular shuttle consisting of a dibenzo-24-crown-8 macrocycle and an axle with two degenerate peripheral triazolium stations, a central dibenzyl ammonium station, and two anthracenes stoppers was exposed to 2-cyano-2-phenylpropanoic acid as a chemical fuel. Protonation/deprotonation of the amine reversibly switches the rotaxane from a static and little emissive to a dynamic fluorescent shuttling device, the latter exhibiting rapid motion (15 kHz at 25 °C). Four fuel cycles were run.
- Ghosh, Amit,Paul, Indrajit,Adlung, Matthias,Wickleder, Claudia,Schmittel, Michael
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supporting information
p. 1046 - 1049
(2018/02/23)
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- AlCl3 catalyzed coupling of: N-benzylic sulfonamides with 2-substituted cyanoacetates through carbon-nitrogen bond cleavage
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A new cross-coupling reaction of N-benzylic sulfonamides with 2-substituted cyanoacetates for the synthesis of 2-substituted benzylbenzene was reported. In the presence of AlCl3, a broad range of N-benzylic sulfonamides reacted smoothly with 2-substituted cyanoacetates to afford structurally diverse benzylbenzenes in moderate to excellent yields. The conversion could be enlarged to gram-scale efficiently. The practicability of this approach was further manifested in the synthesis of a related bioactive agent with high anti-inflammatory activity.
- Hu, Chen,Hong, Gang,Qian, Xiaofei,Kim, Kwang Rim,Zhu, Xiaoyan,Wang, Limin
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supporting information
p. 4984 - 4991
(2017/07/10)
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- UV-mediated decomposition of diazomalonates in benzene: Unexpected access to functionalized bicyclo[3.2.0]heptane skeleton
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Upon irradiation with 300-nm UV light, the photolysis of diazomalonates in benzene unexpectedly affords 2,6-dicarboxylate bicyclo[3.2.0]hepta-2,6-dienes in low yields. These products are proven to be derived from cyclohepta-1,3,5-triene intermediates presumably via a tandem 1,5-carboxylate migration/[2+2] cycloaddition sequence.
- Chiang, Yi-Jung,Zhu, Jia-Liang
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supporting information
p. 3081 - 3084
(2017/07/17)
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- THIOAMIDES AND AMIDES FOR CONTROLLING ANIMAL PESTS
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The invention relates to the use of a compound of formula (I) or a salt thereof for combating animal pests, where the symbols and indices are defined in the specification.
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Page/Page column 215
(2015/07/07)
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- Arylation of diethyl malonate and ethyl cyanoacetate catalyzed by palladium/di-tert-butylneopentylphosphine
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α-Arylated carbonyl derivatives are important structural motifs in many natural products and pharmaceutically active compounds. Although arylation of simple monocarbonyl compounds is a well-established methodology, metal-catalyzed arylation of β-dicarbonyl derivatives is significantly more challenging. The ability of β-dicarbonyl anions to bind to palladium in a κ2-O,O mode, rather than the κ1-C-bound mode required for bond formation, often results in the deactivation of catalyst systems. The C-bound form of the enolate can be favored through the use of sterically demanding ligands. Herein, we report that the sterically demanding di-tert-butylneopentylphosphine (DTBNpP) ligand in combination with Pd(dba)2 provides an effective catalyst for the coupling of aryl bromides and chlorides with diethyl malonate. The Pd/DTBNpP system also catalyzes the coupling of aryl bromides with ethyl cyanoacetate.
- Semmes, Jeffrey G.,Bevans, Stephanie L.,Mullins, C. Haddon,Shaughnessy, Kevin H.
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supporting information
p. 3447 - 3450
(2015/02/05)
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- Synergistic effect of a bis(proazaphosphatrane) in mild palladium-catalyzed direct α-arylations of nitriles with aryl chlorides
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The effect of a bis(proazaphosphatrane) ligand on the palladium-catalyzed direct α-arylation of nitriles with various aryl chlorides under mild conditions is reported. Comparisons of the catalytic properties of this ligand with those of three related mono(proazaphosphatrane)s under the same reaction conditions revealed that bis(proazaphosphatrane) displayed a synergistically enhanced activity. In the presence of the bis(proazaphosphatrane) ligand, ethyl cyanoacetate and primary as well as secondary nitriles were efficiently coupled with a wide variety of aryl chlorides that contained electron-rich, electron-poor, and electron-neutral groups.
- Han Kim, So,Jang, Wonseok,Kim, Min,Verkade, John G.,Kim, Youngjo
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p. 6025 - 6029
(2015/03/30)
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- COMPOUNDS FOR THE REDUCTION OF β-AMYLOID PRODUCTION
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The present disclosure provides a series of compounds of the formula (I), which modulate β-amyloid peptide (β-ΑΡ) production and are useful in the treatment of Alzheimer's Disease and other conditions affected by β-amyloid peptide (β-ΑΡ) production.
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Page/Page column 155
(2012/08/08)
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- Copper(I) enolate complexes in α-arylation reactions: Synthesis, reactivity, and mechanism
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Copper is all bound up: The copper-catalyzed α-arylation of carbonyl compounds occurs through oxidative addition of iodoarenes to the C-bound Cu I enolate species 1 to form an aryl-CuIII intermediate (see scheme). Computational results provide insight into the origins of the relative reactivity of various CuI enolate complexes in the reactions with iodoarenes. Copyright
- Huang, Zheng,Hartwig, John F.
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supporting information; experimental part
p. 1028 - 1032
(2012/03/09)
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- COMPOUNDS FOR THE REDUCTION OF β-AMYLOID PRODUCTION
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The present disclosure provides a series of compounds of the formula (I) which modulate β-amyloid peptide (β-AP) production and are useful in the treatment of Alzheimer's Disease and other conditions affected by β-amyloid peptide (β-AP) production.
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Page/Page column 170-171
(2011/02/24)
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- Construction of 1,2,5-tricarbonyl compounds using methyl cyanoacetate as a glyoxylate anion synthon combined with copper(I) iodide-catalyzed aerobic oxidation
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A practical and efficient synthesis of various 1,2,5-tricarbonyl compounds is described. The synthesis has been carried out by a conjugate addition of methyl cyanoacetate to the β-position of α,β-unsaturated carbonyl compounds and a subsequent copper(I) iodide-catalyzed aerobic oxidation. In addition, various α-aryl- and α-alkyl-α-keto esters have been synthesized using a similar approach. Copyright
- Kim, Se Hee,Kim, Ko Hoon,Kim, Jae Nyoung
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supporting information; experimental part
p. 3335 - 3339
(2012/01/19)
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- Deacylative allylation: Allylic alkylation via retro-Claisen activation
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A new method for allylic alkylation of a variety of relatively nonstabilized carbon nucleophiles is described herein. In this process of "deacylative allylation", the coupling partners, an allylic alcohol and a ketone pronucleophile, undergo in situ retro-Claisen activation to generate an allylic acetate and a carbanion. In the presence of palladium, these reactive intermediates undergo catalytic coupling to form a new C-C bond. In comparison to unimolecular decarboxylative allylation, a commonly utilized method for allylation of carbon anions, deacylative allylation is an intermolecular process. Moreover, deacylative allylation allows the direct coupling of readily available allylic alcohols. Lastly, the full utility of deacylative allylation is demonstrated by the rapid construction of a variety 1,6-heptadienes via 3-component couplings.
- Grenning, Alexander J.,Tunge, Jon A.
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supporting information; scheme or table
p. 14785 - 14794
(2011/11/04)
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- Palladium-catalyzed one-pot synthesis of 2-alkyl-2-arylcyanoacetates
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(Chemical Equation Presented) A one-pot procedure for the synthesis of 2-alkyl-2-arylcyanoacetates based on a Pd(OAc)2/DPPF (DPPF = 1,1′-diphenylphosphino ferreocene)-catalyzed enolate arylation followed by in situ alkylation has been developed. This procedure tolerates a diverse range of aryl and heteroaryl bromides, and provides a rapid entry to a variety of 2-alkyl-2-arylcyanoacetates in good to excellent yield.
- Wang, Xiang,Guram, Anil,Bunel, Emilio,Cao, Guo-Qiang,Allen, Jennifer R.,Faul, Margaret M.
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p. 1643 - 1645
(2008/09/17)
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- PROCESS FOR PRODUCING PHOSPHONIUM BORATE COMPOUND, NOVEL PHOSPHONIUM BORATE COMPOUND, AND METHOD OF USING THE SAME
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The invention relates to a phosphonium borate compound represented by Formula (I) (hereinafter, the compound (I)). The invention has objects of providing (A) a novel process whereby the compound is produced safely on an industrial scale, by simple reaction operations and in a high yield; (B) a novel compound that is easily handled; and (C) novel use as catalyst. ????????Formula (I) : (R1)(R2)(R3)PH·BAr4?????(I) wherein R1, R2, R3 and Ar are as defined in the specification. The process (A) includes reacting a phosphine with a) HCl or b) H2SO4 to produce a) a hydrochloride or b) a sulfate; and reacting the salt with a tetraarylborate compound. The compound (B) has for example a secondary or tertiary alkyl group as R1 and is easily handled in air without special attention. The use (C) is characterized in that the compound (I) is used instead of an unstable phosphine compound of a transition metal complex catalyst for catalyzing C-C bond, C-N bond and C-O bond forming reactions and the compound produces an effect that is equal to that achieved by the transition metal complex catalyst.
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Page/Page column 64
(2008/06/13)
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- Method of forming a carbon-carbon or carbon-heteroatom linkage
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The invention relates to a method of creating a carbon-carbon or carbon-heteroatom linkage by reacting an unsaturated compound bearing a leaving group and a nucleophilic compound. More specifically, the invention relates to the creation of a carbon-nitrogen linkage involving the arylation of nitrogenous organic derivatives. The inventive method consists in creating a carbon-carbon or carbon-heteroatom linkage by reacting an unsaturated compound bearing a leaving group and a nucleophilic compound providing a carbon atom or a heteroatom (HE) capable of being substituted for the leaving group, thereby creating a C—C or C-HE linkage. The invention is characterised in that the reaction is carried out in the presence of an effective quantity of a catalyst based on copper and at least one ligand comprising at least one imine function and at least one additional nitrogen atom as chelating atoms
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Page/Page column 39
(2010/02/14)
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- An efficient and mild CuI/L-proline-catalyzed arylation of acetylacetone or ethyl cyanoacetate
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The coupling reaction of aryl iodides with acetylacetone or ethyl cyanoacetate under catalysis of CuI/L-proline works at relatively mild conditions to provide 3-aryl-2, 4-pentanediones and α-aryl cyanoacetates in moderate to good yields. Georg Thieme Verlag Stuttgart.
- Jiang, Yongwen,Wu, Nan,Wu, Haihong,He, Mingyuan
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p. 2731 - 2734
(2007/10/03)
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- Highly efficient and mild copper-catalyzed N- and C-arylations with aryl bromides and iodides
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Mild, efficient, copper-catalyzed N-arylation procedures for nitrogen heterocycles, amides, carbamates, and C-arylation procedures for malonic acid derivatives have been developed that afford high yields of arylated products with excellent selectivity. The N-arylation of imidazole with aryl bromides or iodides was found to be greatly accelerated by inexpensive, air-stable catalyst systems, combining catalytic copper salts or oxides with a set of structurally simple chelating ligands. The reaction was shown to be compatible with a broad range of aryl halides, encompassing sterically hindered, electron-poor, and electron-rich ones, providing the arylated products under particularly mild conditions (50-82°C). The lower limit in ligand and catalyst loading and the scope of Ullmann-type condensations catalyzed by complexes bearing those ligands with respect to the nucleophile class have also been investigated. Chelating Schiff base Chxn-Py-Al (1c) generates a remarkably general copper catalyst for N-arylation of pyrrole, indole, 1,2,4-triazole, amides, and carbamates; and C-arylation of diethyl malonate, ethyl cyanoacetate, and malononitrile with aryl iodides under mild conditions (50-82°C). The new method reported here is the most successful to date with regard to Ullmann-type arylation of some of these nucleophiles.
- Cristau, Henri-Jean,Cellier, Pascal P.,Spindler, Jean-Francis,Taillefer, Marc
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p. 5607 - 5622
(2007/10/03)
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- P(i-BuNCH2CH2)3N: An efficient ligand for the direct α-arylation of nitriles with aryl bromides
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A new catalyst system for the synthesis of α-aryl-substituted nitriles is reported. The bicyclic triaminophosphine P(i-BuNCH 2CH2)3N (1b) serves as an efficient and versatile ligand for the palladium-catalyzed direct α-arylation of nitriles with aryl bromides. Using ligand 1b, ethyl cyanoacetate and primary as well as secondary nitriles are efficiently coupled with a wide variety of aryl bromides possessing electron-rich, electron-poor, electron-neutral, and sterically hindered groups.
- You, Jingsong,Verkade, John G.
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p. 8003 - 8007
(2007/10/03)
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- A convenient and efficient palladium-catalyzed system for cross-coupling of aryl bromides with active methylene compounds
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A simply catalytic system containing palladium-phosphine complex, generated in situ from PdCl2/tert-phosphino ligand in pyridine, has been systematically studied in the cross-coupling of bromobenzene with malononitrile or ethyl cyanoacetate anion. The effect of molar ratio of phosphine ligand to PdCl2 on the activity of the coupling was also discussed. It is found that the catalytic system has highly catalytic activity to produce aryl malononitriles and cyanoacetates in considerable yields (67-90%) when the substituted aryl bromides were used as substrates.
- Gao, Chengwei,Tao, Xiaochun,Qian, Yanlong,Huang, Jiling
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p. 1716 - 1718
(2007/10/03)
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- A General Method for the Direct α-Arylation of Nitriles with Aryl Chlorides
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The long-standing challenge of developing a general method for the title methodology is met for a broad range of aryl chlorides through the use of bicyclic P(iBuNCH2CH2)3N (1) as a bulky electron-rich ligand for palladium (see scheme, dba = dibenzylideneacetone).
- You, Jingsong,Verkade, John G.
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p. 5051 - 5053
(2007/10/03)
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- Palladium-catalyzed arylation of malonates and cyanoesters using sterically hindered trialkyl- and ferrocenyldialkylphosphine ligands
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Palladium-catalyzed reactions of aryl bromides and chlorides with two common stabilized carbanions - enolates of dialkyl malonates and alkyl cyanoesters - are reported. An exploration of the scope of these reactions was conducted, and the processes were shown to occur in a general fashion. Using P(t-Bu)3 (1), the pentaphenylferrocenyl ligand (Ph5C5)Fe(C5H4)P(t-Bu) 2 (2), or the adamantyl ligand (1-Ad)P(t-Bu)2 (3), reactions of electron-poor and electron-rich, sterically hindered and unhindered aryl bromides and chlorides were shown to react with diethyl malonate, di-tertbutyl malonate, diethyl fluoromalonate, ethyl cyanoacetate, and ethyl phenylcyanoacetate. Although alkyl malonates and ethyl alkylcyanoacetates did not react with aryl halides using these catalysts, the same products were formed conveniently in one pot from diethylmalonate by cross-coupling of an aryl halide in the presence of excess base and subsequent alkylation.
- Beare, Neil A.,Hartwig, John F.
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p. 541 - 555
(2007/10/03)
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- Synthesis of annelated analogues of 6-benzyl-1-(ethoxymethyl)-5-isopropyluracil (MKC-442) using 1,3-oxazine-2,4(3H)-diones as key intermediates
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Condensation of ethyl 3-phenyl-2-oxocyclopentanecarboxylate 5 with 2-(S-methylthio)isourea followed by hydrolysis with HC1 gave 6,7-dihydro-7-phenylcyclopenta[e][1,3]oxazine-2,4(3H,5H)-dione (10a). 7,8-Dihydro-8-phenyl-6H-cyclohexa[e][1,3]oxazine-2,4(3H,5H)-dione (10b) was synthesised by reacting 2-phenylcyclohexanone (9b) with N-(chlorocarbonyl) isocyanate. The oxazines 10a,b were reacted with ammonia to obtain the corresponding uracil derivatives 12a,b which after silylation were alkylated with diethoxymethane using trimethylsilyl triflate (TMS-triflate) as the catalyst or alkylated with chloromethyl ethyl ether to give annelated MKC-442 analogues 2,3 which are locked in a conformation close to the one of MKC-442. In spite of this, only moderate activities were found against HIV-1 for the annelated analogues of MKC-442. The Royal Society of Chemistry 2000.
- Larsen, Janus S.,Christensen, Lene,Ludvig, Gitte,Jorgensen, Per T.,Pedersen, Erik B.,Nielsen, Claus
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p. 3035 - 3038
(2007/10/03)
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- Selective Mono-methylation of Arylacetonitriles and Methyl Arylacetates by Dimethyl Carbonate
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Both arylacetonitriles and methyl arylacetates react with dimethyl carbonate (DMC) (20 molar excess) at 180 - 200 deg C in the presence of K2CO3 to produce monomethylated 2-arylpropionitriles and methyl 2-arylpropionates, respectively, with a selectivity >99.5percent.The reaction, with wide application, proceeds by DMC acting as a methoxycarbonylating agent towards the ArCH-X anion (X = CN, CO2Me) and as a methylating agent to ArC-(CO2Me)X.DMC also proved to be the best solvent for such reactions.
- Selva, Maurizio,Marques, Carlos Alberto,Tundo, Pietro
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p. 1323 - 1328
(2007/10/02)
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- A Convenient Synthesis of Some Arylated Phenylsulfonylacetonitriles and Ethyl Cyanoacetates Using Organo-iron Complexes
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A general method for the synthesis of some arylated phenylsulfonylacetonitriles 6a-g, 10a, b and 16 and ethyl cyanoacetates 7a-d and 11a, b is described.Nucleophilic substitution of the cyclopentadienyliron complexes of chloroarenes 1a-g with phenylsulphonylacetonitrile 2 or ethyl cyanoacetate 3 in the presence of potassium carbonate in DMF, at room temperature under a nitrogen atmosphere gave cyclopentadienyliron complexes of arylated phenylsulphonylacetonitriles 4a-g, 8a, b and 15 and ethyl cyanoacetates 5a-d and 9a, b in very good yields (71-94percent).Photolysis of these complexes liberated the arenes (70-91percent).To demonstrate the versatility of this methodological approach, reactions of both carbon nucleophiles 2, 3 with dimethyl chlorobenzene complexes 1h, j gave the desired products 8a, 9a, 12 and 13 without significant steric effect.This synthesis is advantageous over all those previously reported and should be a practical route to a variety of alkanoic acid and heterocyclic precursors.
- Abd-El-Aziz, Alaa S.,Denus, Christine R. de
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p. 293 - 298
(2007/10/02)
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- AROMATIC NUCLEOPHILIC SUBSTITUTION ON η6-Cr(CO)3-COMPLEXED HALOGENOARENES: ARYLATION OF SECONDARY CARBANIONS
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The paper deals with the aromatic nucleophilic substitution on η6-Cr(CO)3-complexed fluorobenzene and ortho-, meta-, and para-dichlorobenzenes with stabilized carbanions, both under phase-transfer conditions (PTC) and in DMSO solution.In the case of the η6-Cr(CO)3-complexed ortho-, meta-, and para-dichlorobenzenes only one chlorine atom is replaced by the carbanions.
- Baldoli, Clara,Buttero, Paola Del,Licandro, Emanuela,Maiorana, Stefano
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p. 409 - 414
(2007/10/02)
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- Cross-Coupling of N-Heteroaryl Halides with Active Methylene Compounds in the Presence of Tetrakis(triphenylphosphine)palladium
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The cross-coupling of 3-iodo- and 3-bromopyridine with the carbanions derived from ethyl cyanoacetate and malononitrile in the presence of tetrakis(triphenylphosphine)palladium in 1,2-dimethoxyethane gave ethyl α-cyanopyridine-3-acetate and 3-pyridinemalononitrile in moderate yields.This palladium-catalyzed cross-coupling proceeded smoothly with halopyrimidines, haloquinolines, haloisoquinones, and also bromobenzene.Keywords - tetrakis(triphenylphosphine)palladium; aryl halide; N-heteroaryl halide; ethyl cyanoacetate; malononitrile; ethyl α-cyanoareneacetate; arenemalononitrile.
- Sakamoto, Takao,Katoh, Eisaku,Kondo, Yoshinori,Yamanaka, Hiroshi
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p. 1664 - 1668
(2007/10/02)
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- PREPARATION AND SOME REACTIONS OF 4- AND 5-ARYL-4,5-DIHYDROPYRIDAZIN-3(2H)-ONES
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Efficient preparations of 4- and 5-phenyl-4,5-dihydropyridazin-3(2H)-ones have been developed, the main reactions of these compounds have been studied, and the synthetic routes have been used to give analogues with substituents in the phenyl rings.In the best synthesis of the 4-phenyldihyropyridazinone (72 percent overall yield) the product was obtained from phenylacetic acid by three simple stages.This approach was applied in preparations of the 2- and 4-hydroxyphenyl compounds and, in conjunction with a recent method for amine protection, the 4-aminophenyl analogue.A four stage synthesis starting from benzaldehyde gave the 5-phenyldihydropyridazinone in 47 percent overall yield; hydroxybenzaldehydes were similarly converted into 5-(allyloxyphenyl)dihydropyridazinones.Oxidation to phenylpyridazinones occured more readily with the 4- and 5-phenyldihydropyridazinones than with the 6-phenyl isomer.The 4- and 5-dihydropyridazinones were smoothly reduced to tetrahydropyridazinones by hydrogenation over platinum but were uneffected by palladium in the presence of hydrazine or cyclohexene.
- Breukelman, Stephen P.,Meakins, G. Denis
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p. 1627 - 1636
(2007/10/02)
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- SYNTHESIS AND STRUCTURE OF 5-PHENYLCYCLOPHOSPHAMIDES
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5-Phenylcyclophosphamides have been sythesized from benzyl cyanide via carbethoxylation, reduction, and finally condensation with bis(2-chloroethyl)-phosphoramidic dichloride.The two diastereomers have been separated and their structures have been assigned on the basis of ir, P-31 nmr and X-ray crystallography.
- Shih, Yun-Er,Wang, Jy-Shih
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p. 2799 - 2803
(2007/10/02)
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- Process for preparing esters of cyanoacetic acids
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A novel process for preparing an ester of cyanoacetic acid which comprises reacting a cyanoacetaldehyde acetal, hydroxylamine and an alcohol.
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-
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- SOME REMARKS ON THE SEEFELDER METHOD OF VINYLATION OF CH-ACIDS
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The relative reactivity sequence: PhCH(CN)COOMe > PhCH(CN)COOEt >> PhCH(COOMe)2 > n-BuCH(COOMe)2 > (Me)2CHCH(COOMe)2, for cadmium stearate catalyzed reactions of these CH-acids with acetylene has been established.Different catalytic efficiency of zinc and cadmium stearate towards particular kinds of CH-acids has been revealed.The usefulness of cadmium stearate for vinylation of monosubstituted acetoacetic esters has been demonstrated.
- Bukowska, Maria,Prejzner, Jan
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p. 867 - 873
(2007/10/02)
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- THERMOLYSIS AND PHOTOLYSIS OF 4-DIAZO-1,2,3-TRIAZOLES IN BENZENOID SOLVENTS, SYSTEMS WHICH REVEAL DECOMPOSITION OF DIAZO COMPOUNDS TO CARBENES TO DIAZO COMPOUNDS TO CARBENES.
-
4-Diazo-1,2,3-triazoles thermolyze and photolyze to 4H-1,2,3-triazolylidenes which (1) convert benzenes to 4-phenyl-1,2,3-triazoles or/and (2) isomerize to α-diazonitriles which react carbenically with benzenes by addition, ring-expansion or substitution processes.
- Hui, H. K.-W.,Shechter, H.
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p. 5115 - 5118
(2007/10/02)
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- "Wolf and lamb" reactions: Equilibrium and kinetic effects in multipolymer systems
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Two reagents reacting avidly with each other in solution are rendered mutually inactive by attaching each to a separate batch of insoluble polymer. Two-stage reactions in which a soluble reagent reacts first with one polymeric reagent and the product with the second polymeric reagent afford advantages over analogous reactions in solution. In acylation reactions of carbon acids, the simultaneous use of a polymeric strong base and a polymeric acylating reagent proved to be superior to the use of soluble reagents, both for bringing about quantitative acylations and for coping with undesirable side reactions. New polymeric strong bases were prepared: polymeric trityllithium, para-substituted trityllithium polymers, and polymeric lithium diisopropylamide. Active esters of polymeric o-nitrophenol and N-1-hydroxybenzotriazole were used as acylation reagents. The scope and limitation of these reactions and their application to general multiphase systems are discussed.
- Cohen,Kraus,Patchornik
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p. 7620 - 7629
(2007/10/02)
-
