- Monoallylation and benzylation of dicarbonyl compounds with alcohols catalysed by a cationic cobalt(iii) compound
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Monoallylation and monoalkylation of diketones and β-keto esters with allylic and benzylic alcohols catalysed by [Cp*Co(CH3CN)3][SbF6]2(I) are reported. The method does not require any additive and affords regioselective products. The mechanistic investigations were done byin situ1H NMR spectroscopy as well as control experiments. It has been shown that reactions proceedviaη3-allyl complex formation or ally ether intermediate. The alkylation takes placeviaonly ether intermediate. The resulting allylated and alkylated products have been used for the synthesis of eleven new trisubstituted pyrazoles and one pyrazolone.
- Chandra Sau, Mohan,Mandal, Smita,Bhattacharjee, Manish
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p. 9235 - 9245
(2021/03/16)
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- Biocatalytic dynamic kinetic reductive resolution with ketoreductase from: Klebsiella pneumoniae: The asymmetric synthesis of functionalized tetrahydropyrans
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Ketoreductase from growing cells of Klebsiella pneumoniae (NBRC 3319) acts as an efficient reagent for converting racemic α-benzyl/cinnamyl substituted-β-ketoesters to the corresponding β-hydroxy esters with excellent yields and stereoselectivities (ee and de >99 %). The reactions described herein followed a biocatalytic dynamic kinetic reductive resolution (DKRR) pathway, which is reported for the first time with such substrates. It was found that the enzyme system can accept substituted mono-aryl rings with different electronic natures. In addition, it also accepts a substituted naphthyl ring and heteroaryl ring in the α-position of the parent β-ketoester. The synthesized enantiopure β-hydroxy esters were then synthetically manipulated to valuable tetrahydropyran building blocks.
- Barik, Rasmita,Halder, Joydev,Nanda, Samik
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p. 8571 - 8588
(2019/10/02)
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- Iridium/ N-Heterocyclic Carbene Complex-Catalyzed Intermolecular Allylic Alkylation Reaction
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N-Heterocyclic carbenes (NHCs) were found to be suitable ligands in Ir-catalyzed intermolecular allylic alkylation reaction. In the presence of a catalyst derived from [Ir(dncot)Cl]2 (dncot = dinaphthocyclooctatetraene) and triazolium salt L7,
- Bao, Can-Can,Zheng, Dong-Song,Zhang, Xiao,You, Shu-Li
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p. 4763 - 4772
(2019/01/04)
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- MMZNiY-Catalyzed Tsuji–Trost Type of Reaction: A Selective Mono/Bis Allylation of Dicarbonyl Compounds
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Abstract: An alternative method to Pd-catalyzed Tsuji–Trost reaction is developed and it provides a simpler route for the selective synthesis of a broad range of mono-/bis-allylated and cinnamylated 1,3-dicarbonyl compounds using MMZNiY catalyst at room temperature. Product selectivity can be controlled by the proper choice of catalyst. The catalyst was also well characterized by SEM, TEM, HRTEM, EDAX and X-ray analysis. Other advantages of catalyst like its ease of preparation, functional tolerance and its reusability are also highlighted.
- Senthilkumar, Samuthirarajan,Thangapriya, Cheirmakani,Alagumurugayee, Raman,Kumarraja, Mayilvasagam
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p. 2755 - 2763
(2017/09/14)
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- Palladium-Catalyzed Oxidative Cycloisomerization of 2-Cinnamyl-1,3-Dicarbonyls: Synthesis of Functionalized 2-Benzyl Furans
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A new palladium-catalyzed intramolecular oxidative cycloisomerization of readily available starting materials, 2-cinnamyl-1,3-dicarbonyls, has been demonstrated for the creation of structurally diverse 2-benzyl furans. The cycloisomerization occurs by a regioselective 5-exo-trig pathway. The reaction shows a broad substrate scope with good to excellent yields. Furthermore, a one-pot procedure has been executed by using readily available cinnamyl alcohols and 1,3-diketones. Cinnamyl verit: Palladium-catalyzed intramolecular oxidative cycloisomerization of readily available 2-cinnamyl-1,3-dicarbonyls affords structurally diverse 2-benzyl furans. The cycloisomerization occurs by a regioselective 5-exo-trig pathway, with a broad substrate scope in good to excellent yields. Furthermore, a one-pot procedure is executed by using readily available cinnamyl alcohols and 1,3-diketones
- Nallagonda, Rajender,Reddy, Reddy Rajasekhar,Ghorai, Prasanta
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supporting information
p. 14732 - 14736
(2015/10/19)
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- Highly selective palladium-benzothiazole carbene-catalyzed allylation of active methylene compounds under neutral conditions
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The Pd-benzothiazol-2-ylidene complex I was found to be a chemoselective catalyst for the Tsuji-Trost allylation of active methylene compounds carried out under neutral conditions and using carbonates as allylating agents. The proposed protocol consists in a simplified procedure adopting an in situ prepared catalyst from Pd2dba3 and 3-methylbenzothiazolium salt V as precursors. A comparison of the performance of benzothiazole carbene with phosphanes and an analogous imidazolium carbene ligand is also proposed.
- Monopoli, Antonio,Cotugno, Pietro,Zambonin, Carlo G.,Ciminale, Francesco,Nacci, Angelo
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supporting information
p. 994 - 999
(2015/08/19)
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- Transition-metal-free synthesis of substituted pyridines via ring expansion of 2-allyl-2H-azirines
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A new strategy to open the 2-allyl-2H-azirines by 1,8-diazabicyclo[5.4.0] undec-7-ene (DBU) promotion in metal-free conditions affording 1-azatrienes that in situ electrocyclize to the pyridines in good to excellent yields is reported. The reaction displays a broad substrate scope and good tolerance to a variety of substituents including aryl, alkyl, and heterocyclic groups. In addition, one-pot synthesis of pyridines from oximes via in situ formation of 2H-azirines was achieved.
- Jiang, Yaojia,Park, Cheol-Min,Loh, Teck-Peng
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supporting information
p. 3432 - 3435
(2014/07/21)
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- Dual platinum and pyrrolidine catalysis in the direct alkylation of allylic alcohols: Selective synthesis of monoallylation products
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A dual platinum- and pyrrolidine-catalyzed direct allylic alkylation of allylic alcohols with various active methylene compounds to produce products with high monoallylation selectivity was developed. The use of pyrrolidine and acetic acid was essential, not only for preventing undesirable side reactions, but also for obtaining high monoallylation selectivity. Two cats are better than one: The combined use of platinum and pyrrolidine catalysts enabled the direct alkylation of allylic alcohols with reactive methylene compounds. Pyrrolidine was essential for obtaining high selectivity of the monoallylation products, which were produced without the use of excess nucleophiles. cod=1,5- cyclooctadiene, EWG=electron-withdrawing group.
- Shibuya, Ryozo,Lin, Lu,Nakahara, Yasuhito,Mashima, Kazushi,Ohshima, Takashi
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supporting information
p. 4377 - 4381
(2014/05/06)
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- Enantioselective synthesis of 2-arylbicyclo[1.1.0]butane carboxylates
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The rhodium-catalyzed reaction of 2-diazo-5-arylpent-4-enoates can be controlled by the appropriate choice of catalyst and catalyst loading to form either 2-arylbicyclo[1.1.0]butane carboxylates or cyclohexene derivatives. Both products are produced in a
- Qin, Changming,Davies, Huw M. L.
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supporting information
p. 310 - 313
(2013/03/13)
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- A convergent general strategy for the functionalized 2-Aryl cycloalkylfused chromans: Intramolecular hetero-diels-alder reactions of ortho-quinone methides
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(Figure Presented) Five and six: 3, 4-Cyclopentyl- and cyclohexyl-fused 2-arylchromans could be readily prepared from the intramolecular hetero-Diels-Alder reactions of the corresponding ortho-quinone methide (o-QM) precursors tethered to the styrenes under mild reaction conditions. The products were obtained with good to excellent diastereoselectivity (up to > 99:1 dr; see scheme; MOM = methoxymethyl).
- Tummatorn, Jumreang,Ruchirawat, Somsak,Ploypradith, Poonsakdi
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supporting information; experimental part
p. 1445 - 1448
(2010/06/17)
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- Montmorillonite-entrapped sub-nanoordered Pd clusters as a heterogeneous catalyst for allylic substitution reactions
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(Chemical Equation Presented) Caught making a change: Stable sub-nanoordered Pd clusters within the interlayer spaces of montmorillonite efficiently catalyze heterogeneous allylic substitution reactions in which the coordinatively unsaturated Pd atoms enable facile formation of π-allylpalladium intermediates (see scheme). The catalyst is reusable without any loss of activity or selectivity.
- Mitsudome, Takato,Nose, Kenta,Mori, Kohsuke,Mizugaki, Tomoo,Ebitani, Kohki,Jitsukawa, Koichiro,Kaneda, Kiyotomi
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p. 3288 - 3290
(2008/03/11)
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- Ionic liquid/water as a recyclable medium for Tsuji-Trost reaction assisted by microwave
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An efficient microwave protocol is described for allylic substitution with various carbon and heteronucleophiles catalyzed by Pd(OAc)2/TPPTS in an [EMIm]BF4/H2O medium. The ionic liquid/water containing catalyst system can be recycled eight times without loss of activity.
- Liao, Meng-Chun,Duan, Xin-Hua,Liang, Yong-Min
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p. 3469 - 3472
(2007/10/03)
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- The polymer incarcerated method for the preparation of highly active heterogeneous palladium catalysts
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A new method named "the polymer incarcerated (PI) method" for preparing a heterogeneous palladium catalyst has been developed. The method is operationally simple, and the Pd catalyst prepared (PI Pd) is highly active for hydrogenation, carbon-carbon, and carbon-oxygen bond-forming reactions. Remarkable points are that the activity of PI Pd is higher than that of homogeneous Pd catalysts and that PI Pd is recovered by simple filtration and reused several times without loss of activity. The catalyst is expected to replace many heterogeneous palladium catalysts, especially Pd/C, which is often used in academia and industry, but recovery of which is difficult. Copyright
- Akiyama, Ryo,Kobayashi, Shu
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p. 3412 - 3413
(2007/10/03)
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- (π-Allyl)palladium complexes bearing diphosphinidenecyclobutene ligands (DPCB): Highly active catalysts for direct conversion of allylic alcohols
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The (π-allyl)palladium complex bearing an sp2-hybridized phosphorus ligand (DPCB-OMe: 1,2-bis(4-methoxyphenyl)-3,4-bis[(2,4,6-tri-tert-butylphenyl)phosphinidene]cyclobutene) efficiently catalyzes direct conversion of allylic alcohols in the absence of activating agents of alcohols such as Lewis acids. N-Allylation of aniline proceeds at room temperature to afford monoallylated anilines in 90-97% yields. C-Allylation of active methylene compounds is also successful at 50 °C using a catalytic amount of pyridine as a base, giving monoallylation products in 85-95% yields. The catalytic mechanism involving hydrido- and (π-allyl)palladium intermediates has been proposed on the basis of stoichiometric examinations using model compounds of presumed intermediates. Copyright
- Ozawa, Fumiyuki,Okamoto, Hideyuki,Kawagishi, Seiji,Yamamoto, Shogo,Minami, Tatsuya,Yoshifuji, Masaaki
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p. 10968 - 10969
(2007/10/03)
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- Solvent-free synthesis of 4,4-bis-functionalized-1,6-dienes and 1,6-diynes on the surface of neutral alumina
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An improved procedure has been developed for the synthesis of structurally varied 4,4-bis-functionalized-1,6-dienes and 1,6-diynes through regioselective alkylation of active methylene compounds with several unsymmetrical allyl bromides and propargyl brom
- Bhar, Sanjay,Kumar Chaudhuri, Subrata,Gopal Sahu, Santi,Panja, Chiradeep
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p. 9011 - 9016
(2007/10/03)
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- Selenocyclofunctionalization of β-ketoamides: Synthesis of substituted dihydrofurans
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Selenocyclofunctionalization of α-substituted β-ketoamides obtained from the aminolysis of the ethyl acetoacetate yielded dihydrofurans in moderate to good yields.
- Stefani, Hélio A.,Costa, Iguatemi M.,De O. Silva, Diogo,Menezes, Paulo H.,Rodrigues, Alessandro
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p. 141 - 152
(2007/10/03)
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- Palladium-tetraphosphine complex: An efficient catalyst for allylic substitution and Suzuki cross-coupling
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A new tetraphosphine, the cis-cis-cis-1,2,3,4-tetrakis (diphenylphosphinomethyl)cyclopentane (Tedicyp) has been synthesized and used in palladium-catalyzed reactions. This tetraphosphine in combination with [Pd(C3H5)Cl]2 affords a very efficient catalyst for coupling reactions. Turnover numbers of 980 000 for allylic amination, 9 800 000 for allylic alkylation and 97 000 000 for Suzuki cross-coupling can be obtained in the presence of this catalyst.
- Feuerstein,Laurenti,Doucet,Santelli
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p. 2320 - 2326
(2007/10/03)
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- Allylic substitution in water catalyzed by amphiphilic resin-supported palladium-phosphine complexes
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New amphiphilic resin-supported triarylphosphines PEP (1) were designed and prepared on polyethylene glycol-polystyrene graft copolymer (PEG-PS). Palladium complexes of 1, Pal(PEP)2 (4) and Pd(PEP) (5), catalyzed allylic alkylation of 3-acetoxy-1,3-diphenyl-1-propene (6) and cinnamyl acetate (7) with various nucleophiles including 1,3-dicarbonyl compounds, amino acids, sodium azide, and sodium sulfinate, to give quantitative yields of corresponding allylic substituted products in water.
- Danjo, Hiroshi,Tanaka, Daiki,Hayashi, Tamio,Uozumi, Yasuhiro
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p. 14341 - 14352
(2007/10/03)
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- Palladium(0)-catalyzed substitution of allylic substrates in perfluorinated solvents
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Palladium(O)-catalyzed alkylation reactions of allylic substrates can be performed using the new concept of fluorous biphasic system, allowing a very easy recycling of the catalyst.
- Kling, Robert,Sinou, Denis,Pozzi, Gianluca,Choplin, Agnes,Quignard, Francoise,Busch, Stefan,Kainz, Sabine,Koch, Daniel,Leitner, Walter
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p. 9439 - 9442
(2007/10/03)
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- New amphiphilic palladium-phosphine complexes bound to solid supports: Preparation and use for catalytic allylic substitution in aqueous media
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New amphiphilic palladium-phosphine complexes were designed and prepared on polyethylene glycol-polystyrene graft copolymer (PEG-PS) resin. The solid-supported palladium complexes showed high catalytic activity in allylic substitution reactions of allyl a
- Uozumi, Yasuhiro,Danjo, Hiroshi,Hayashi, Tamio
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p. 3557 - 3560
(2007/10/03)
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- Palladium(0)-Catalyzed Substitution of Allylic Substrates in an Aqueous-Organic Medium
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A palladium(0)-water soluble catalyst prepared in situ from palladium acetate and the sulfonated triphenyl phosphine P(C6H4-m-SO3Na)3 (or tppts) is an efficient catalyst for allylic substitution with various carbon and heteronucleophiles in an aqueous-organic medium, allowing a very easy separation of the product(s) and the recycling of the catalyst.
- Blart, Errol,Genet, Jean Pierre,Safi, Mohamed,Savignac, Monique,Sinou, Denis
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p. 505 - 514
(2007/10/02)
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- Ruthenium complex-catalyzed allylic alkylation of carbonucleophiles with allylic carbonates
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Allylic carbonates except for allyl methyl carbonate reacted with carbonucleophiles such as ethyl acetoacetate in the presence of a catalytic amount of Ru(cod)(cot) in N-methylpiperidine at 80 deg C to give the corresponding monoallylated carbonucleophiles in high yields with high regioselectivity.The regioselectivity was quite different from that in the palladium-catalyzed reactions.The allylation of carbonucleophiles using allyl methyl carbonate selectively gave the diallylated carbonucleophiles in high yields.
- Zhang, Shi-Wei,Mitsudo, Take-aki,Kondo, Teruyuki,Watanabe, Yoshihisa
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p. 197 - 207
(2007/10/02)
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- Stereoselective synthesis of 4- or 5-substituted 2-benzyl- and 2-benzoylpyrrolidines by means of anodic oxidation of δ-alkenylamines
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The anodic oxidation of the lithium amides of δ-alkenylamines 6a, 6b, 6c, 10a, and 10b gave stereoselectively cis-5-substituted 2-benzyl-1-methylpyrrolidines (7a, 7b, 7c) and 4-substituted 2-benzyl-1-methyl-pyrrolidines (11a, 11b) in high yields. The anod
- Tokuda,Miyamoto,Fujita,Suginome
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p. 747 - 756
(2007/10/02)
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- Palladium(0)-catalyzed substitution of allylic substrates in a two-phase aqueous-organic medium
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Palladium(0)-catalyzed substitution of allylic substrates are shown to occur in a two-phase aqueousorganic medium using the sulfonated triphenylphosphine P(C6H4-m-SO3Na)3 or (tppts) as the ligand, allowing the easy recovery and recycling of the catalyst.
- Safi, Mohamed,Sinou, Denis
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p. 2025 - 2028
(2007/10/02)
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- Copper(I) promoted C-C bond forming reactions: direct activation of allyl alcohols
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Allylic alcohols, acetates, carbonates and chlorides can be activated by copper(I) salts towards nucleophilic substitution by carbon nucleophiles under relatively mild conditions.
- Baruah, Jubaraj B.,Samuelson, Ashoka G.
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p. C57 - C60
(2007/10/02)
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- Influence du cuivre sur la substitution des enolates stables par divers halogenures allyliques
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The allylic substitution, by a variety of allylic halides, of stable enolates derived from diethyl malonate, ethyl cyanoacetate, ethyl acetoacetate and acetylacetone has been investigated.The yields and regioselectivity of these reactions are strongly influenced by cuprous ions (and their ligands).
- Cuvigny, Therese,Julia, Marc
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p. 121 - 138
(2007/10/02)
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