- Hydroxy-Directed Amidation of Carboxylic Acid Esters Using a Tantalum Alkoxide Catalyst
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We describe herein a new strategy for the chemoselective synthesis of amides by using a metal-catalyzed hydroxy-directed reaction. A hydroxy group located at the β-position of an ester group promoted the activation of a carbonyl group with a tantalum alkoxide catalyst followed by amidation reactions, leading to a wide variety of β-hydroxyamides with excellent chemeselectivity. The chemoselective amidation strategy can be extended to the catalytic synthesis of dipeptide derivatives, which remains challenging research subjects in modern organic synthesis.
- Tsuji, Hiroaki,Yamamoto, Hisashi
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supporting information
p. 14218 - 14221
(2016/11/13)
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- Base-catalyzed dehydrogenative Si-o coupling of dihydrosilanes: Silylene protection of diols
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The direct dehydrogenative coupling of 1,3- and 1,4-diols and dihydrosilanes is efficiently catalyzed by CsO(10 mol%), cleanly affording six- and seven-membered 1,3-dioxo-2-silacycles with dihydrogen as the sole by-product. Conversely, 1,2-diols do not yield the expected 1,3-dioxo-2- silacyclopentanes, essentially forming cyclic disiloxanes instead. Aside from the synthetic convenience, the procedure itself is also useful for straight-forward diol derivatization prior to GLC analysis. Georg Thieme Verlag Stuttgart · New York.
- Grajewska, Agnieszka,Oestreich, Martin
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supporting information; experimental part
p. 2482 - 2484
(2010/11/18)
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- Iron-catalyzed oxidative addition of alkoxycarbonyl radicals to alkenes with carbazates and air
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Clean and simple: Alkoxycarbonyl radicals generated from carbazates by iron catalysis in air underwent addition to a variety of alkenes to give the corresponding β-hydroxyesters (see scheme). The simple experimental procedure for this transformation has the added advantage that the reagents are environmentally friendly. R1,R2=alkyl, alkynyl, aryl, CO2Et; [Fe(Pc)]=iron phthalocyanine. Copyright
- Taniguchi, Tsuyoshi,Sugiura, Yuki,Zaimoku, Hisaaki,Ishibashi, Hiroyuki
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supporting information; experimental part
p. 10154 - 10157
(2011/02/24)
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- Ni-catalyzed activation of α-chloroesters: a simple method for the synthesis of α-arylesters and β-hydroxyesters
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Coupling reactions of α-chloroesters with aryl halides (α-arylation) or carbonyl compounds (Reformatsky) using nickel catalyst allow, under mild conditions, the preparation of various functionalized aryl propionic acid derivatives or β-hydroxyesters. In the synthesis of aryl propionic acid derivatives, the process is efficient with aryl halides bearing either electron-withdrawing or electron-donating groups.
- Durandetti, Muriel,Gosmini, Corinne,Périchon, Jacques
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p. 1146 - 1153
(2007/10/03)
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- Iron-catalysed Reformatsky-type reactions
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A Reformatsky-type reaction has been developed using iron catalysis in acetonitrile or DMF. Reduction of iron(II) bromide by manganese metal in acetonitrile provides a low-valent iron catalyst, which is the active species; under these conditions, α-chloro
- Durandetti, Muriel,Perichon, Jacques
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p. 1542 - 1548
(2007/10/03)
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- Iron-mediated electrochemical reaction of α-chloroesters with carbonyl compounds
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(Matrix presented) Reformatsky-type reactions have been performed efficiently using an electroassisted iron-complex catalysis. Valuable product such as β-hydroxyesters, ketones or nitriles are thus prepared with high yields.
- Durandetti, Muriel,Meignein, Clothilde,Perichon, Jacques
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p. 317 - 320
(2007/10/03)
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- Convenient Synthetic Sequence for the Preparation of Indanones
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A convenient and general methods is reported for the synthesis of indanones from aryl ketones or aldehydes.
- Smonou, Ioulia,Orfanopoulos, Michael
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p. 1387 - 1397
(2007/10/02)
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- CHLOROMETHYL-LITHIUM AND 1-CHLORO-2-METHYLPROP-1-ENYL-LITHIUM: USEFUL INTERMEDIATES IN THE SYNTHESIS OF UNSATURATED AND BIFUNCTIONALIZED COMPOUNDS
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The reaction of in situ generated chloromethyl-lithium with ketones (5) at -78 deg C afforded, after lithiation with lithium naphthalenide at the same temperature, β-oxidoalkyl-lithium compounds (6), which on reaction with electrophiles (deuterium oxide, dimethyl disulphide, carbon dioxide, cyclohexanone, and allyl bromide) yielded bifunctionalized compounds (7).When the lithiation step was carried out with lithium powder and at temperatures ranging between -60 deg C and 20 deg C, the corresponding decomposition of intermediates (6) derived from aldehydes and ketones (5) took place spontaneously giving the corresponding terminal or exocyclic olefins (11) regioselectively.The use of in situ generated 1-chloro-2-methylprop-1-enyl-lithium as organolithium reagent in the addition to carbonyl compounds (5) at -110 deg C, followed by transformation of the resulting chlorohydrin (13) into the corresponding methyl ether (14) (successive treatment with sodium hydride and methyl iodide at 0-20 deg C) gave, after lithiation with lithium phenanthrenide at room temperature, the corresponding substituted cumulenes (12).
- Barluenga, Jose,Fernandez-Simon, Jose L.,Concellon, Jose M.,Yus, Miguel
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p. 3339 - 3344
(2007/10/02)
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- β-Oxidofunctionalized Organolithium Intermediates from Ketones: A Simple New Access
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Chloromethyl-lithium generated in situ, reacts at -78 deg C with ketones (5) to afford, after lithiation with lithium naphthalenide, β-oxidoalkyl-lithium compounds (1), which on reaction with electrophiles (deuterium oxide, dimethyl disulphide, carbon dioxide, cyclohexanone, and allyl bromide) yield bifunctionalized compounds (6).
- Barluenga, Jose,Fernandez-Simon, Jose L.,Concellon, Jose M.,Yus, Miguel
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p. 915 - 916
(2007/10/02)
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- ELECTROREDUCTIVE COUPLING OF METALLYLCHLORIDE OR METHYL CHLOROACETATE WITH CARBONYL COMPOUNDS CAATLYZED BY NICKEL BIPYRIDINE COMPLEXES
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An efficient electrosynthesis of homoallyl alcohols or β-hydroxy esters in the presence of catalytic amounts of the NiBr2(2,2'-bipyridine) complex has been developed from mixed electrolysis of metellylchloride, or methyl chloroacetate with several carbonyl compounds, using a one-compartment cell equiped with a sacrificial zinc anode.
- Sibille, Soline,d'Incan, Esther,Leport, Luis,Massebiau, Marie-Claude,Perichon, Jacques
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- β-Substituted Organolithium Compounds from Chlorohydrins: Application to the Direct Synthesis of Bifunctionalized Organic Cpmpounds
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The reaction of different chlorohydrins with n-butyl-lithium at -78 deg C followed by metallation wiht lithium naphthalenide at the same temperature leads to very reactive organolithium compounds bearing an alkoxide function at the β-position with respect to metal.The reaction of these intermediates with several electriphiles leads to mono- as well as bi-functionalized organic compounds.Thus, treatment of these dianions with deuterium oxide, oxygen, carbon dioxide, benzyl bromide, dimethyl disulphide, and carbonyl compounds, gave 2-deuterioalcohols, 1,2-diols, β-hydroxy-acids, 2-benzyl alcohols, 2-hydroxy-thioethers, and 1,3-diols respectively.The preparation of β-substituted organolithium derivatives can be alternatively carried out starting from α-chloroketones by the same procedure.When the lithium atom is linked to a secondary carbon atom the dianions are very unstable and decompose, even at -100 deg C, by β-elimination yielding the corresponding olefins.
- Barluenga, Jose,Florez, Josefa,Yus, Miguel
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p. 3019 - 3026
(2007/10/02)
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