- Gold imidazolium-based ionic liquids, efficient catalysts for cycloisomerization of γ-acetylenic carboxylic acids
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Ionic liquid stabilized gold(iii) chloride is shown to be a very active catalyst in the cyclization of sterically hindered and unhindered acetylenic carboxylic acid substrates even in the absence of a base. The Royal Society of Chemistry and the Centre Na
- Nea?u, Florentina,Parvulescu, Vasile I.,Michelet, Véronique,Gênet, Jean-Pierre,Goguet, Alexandre,Hardacre, Christopher
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- A highly active diradical cobalt(iii) catalyst for the cycloisomerization of alkynoic acids
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The first cobalt-catalysed cycloisomerisation of alkynoic acids is reported, thanks to the design of a well-defined diradical cobalt(iii) catalyst, in the absence of any additives. The high efficiency, regioselectivity and chemoselectivity are comparable to those of noble metal-based systems. The unique reactivity might be attributed to second coordination sphere effects.
- Leconte, Nicolas,Du Moulinet D'Hardemare, Amaury,Philouze, Christian,Thomas, Fabrice
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supporting information
p. 8241 - 8244
(2018/07/29)
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- Smaller, faster, better: Modular synthesis of unsymmetrical ammonium salt-tagged NHC-gold(i) complexes and their application as recyclable catalysts in water
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Facile access towards a small library of unsymmetrical ammonium salt-tagged N-heterocyclic carbene gold(i) complexes is described, and their application as recyclable catalysts in cyclization reactions of acetylenic carboxylic acids and amides to lactones and lactams, respectively, in aqueous media is demonstrated. Catalyst 1ab was applied in the synthesis of 2-epi-clausemarine A (16).
- Belger, Katrin,Krause, Norbert
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supporting information
p. 8556 - 8560
(2015/08/06)
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- Novel Pd heterogeneous catalysts for cycloisomerisation of acetylenic carboxylic acids
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The Pd-TPPTS complex (TPPTS - trisodium salt of 3,3′,3″- phosphanetriyl benzenesulfonic acid) and PdCl42- salt heterogenised onto Zn2AlNO3 layered double hydroxide (LDH) using an ion-exchange procedure, have bee
- Neau, Florentina,Proteescu, Loredana,Florea, Mihaela,Parvulescu, Vasile I.,Teodorescu, Cristian M.,Apostol, Nicoleta,Toullec, Patrick Y.,Michelet, Veronique
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experimental part
p. 2145 - 2149
(2011/02/24)
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- Synthesis of enol lactones via Cu(I)-catalyzed intramolecular O-vinylation of carboxylic acids
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With the catalysis of Cul/trans-W,W-dimethylcyclohexane-1,2-diamine, a number of carboxylic acids underwent efficient intramolecular O-vinylation with vinyl bromides leading to the synthesis of the corresponding five- and six-membered enol lactones. The same catalytic system also led to the efficient cycloisomerization of alkynoic acids.
- Sun, Changhul,Fang, Yewen,Li, Shuang,Zhang, Yue,Zhao, Qlwu,Zhu, Shana,Li, Chaozhong
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supporting information; experimental part
p. 4084 - 4087
(2009/12/06)
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- Au2O3 as a stable and efficient catalyst for the selective cycloisomerization of γ-acetylenic carboxylic acids to γ-alkylidene-γ-butyrolactones
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The high potential of commercially available Au2O3 as a catalyst in the cyclization of alkynes bearing carboxylic acids to the corresponding γ-alkylidene-γ-butyrolactones through a general, efficient and easy procedure is presented. The reaction shows a high degree of chemo-, regio-, and stereoselectivity. The 5-exo mode of cyclization and anti auration are a general trend for the Au2O3 catalyst. Georg Thieme Verlag Stuttgart.
- Toullec, Patrick Yves,Genin, Emilie,Antoniotti, Sylvain,Genêt, Jean-Pierre,Michelet, Véronique
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p. 707 - 711
(2008/12/21)
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- Ein neuer Katalysator mit einem wuerfelfoermigen PdMo3S4-Cluster fuer die Cyclisierung von Alkincarbonsaeuren zu Enol-Lactonen
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Keywords: Cyclisierungen; Katalyse; Lactone; Molybdaenverbindungen; Palladiumverbindungen
- Wakabayashi, Takanori,Ishii, Youichi,Ishikawa, Kazunari,Hidai, Masanobu
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p. 2268 - 2269
(2007/10/03)
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- Elimination Reactions of Terminal β-Oxy Selenoxides. Synthesis of Aryl and Vinyl Enol Ethers and of Furans, Oxazoles, and Thiazoles
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Elimination reactions of terminal selenoxides holding an alkoxy group in the β-position, RCH(OR)CH2SeOPh, are usually difficult and can give rise to complex reaction mixtures.We report that these reactions take place more easily whenever the oxygen atom is linked to an unsaturated group (-CH=CHR, -Ar, -CR=O, -CH=NR).These selenoxides are easily available, and the elimination reaction was employed to effect useful syntheses of both open-chain and cyclic aryl and vinyl enol ethers.Moreover, by simple isomerization with acids or bases the cyclic derivatives can be transformed into the corresponding furans.The same procedure has been employed to synthesize substituted oxazoles and thiazoles also.
- Tiecco, Marcello,Testaferri, Lorenzo,Tingoli, Marco,Marini, Francesca
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p. 1349 - 1354
(2007/10/02)
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- PALLADIUM(II) CATALYZED CYCLIZATION OF ALKYNOIC ACIDS
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Under the catalytic action of palladium(II) in the presence of triethylamine, 3-, 4-, and 5-alkynoic acids afford 3-buten-4-olides, 4-penten-4-olides,and 5-hexen-5-olide, respectively, in good to excellent yields.
- Lambert, Claude,Utimoto, Kiitiro,Nozaki, Hitosi
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p. 5323 - 5326
(2007/10/02)
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- Cyclisation of Acetylenecarboxylic Acid. Synthesis of γ-Methylenebutyrolactones
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Various γ-exo-methylenebutyrolactones have been synthesized in excellent yield by the cyclisation of acetylenecarboxylic acids in the presence of a catalytic amount of mercury(II) oxide.Cyclisation of terminal acetylene compounds proceeded regioselectively to give γ-exo-methylenebutyrolactones as the sole product.Disubstituted acetylenes also gave the (Z)-configurational enol lactone, but small amounts of an (E)-isomer of a γ-exo-enol lactone and a δ-lactone (α-pyrone) were also formed.Spectral properties and stereochemistry of the exo-enol lactones are also discussed.
- Yamamato, Makoto
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p. 582 - 587
(2007/10/02)
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