- Chloroperoxidase-catalyzed oxidation of conjugated dienoic esters
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The chloroperoxidase (CPO)-catalyzed oxidations of dienes conjugated to an ester group were studied using tert-butyl hydroperoxide as the terminal oxidant.
- Bougioukou, Despina J,Smonou, Ioulia
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p. 339 - 342
(2007/10/03)
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- Stereoselective synthesis of alkenylated malonic diamide using masked acyl cyanide
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A highly stereoselective synthesis of an alkenylated malonic diamide starting from a γ,δ-epoxy-α,β-unsaturated carboxamide was accomplished using the masked acyl cyanide (MAC: the protected hydroxymalonitrile) via palladium-catalyzed regio- and stereoselective carbon-carbon bond formation.
- Nemoto,Ibaragi,Bando,Kido,Shibuya
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p. 1319 - 1322
(2007/10/03)
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- Ruthenium-catalysed reductive cleavage of allylic esters with formic acid and triethylamine. Application to short-step synthesis of α-hydroxy acids
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Ruthenium-catalysed reductive cleavage reactions of allylic carboxylates and carbonates with formic acid and triethylamine to give olefins were explored.As an application of the ruthenium-catalysed processes, a new synthetic route to α-hydroxy acids has been discovered.The reductive cleavage of allylic esters is considered to proceed through ?-allylruthenium intermediates. Key words: Ruthenium; Catalysis; Reductive cleavage; Allyl; Formic acid
- Maruyama, Yooichiroh,Sezaki, Takao,Tekawa, Masafumi,Sakamoto, Toshiaki,Shimizu, Isao,Yamamoto, Akio
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p. 257 - 264
(2007/10/02)
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- Cobalt(II) catalysed reaction of alkenes with aliphatic aldehydes and molecular oxygen: Scope and mechanism
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A variety of cobalt(II) complexes can be prepared using Schiff's bases derived from aromatic aldehydes and amines or α-aminoesters. These complexes are versatile catalyst for the reaction between aliphatic aldehydes and various alkenes. The outcome of the reaction is controlled by the electronic nature of the alkene as the electron deficient alkenes undergo oxidative addition of aldehydes followed by dioxygen incorporation to yield 2-hydroxy(acyloxy)-4-oxoesters or nitriles whereas unactivated or electron rich alkenes afford the corresponding epoxides. These reactions are proceeding via a radical pathway and a common acylcobalt intermediate is proposed for the formation of 4 as well as the epoxides 7.
- Bhatia, Sonika,Punniyamurthy,Bhatia, Beena,Iqbal, Javed
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p. 6101 - 6122
(2007/10/02)
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- Cobalt(II) complex catalysed epoxidation with molecular oxygen
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Cobalt(II) complexes 1 or 2, catalyses the epoxidation of alkenes in the presence of molecular oxygen and 2-methylpropanal in high yields.
- Iqbal,Bhatia,Madhava Reddy
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p. 2285 - 2292
(2007/10/02)
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- A facile chemoenzymatic route to optically active 4,5-disubstituted-2E-hexenoate derivastives. II
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The reaction of (±) methyl 4,5-trans-epoxy-(2E)-hexenoate (1) with nucleophiles having heteroatoms in the presence of BF3 · Et2O gave the 4,5-anti-5-hydroxy-4- and/or 2,5-anti-5-hydroxy-2-substituted products. Among them, the (±)-4,5
- Akita,Umezawa,Takano,Oishi
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p. 680 - 684
(2007/10/02)
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- A facile chemoenzymatic route to optically active 4,5-disubstituted-2E-hexenoate derivatives. I
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The reaction of (±) methyl 4,5-trans-epoxy-2E-hexenoate (2) with aromatic nucleophiles having an electron-donating group in the presence of BF3 · Et2O gave the 4,5-anti-5-hydroxy-4- or/and 2,5-anti-5-hydroxy-2-substituted products. T
- Akita,Umezawa,Takano,Ohyama,Matsukura,Oishi
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- Olefin Epoxidation Using Elemental Fluorine
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F2 reacts with water and CH3CN, apparently to produce the relatively stable complex HOF*CH3CN.This is probably the best known oxygen-transfer reagent and can epoxidize olefins quickly and efficiently.Various types of alkenes including aliphatic, benzylic, enones, dienones, maleates, and fumarates have been examined, and all react with the reagent to produce the corresponding mono- or diepoxides in good to excellent yields.This epoxidation is fully stereospecific, and the configuration of the starting olefin is fully retained in the resulting oxirane.In cases where exceptionally stable oxocarbocations can be formed as in 1,1-diphenylethene, the reaction produces vicinal glycols in good yields.Since the origin of the epoxides' oxygen is in the water, this method is very suitable for introducing the isotopes 17O and 18O in various molecules.
- Rozen, Shlomo,Kol, Moshe
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p. 5155 - 5159
(2007/10/02)
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- Polyenic acids. II. Antifungal and bacteriostatic 4-bromo hexa-2,4 dienoic acids derivatives
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Some structural modifications of the dienic chain of 2,4 (2 E, 4 E)-hexadienoic acid - functionalisation, cyclic integration, epoxydation - were investigated. Only ω-oxydation allowed gain in bacteriostatic activity without reducing fungistatic activity of the reference compound: esters 10, 11 and 19. The corresponding acids 10a and 11a show a slight drop in fungistatic activity.
- Le Baut,Sparfel,Clairc,et al.
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p. 447 - 455
(2007/10/02)
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