- Epoxidation of Olefinic Compounds with Combined Use of Molecular Oxygen and Propionaldehyde Diethyl Acetal Catalyzed by Cobalt(II) Complex. Efficient Method for the Preparation of Acid-sensitive Epoxides
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Synthesis of acid-sensitive epoxides such as epoxide of bishomoallyl alcohol or chromene oxide was achieved by the epoxidation of corresponding olefins with combined use of molecular oxygen and propionaldehyde diethyl acetal catalyzed by cobalt(II) comple
- Yorozu, Kiyotaka,Takai, Toshihiro,Yamada, Tohru,Mukaiyama, Teruaki
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- Osmium-Catalyzed Oxidative Transformation of Alkenes to α-Ketols with Peracetic Acid
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The OsCl3-catalyzed oxidation of alkenes with peracetic acid at room temperature gives the corresponding α-ketols, which are important building units for synthesis of biological active compounds.
- Murahashi, Sun-Ichi,Naota, Takeshi,Hanaoka, Hidenori
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- Total synthesis of (+)-blennolide C and (+)-gonytolide C via spirochromanone
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We report the asymmetric total synthesis of (+)-blennolide C and (+)-gonytolide C isolated from endophytic fungi. The synthesis involved construction of a spirochromanone with a chiral quaternary carbon by the aldol reaction of o-hydroxyacetophenones and
- Adachi, Kanna,Hasegawa, Sho,Katakawa, Kazuaki,Kumamoto, Takuya
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supporting information
p. 4479 - 4482
(2017/10/30)
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- High-temperature Diels-Alder reactions: Transfer from batch to continuous mode
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The transfer of a Diels-Alder reaction of (cyclohexa-1,5-dien-1-yloxy) trimethylsilane 1 with α-acetoxyacrylonitrile 2 and acrylonitrile 8, respectively, from batch to continuous mode is presented, using standard and widely available laboratory equipment. A standard microwave-based system was used as probe for the transfer to flow reactors. Temperature and residence time have been optimized in small coiled-tube reactors and confirmed with two production runs in a flow reactor. The inherent increase in safety caused by the small volumes at high temperatures and the achieved productivity (approximately 100 g/h using acrylonitrile) are offering advantages over the batch mode which suffers from thermokinetic limitations for scale-up.
- Abele, Stefan,Hoeck, Stefan,Schmidt, Gunther,Funel, Jacques-Alexis,Marti, Roger
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experimental part
p. 1114 - 1120
(2012/08/27)
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- Stereoselective synthesis of optically active cyclitol precursors via a chemoenzymatic method
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Racemic α′-acetoxy α,β-unsaturated cyclohexanone has been converted to the corresponding enantiomerically enriched α′-hydroxylated and acetoxylated compounds with 97% ee via enzymatic resolution with PLE. OsO4-Catalyzed dihydroxylation of enant
- Oguzkaya, Funda,Sahin, Ertan,Tanyeli, Cihangir
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p. 3004 - 3009
(2007/10/03)
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- Chemoenzymatic synthesis of enantiomerically enriched 2-oxobicyclo[m.1.0] alkan-3-yl acetate derivatives
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Racemic α′-acetoxy α,β-unsaturated cyclopentanone and cyclohexanone have been resolved into the corresponding enantiomerically enriched α′-hydroxylated and acetoxylated compounds with 96-97% ee via PLE hydrolysis. Stereoselectivity in the palladium(II)-ca
- Oezdemirhan, Fazilet Devrim,Celik, Murat,Atli, Selin,Tanyeli, Cihangir
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p. 287 - 291
(2007/10/03)
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- A Novel Method for the Preparation of Acid-Sensitive Epoxides from Olefins with the Combined Use of Molecular Oxygen and Aldoacetal Catalyzed by a Cobalt(II) Complex
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An efficient synthesis of acid-sensitive epoxides, such as chromene oxide or epoxide of γ,δ-unsaturated alcohol, was successfully achieved by the oxygenation of corresponding olefins with the combined use of an atmospheric pressure of molecular oxygen and aldoacetal catalyzed by a cobalt(II) complex coordinated with the 1,3-diketone ligand.The reactions proceeded under mild and neutral conditions, and the desired epoxides were obtained in good yields.Neither overoxidation nor decomposition of the formed epoxide was observed under the present reaction conditions.Furthermore, various silyl enol ethers and silyl ketene acetals, acid-sensitive compounds, were also smoothly monooxygenated into the corresponding α-hydroxy ketones and α-hydroxy carboxylic acid esters, respectively.
- Yorozu, Kiyotaka,Takai, Toshihiro,Yamada, Tohru,Mukaiyama, Teruaki
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p. 2195 - 2202
(2007/10/02)
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- Ruthenium-Catalyzed Oxidative Transformation of Alkenes to α-Ketols with Peracetic Acid. Simple Synthesis of Cortisone Acetate
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The reactions of alkenes with peracetic acid in the presence of RuCl3 catalyst gave the corresponding α-ketols, which are important building units for synthesis of biological active compounds, such as cortisone acetate.
- Murahashi, Shun-Ichi,Saito, Takao,Hanaoka, Hidenori,Murakami, Yoshihide,Naota, Takeshi,et al.
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p. 2929 - 2930
(2007/10/02)
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- Aglycone fragmentation accompanies β-glucosidase catalyzed hydrolysis of salicortin, a naturally-occurring phenol glycoside
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Salicortin (1a), upon enzyme-mediated glycosidic hydrolysis, undergoes an unusual and rapid fragmentation-recombination reaction leading to 2 via postulated ortho-quinone methide (3) and enol (4) intermediates.
- Clausen, Thomas P.,Koller, John W.,Reichardt, Paul B.
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p. 4537 - 4538
(2007/10/02)
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- Oxidation of 2-trimethylsilyloxy-1,3-dienes with triphenyl phosphite ozonide. A regioselective α′-hydroxylation of α,β-unsaturated ketones
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The present work deals with a novel method for the introduction of hydroxyl group to the α′-carbon of α,β-unsaturated ketones using triphenyl phosphite ozonide.
- Iwata, Chuzo,Takemoto, Yoshiji,Nakamura, Ayatsugu,Imanishi, Takeshi
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p. 3227 - 3230
(2007/10/02)
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- THE OXYGENATION OF α-ISOPHORONE AND ITS SILYL ENOL ETHER WITH t-BuOOH IN THE PRESENCE OF METAL CATALYSTS
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Treatment of α-isophorone (1) with t-BuOOH in the presence of palladium(II) or copper(I) catalyst gives ketoisophorone (2) selectively.A similar treatment of silyl enol ether 7 derived from 1 affords 6-hydroxylisophorone 8.
- Hosokawa, Takahiro,Inui, Shiro,Murahashi, Shun-Ichi
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p. 1081 - 1082
(2007/10/02)
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