- Synthesis and anti-retroviral activity of novel 5′-deoxy-5′,5′-difluoro-threosyl nucleoside phosphonic acid analogs
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Novel 5′-deoxy-5′,5′-difluoro-threose purine phosphonic acid analogs were designed and synthesized from 2-propanone-1,3-diacetate. Direct displacement of the triflate intermediate 12 with diethyl (lithiodifluoromethyl) phosphonate provided the correspondi
- Kim, Seyeon,Jee, Jun-Pil,Hong, Joon Hee
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- Acetic Acid as a Highly Reactive and Easily Separable Catalyst for the Oxidative Cleavage of Tetrahydrofuran-2-methanols to γ-Lactones
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[4-Iodo-3-(isopropylcarbamoyl)phenoxy]acetic acid was developed as a highly reactive and easily separable catalyst for the oxidative cleavage of tetrahydrofuran-2-methanols to γ-lactones in the presence of Oxone (2KHSO 5 ·KHSO 4 ·K 2 SO 4) as the co-oxidant. The reactivity of this new catalyst was considerably greater than that of our previously reported catalyst, 2-iodo-N-isopropylbenzamide. The new catalyst and product were easily separated by only liquid-liquid separation without chromatography. In addition, using a mixture of nitromethane and N, N-dimethylformamide as the solvent and heating enabled a low catalyst loading, a short reaction time, and high product yield. Oxidative cleavage using the new catalyst can be used as a practical and efficient method for synthesizing γ-lactones.
- Yakura, Takayuki,Fujiwara, Tomoya,Nishi, Hideyuki,Nishimura, Yushi,Nambu, Hisanori
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supporting information
p. 2316 - 2320
(2018/10/20)
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- Baeyer–Villiger monooxygenase-catalyzed desymmetrizations of cyclobutanones. Application to the synthesis of valuable spirolactones
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A series of γ-butyrolactone derivatives, including some spiranic ones, was obtained through desymmetrization of the corresponding prochiral 3-substituted cyclobutanones via Baeyer–Villiger monooxygenase (BVMO)-catalyzed oxidation. After reaction optimization using several commercial enzymes, both antipodes of various lactones were synthesized in most cases with >90% conversion and >80% enantiomeric excess under mild reaction conditions. In some cases alcohol formation was also observed (up to 40% conversion) as an undesired side reaction due to the presence of alcohol dehydrogenases in these preparations. Selected transformations were achieved on a 100 mg scale showing the possibilities of these oxidative biocatalysts as a new source of highly interesting compounds.
- Rodríguez-Mata, María,Lavandera, Iván,Gotor-Fernández, Vicente,Gotor, Vicente,García-Cerrada, Susana,Mendiola, Javier,de Frutos, óscar,Collado, Iván
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p. 7268 - 7275
(2016/10/26)
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- Efficient Oxidative Cleavage of Tetrahydrofuran-2-methanols to γ-Lactones by a 2-Iodobenzamide Catalyst in Combination with Oxone
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An environmentally friendly oxidative cleavage of tetrahydrofuran-2-methanols to the corresponding γ-lactones using a catalytic amount of 2-iodo-N-isopropylbenzamide has been developed. The reaction of various tetrahydrofuran-2-methanols with the catalyst in the presence of Oxone (2 KHSO5·KHSO4·K2SO4) as a co-oxidant in DMF at room temperature successfully affords the corresponding lactones in good to high yields, and recovery of the catalyst is readily accomplished using a reductive work-up. This method is notable because it enables the transformation of tetrahydrofuran-2-methanols to γ-lactones under mild conditions without the use of any toxic heavy metals.
- Yakura, Takayuki,Horiuchi, Yuto,Nishimura, Yushi,Yamada, Akihiro,Nambu, Hisanori,Fujiwara, Tomoya
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supporting information
p. 869 - 873
(2016/04/05)
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- Gas-phase fragmentation of γ-lactone derivatives by electrospray ionization tandem mass spectrometry
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Fragmentation reactions of β-hydroxymethyl-, β-acetoxymethyl- and β-benzyloxymethyl-butenolides and the corresponding γ-butyrolactones were investigated by electrospray ionization tandem mass spectrometry (ESI-MS/MS) using collision-induced dissociation (CID). This study revealed that loss of H2O [M+H-18]+ is the main fragmentation process for β-hydroxymethylbutenolide (1) and β-hydroxymethyl-γ- butyrolactone (2). Loss of ketene ([M+H-42]+) is the major fragmentation process for protonated β-acetoxymethyl-γ-butyrolactone (4), but not for β-acetoxymethylbutenolide (3). The benzyl cation (m/z 91) is the major ion in the ESI-MS/MS spectra of β-benzyloxymethylbutenolide (5) and β-benzyloxymethyl-γ-butyrolactone (6). The different side chain at the β-position and the double bond presence afforded some product ions that can be important for the structural identification of each compound. The energetic aspects involved in the protonation and gas-phase fragmentation processes were interpreted on the basis of thermochemical data obtained by computational quantum chemistry. Copyright
- Crotti, Antonio E. M.,Bronze-Uhle, Erika S.,Nascimento, Paulo G. B. D.,Donate, Paulo M.,Galembeck, Sergio E.,Vessecchi, Ricardo,Lopes, Norberto P.
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experimental part
p. 1733 - 1741
(2010/08/04)
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- Comparing the stereoselective biooxidation of cyclobutanones by recombinant strains expressing bacterial baeyer - Villiger monooxygenases
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Microbial Baeyer - Villiger oxidation of representative prochiral ketones with a cyclobutanone structural motif was investigated using a collection of eight monooxygenases of different bacterial origin. This platform of enzymes is able to perform stereoselective biotransformations on an array of structurally diverse substrates. With several ketone precursors, biooxidations yielded enantiocomplementary butyrolactones as key intermediates for the synthesis of natural products and bioactive compounds. The microbial Baeyer - Villiger oxidation allows a facile and rapid entry to several compound classes in a desymmetrization reaction upon de novo generation of chirality.
- Rudroff, Florian,Rydz, Joanna,Ogink, Freek H.,Fink, Michael,Mihovilovic, Marko D.
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p. 1436 - 1444
(2008/09/17)
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- A new synthetic entry to furofuranoid lignans, methyl piperitol and fargesin
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An efficient and general process is described for the preparation ofthe unsymmetrically substituted diequatorial and axial-equatorial furofuran lignans, methyl piperitol and fargesin. The synthetic strategy is based on a stereoselective manner by nucleoph
- Yoda, Hidemi,Suzuki, Yuji,Matsuura, Daisuke,Takabe, Kunihiko
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p. 519 - 522
(2007/10/03)
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- Acetonyltriphenylphosphonium bromide in organic synthesis: A useful catalyst in the cyclotrimerization of aldehydes
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Acetonyltriphenylphosphonium bromide (ATPB) is a useful catalyst for the cyclotrimerization of the aliphatic aldehydes under solvent-free condition. The aldehydes tethered with a variety of functionality such as olefin, ether, ester, bromide, azide and diester could also be cyclotrimerized under the catalysis of ATPB.
- Hon, Yung-Son,Lee, Chia-Fu
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p. 6181 - 6188
(2007/10/03)
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- Electron deficient flavin as catalyst for baeyer-villiger reaction: Oxidation of cyclobutanones to γ-lactones using hydrogen peroxide
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The use of an electron deficient isoalloxazine derivative as coenzyme model for the Baeyer-Villiger oxidation is described. This allows, in the presence of hydrogen peroxide, the catalytic oxidation of cyclobutanones into the corresponding γ-lactones with good to excellent yields.
- Mazzini, Claudio
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p. 1161 - 1167
(2007/10/03)
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- Enantioselective Metal-catalyzed Baeyer-Villiger Oxidation of Cyclobutanones
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Optically active lactones are obtained by metal-catalyzed aerobic oxidation of prochiral cyclobutanones. Starting from 3-mono-substituted substrates lactones with moderate enantioselectivities (up to 47% ee) have been obtained. Kelly's tricyclic ketone 8
- Bolm, Carsten,Luong, T. Kim Khanh,Schlingloff, Gunther
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p. 1151 - 1152
(2007/10/03)
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