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Yong Tang - One of the best experts on this subject based on the ideXlab platform.
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a highly efficient and enantioselective intramolecular Cannizzaro Reaction under tox cu ii catalysis
Journal of the American Chemical Society, 2013Co-Authors: Pan Wang, Wenjie Tao, Xiuli Sun, Saihu Liao, Yong TangAbstract:An asymmetric intramolecular Cannizzaro Reaction of aryl and alkyl glyoxals with alcohols has been realized with an unprecedented high level of enantioselectivity, on the basis of a newly developed congested TOX ligand and a gradual liberation protocol of active glyoxals from glyoxal monohydrates. Preliminary results suggested a mechanism of enantioselective addition of alcohols to glyoxals contributing most to the stereoselectivity, other than by the dynamic kinetic resolution of hemiacetal intermediates.
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A Highly Efficient and Enantioselective Intramolecular Cannizzaro Reaction under TOX/Cu(II) Catalysis
2013Co-Authors: Pan Wang, Wenjie Tao, Xiuli Sun, Saihu Liao, Yong TangAbstract:An asymmetric intramolecular Cannizzaro Reaction of aryl and alkyl glyoxals with alcohols has been realized with an unprecedented high level of enantioselectivity, on the basis of a newly developed congested TOX ligand and a gradual liberation protocol of active glyoxals from glyoxal monohydrates. Preliminary results suggested a mechanism of enantioselective addition of alcohols to glyoxals contributing most to the stereoselectivity, other than by the dynamic kinetic resolution of hemiacetal intermediates
Christian Bruckner - One of the best experts on this subject based on the ideXlab platform.
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oxazolochlorins 2 intramolecular Cannizzaro Reaction of meso tetraphenylsecochlorin bisaldehyde
Journal of Organic Chemistry, 2009Co-Authors: Joshua Akhigbe, Claudia Ryppa, Matthias Zeller, Christian BrucknerAbstract:Using mildly basic Reaction conditions, the periodate-induced diol cleavage of meso-tetraphenyl-2,3-diolchlorin allows for the generation and isolation of the corresponding hitherto elusive free ba...
О. И. Маршалок - One of the best experts on this subject based on the ideXlab platform.
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QUANTUM-CHEMICAL STUDY OF THE MECHANISM OF DISPROPORTIONATION OF 2,5-DIETHYL-3,4-DIHYDRO-2 H -PYRAN-2-CARBALDEHYDE IN THE Cannizzaro Reaction
Chemistry of Heterocyclic Compounds, 2014Co-Authors: Я. П. Ковальский, О. И. Маршалок, Н. М. ВитрикушAbstract:The mechanism of the disproportionation of 2,5-diethyl-3,4-dihydro-2 H -pyran-2-carbaldehyde in the Cannizzaro Reaction in ethanol was studied by quantum-chemical modeling. The geometry was optimized by the semiempirical RM1 method in the unrestricted Hartree–Fock approximation, and the heats of formation of the reagents and transitional states were calculated. Two possible hydride transfer Reaction paths are presented: through the formation of a transition state with one-center interaction or through a transition state with two-center interaction. The theoretically calculated values of the thermodynamic parameters agree with the experimental values and confirm the hydride transfer mechanism. How to Cite Kovalskyi, Ya. P.; Marshalok, O. I.; Vytrykush, N. M.; Marshalok, G. A. Chem. Heterocycl. Compd. 2014 , 50 , 7. [ Khim. Geterotsikl. Soedin. 2014 , 11.] For this article in the English edition see DOI 10.1007/s10593-014-1440-4
Makoto Fushimi - One of the best experts on this subject based on the ideXlab platform.
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asymmetric intramolecular Cannizzaro Reaction of anhydrous phenylglyoxal
Journal of Fluorine Chemistry, 2008Co-Authors: Kazuaki Ishihara, Takayuki Yano, Makoto FushimiAbstract:Abstract The use of anhydrous phenylglyoxal provides a solution to the problem of low reactivity in the asymmetric intramolecular Cannizzaro Reaction with alcohols. Double asymmetric induction was achieved in the Reaction of anhydrous phenylglyoxal with d -(+)-menthol promoted by a (S,S)-t-BuBox·copper(II) hexafluoroantimonate complex.
G. A. Marshalok - One of the best experts on this subject based on the ideXlab platform.
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Quantum-Chemical Study of the Mechanism of Disproportionation of 2,5-Diethyl-3,4-Dihydro-2H-Pyran-2-Carbaldehyde in the Cannizzaro Reaction
Chemistry of Heterocyclic Compounds, 2014Co-Authors: Yaroslav Kovalskyi, O. I. Marshalok, N. M. Vytrykush, G. A. MarshalokAbstract:The mechanism of the disproportionation of 2,5-diethyl-3,4-dihydro-2 H -pyran-2-carbaldehyde in the Cannizzaro Reaction in ethanol was studied by quantum-chemical modeling. The geometry was optimized by the semiempirical RM1 method in the unrestricted Hartree–Fock approximation, and the heats of formation of the reagents and transitional states were calculated. Two possible hydride transfer Reaction paths are presented: through the formation of a transition state with one-center interaction or through a transition state with two-center interaction. The theoretically calculated values of the thermodynamic parameters agree with the experimental values and confirm the hydride transfer mechanism.
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JOINT OBTAINING OF 2,5-DIETHYL-3 ,4-DIHYDRO-2H-PYRAN-2- METHANOL AND SODIUM SALT OF 2,5-DIETHYL-3 ,4-DIHYDRO-2H- PYRAN-2-CARBOXYLIC ACID VIA Cannizzaro Reaction
2009Co-Authors: Natalya Karpyak, G. A. Marshalok, Yaroslav Kovalskyi, Maria FedevychAbstract:Kinetic regularities of joint obtaining of 2,5- diethyl-3,4-dihydro-2H-pyran-2-methanol and sodium salt of 2,5-diethyl-3 ,4-dihydro-2H-pyran-2-carboxylic acid have been investigated. Optimal synthesis conditions have been established and physico-chemical characteristics of the main products have been determined. carbaldehyde by molecular oxygen. The main identified products are acetonylacetone (~30 %), acetic acid (25 %), and formic acid (15 %). As regards the pyranic alcohols, 2,5-dimethyl-3,4- dihydro-2H-pyran-2-methanol is obtained by catalytic hydrogenation of 2,5-dimethyl-3,4-dihydro-2-formyl-2H- pyran with the yield of 62 % (3). The yield of 3,4-dihydro- 2H-pyran-2-methanol obtained by reduction of 3,4- dihydro-2-formyl-2H-pyran with lithiumaluminumhydride is 61 % (7) and 20 % - when it is obtained by Tishchenko Reaction (8). Sodium salt of 3,4-dihydro-2H-pyran-2-carboxylic acid is obtained by saponificatio n of 2-(3,4-dihydro-1,2- pyranyl)-methyl-3,4-dihydro-2H-pyran-2-carboxilate at the heating with small excess of NaOH 20 %-aqueous solution (9). The yield is 70 %. Sodium salt of 2,5-dimethyl-3,4- dihydro-2H-pyran-2-carboxylic acid is obtained in a similar way by saponificatio n of 2-carboxy-2,5-dimethyl-3,4- dihydro-2H-pyran (10). The yield is 40 %. However the best results (yield by all products is nearly 80 %) are obtained at joint synthesis of 2,5- dimethyl-3,4-dihydro-2H-pyran-2-methanol and sodium salt of 2,5-dimethyl- 3,4-dihydro-2H-pyran-2-carboxylic acid from metacrolein dimer via Cannizzaro Reaction (11). Data concerning sodium salts of pyranic acids of the following terms of acrolein homologous series are absent. Therefore the aim of the present work is the investigation of kinetic regularities of joint obtaining of 2,5-diethyl-3,4- dihydro-2H-pyran-2-methanol and sodium salt of 2,5- diethyl-3,4-dihydro-2H-pyran-2-carboxylic acid via Cannizzaro Reaction with the following choice of optimal synthesis conditions.
