The Experts below are selected from a list of 588 Experts worldwide ranked by ideXlab platform
Keiji Maruoka - One of the best experts on this subject based on the ideXlab platform.
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boronic acid catalyzed highly enantioselective aza michael additions of hydroxamic acid to Quinone Imine ketals
Journal of the American Chemical Society, 2015Co-Authors: Takuya Hashimoto, Alberto Osuna Galvez, Keiji MaruokaAbstract:Boronic acid is one of the most versatile organic molecules in chemistry. Its uses include organic reactions, molecular recognition, assembly, and even medicine. While boronic acid catalysis, which utilizes an inherent catalytic property, has become an important research objective, it still lags far behind other boronic acid chemistries. Here, we report our discovery of a new boronic acid catalysis that enables the aza-Michael addition of hydroxamic acid to Quinone Imine ketals. By using 3-borono-BINOL as a chiral boronic acid catalyst, this reaction could be implemented in a highly enantioselective manner, paving the way to densely functionalized cyclohexanes.
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catalytic asymmetric diels alder reaction of Quinone Imine ketals a site divergent approach
ChemInform, 2015Co-Authors: Takuya Hashimoto, Hiroki Nakatsu, Keiji MaruokaAbstract:The site selectivity in these asymmetric Quinone Diels—Alder reactions strongly depends on the structure of the axially chiral dicarboxylic acid catalyst.
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catalytic asymmetric diels alder reaction of Quinone Imine ketals a site divergent approach
Angewandte Chemie, 2015Co-Authors: Takuya Hashimoto, Hiroki Nakatsu, Keiji MaruokaAbstract:: The catalytic asymmetric Diels-Alder reaction of Quinone Imine ketals with diene carbamates catalyzed by axially chiral dicarboxylic acids is reported herein. A variety of primary and secondary alkyl-substituted Quinone derivatives which have not been applied in previous asymmetric Quinone Diels-Alder reactions could be employed using this method. More importantly, we succeeded in developing a strategy to divert the reaction site in unsymmetrical 3-alkyl Quinone Imine ketals from the inherently favored unsubstituted C=C bond to the disfavored alkyl-substituted C=C bond.
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Boronic Acid-Catalyzed, Highly Enantioselective Aza-Michael Additions of Hydroxamic Acid to Quinone Imine Ketals
2015Co-Authors: Takuya Hashimoto, Alberto Osuna Gálvez, Keiji MaruokaAbstract:Boronic acid is one of the most versatile organic molecules in chemistry. Its uses include organic reactions, molecular recognition, assembly, and even medicine. While boronic acid catalysis, which utilizes an inherent catalytic property, has become an important research objective, it still lags far behind other boronic acid chemistries. Here, we report our discovery of a new boronic acid catalysis that enables the aza-Michael addition of hydroxamic acid to Quinone Imine ketals. By using 3-borono-BINOL as a chiral boronic acid catalyst, this reaction could be implemented in a highly enantioselective manner, paving the way to densely functionalized cyclohexanes
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axially chiral dicarboxylic acid catalyzed activation of Quinone Imine ketals enantioselective arylation of enecarbamates
ChemInform, 2014Co-Authors: Takuya Hashimoto, Hiroki Nakatsu, Yuka Takiguchi, Keiji MaruokaAbstract:The first asymmetric organocatalyzed synthesis of α-amino-β-aryl ethers from quinine Imine ketals and enecarbamates is presented.
Yingchun Chen - One of the best experts on this subject based on the ideXlab platform.
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asymmetric diels alder and cascade reaction of Quinone Imine ketals and 2 4 dienals construction of chiral benzo de quinolone derivatives
ChemInform, 2016Co-Authors: Benxian Xiao, Yurong Chen, Yingchun ChenAbstract:Quinone Imine ketals and 2,4-dienals undergo asymmetric Diels—Alder reaction followed by aromatization and cyclization to give hemiaminal products such as (VIII) which are subsequently reduced by Et3SiH to give more stable compounds.
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asymmetric diels alder and cascade reaction of Quinone Imine ketals and 2 4 dienals construction of chiral benzo de quinolone derivatives
Advanced Synthesis & Catalysis, 2016Co-Authors: Benxian Xiao, Yurong Chen, Yingchun ChenAbstract:An asymmetric Diels–Alder cycloaddition reaction of Quinone Imine ketals and 2,4-dienals has been investigated via trienamine catalysis of a secondary chiral amine. A series of chiral tricyclic benzo[de]quinolone derivatives were efficiently constructed in moderate to good yields and with high to excellent enantioselectivity after a cascade aromatization/intramolecular hemiaminal formation sequence (up to 98% ee, >19:1 dr). The methodology and the useful product scaffolds could be further utilized in both synthetic and medicinal fields.
Takuya Hashimoto - One of the best experts on this subject based on the ideXlab platform.
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boronic acid catalyzed highly enantioselective aza michael additions of hydroxamic acid to Quinone Imine ketals
Journal of the American Chemical Society, 2015Co-Authors: Takuya Hashimoto, Alberto Osuna Galvez, Keiji MaruokaAbstract:Boronic acid is one of the most versatile organic molecules in chemistry. Its uses include organic reactions, molecular recognition, assembly, and even medicine. While boronic acid catalysis, which utilizes an inherent catalytic property, has become an important research objective, it still lags far behind other boronic acid chemistries. Here, we report our discovery of a new boronic acid catalysis that enables the aza-Michael addition of hydroxamic acid to Quinone Imine ketals. By using 3-borono-BINOL as a chiral boronic acid catalyst, this reaction could be implemented in a highly enantioselective manner, paving the way to densely functionalized cyclohexanes.
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catalytic asymmetric diels alder reaction of Quinone Imine ketals a site divergent approach
ChemInform, 2015Co-Authors: Takuya Hashimoto, Hiroki Nakatsu, Keiji MaruokaAbstract:The site selectivity in these asymmetric Quinone Diels—Alder reactions strongly depends on the structure of the axially chiral dicarboxylic acid catalyst.
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catalytic asymmetric diels alder reaction of Quinone Imine ketals a site divergent approach
Angewandte Chemie, 2015Co-Authors: Takuya Hashimoto, Hiroki Nakatsu, Keiji MaruokaAbstract:: The catalytic asymmetric Diels-Alder reaction of Quinone Imine ketals with diene carbamates catalyzed by axially chiral dicarboxylic acids is reported herein. A variety of primary and secondary alkyl-substituted Quinone derivatives which have not been applied in previous asymmetric Quinone Diels-Alder reactions could be employed using this method. More importantly, we succeeded in developing a strategy to divert the reaction site in unsymmetrical 3-alkyl Quinone Imine ketals from the inherently favored unsubstituted C=C bond to the disfavored alkyl-substituted C=C bond.
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Boronic Acid-Catalyzed, Highly Enantioselective Aza-Michael Additions of Hydroxamic Acid to Quinone Imine Ketals
2015Co-Authors: Takuya Hashimoto, Alberto Osuna Gálvez, Keiji MaruokaAbstract:Boronic acid is one of the most versatile organic molecules in chemistry. Its uses include organic reactions, molecular recognition, assembly, and even medicine. While boronic acid catalysis, which utilizes an inherent catalytic property, has become an important research objective, it still lags far behind other boronic acid chemistries. Here, we report our discovery of a new boronic acid catalysis that enables the aza-Michael addition of hydroxamic acid to Quinone Imine ketals. By using 3-borono-BINOL as a chiral boronic acid catalyst, this reaction could be implemented in a highly enantioselective manner, paving the way to densely functionalized cyclohexanes
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axially chiral dicarboxylic acid catalyzed activation of Quinone Imine ketals enantioselective arylation of enecarbamates
ChemInform, 2014Co-Authors: Takuya Hashimoto, Hiroki Nakatsu, Yuka Takiguchi, Keiji MaruokaAbstract:The first asymmetric organocatalyzed synthesis of α-amino-β-aryl ethers from quinine Imine ketals and enecarbamates is presented.
Uwe T Bornscheuer - One of the best experts on this subject based on the ideXlab platform.
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Glycine Oxidase Based High-Throughput Solid-Phase Assay for Substrate Profiling and Directed Evolution of (R)- and (S)‑Selective Amine Transaminases
2015Co-Authors: Martin S. Weiß, Ioannis V Pavlidis, Clare Vickers, Matthias Höhne, Uwe T BornscheuerAbstract:Transaminases represent one of the most important enzymes of the biocatalytic toolbox for chiral amine synthesis as they allow asymmetric synthesis with quantitative yields and high enantioselectivity. In order to enable substrate profiling of transaminases for acceptance of different amines, a glycine oxidase and horseradish peroxidase coupled assay was developed. Transaminase activity is detected upon transfer of an amine group from an amino donor substrate to glyoxylate, generating glycine, which is subsequently oxidized by glycine oxidase, releasing hydrogen peroxide in turn. Horseradish peroxidase uses the hydrogen peroxide to produce benzoQuinone, which forms a red Quinone Imine dye by a subsequent condensation reaction. As glycine does not carry a chiral center, both (R)- and (S)-selective transaminases accepting glyoxylate as amino acceptor are amenable to screening. The principle has been transferred to establish a high-throughput solid-phase assay which dramatically decreases the screening effort in directed evolution of transaminases, as only active variants are selected for further analysis
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glycine oxidase based high throughput solid phase assay for substrate profiling and directed evolution of r and s selective amine transaminases
Analytical Chemistry, 2014Co-Authors: Martin S Weis, Ioannis V Pavlidis, Clare Vickers, Matthias Hohne, Uwe T BornscheuerAbstract:Transaminases represent one of the most important enzymes of the biocatalytic toolbox for chiral amine synthesis as they allow asymmetric synthesis with quantitative yields and high enantioselectivity. In order to enable substrate profiling of transaminases for acceptance of different amines, a glycine oxidase and horseradish peroxidase coupled assay was developed. Transaminase activity is detected upon transfer of an amine group from an amino donor substrate to glyoxylate, generating glycine, which is subsequently oxidized by glycine oxidase, releasing hydrogen peroxide in turn. Horseradish peroxidase uses the hydrogen peroxide to produce benzoQuinone, which forms a red Quinone Imine dye by a subsequent condensation reaction. As glycine does not carry a chiral center, both (R)- and (S)-selective transaminases accepting glyoxylate as amino acceptor are amenable to screening. The principle has been transferred to establish a high-throughput solid-phase assay which dramatically decreases the screening effor...
Santosh B. Mhaske - One of the best experts on this subject based on the ideXlab platform.
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transition metal free regioselective one pot synthesis of aryl sulfones from sodium sulfinates via Quinone Imine ketal
Journal of Organic Chemistry, 2019Co-Authors: Priyanka Halder, Vivek T. Humne, Santosh B. MhaskeAbstract:A novel, efficient, and regioselective transition-metal-free one-pot synthesis of aryl sulfones via the reactive Quinone Imine ketal intermediate is demonstrated using easily accessible bench-stable sulfinate salts. A broad range of functionality on p-anisidine substrates as well as sulfinate salts was tolerated under mild reaction conditions to provide the corresponding aryl sulfones in good to excellent yields.
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Transition-Metal-Free Regioselective One-Pot Synthesis of Aryl Sulfones from Sodium Sulfinates via Quinone Imine Ketal
2019Co-Authors: Priyanka Halder, Vivek T. Humne, Santosh B. MhaskeAbstract:A novel, efficient, and regioselective transition-metal-free one-pot synthesis of aryl sulfones via the reactive Quinone Imine ketal intermediate is demonstrated using easily accessible bench-stable sulfinate salts. A broad range of functionality on p-anisidine substrates as well as sulfinate salts was tolerated under mild reaction conditions to provide the corresponding aryl sulfones in good to excellent yields
