The Experts below are selected from a list of 360 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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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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axially chiral dicarboxylic acid catalyzed activation of quinone imine Ketals enantioselective arylation of enecarbamates
Journal of the American Chemical Society, 2013Co-Authors: Takuya Hashimoto, Hiroki Nakatsu, Yuka Takiguchi, Keiji MaruokaAbstract:The synthetic utility of quinone imine Ketals in the context of asymmetric catalysis was disclosed for the first time. By expanding the utility of chiral Bronsted acid catalysis to the electrophilic activation of quinone imine Ketals, we succeeded in the development of highly enantioselective arylation of encarbamates to give α-amino-β-aryl ethers wherein quinone imine Ketals act as functionalized aromatic ring surrogate. Further transformations of the products were also examined to establish procedures to provide chiral β-aryl amines and α-aryl esters.
Hanmin Huang - One of the best experts on this subject based on the ideXlab platform.
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silver catalyzed olefination of acetals and Ketals with diazoesters to β alkoxyacrylates
Organic Letters, 2018Co-Authors: Bo Qian, Hanmin HuangAbstract:The first silver-catalyzed reaction of acetals or Ketals with diazoesters leading to trisubstituted or tetrasubstituted β-alkoxyacrylates is now reported. A broad range of acetals and Ketals bearing different substituents is compatible with this protocol and thus provides an attractive approach for the synthesis of complex β-alkoxyacrylates. The power of this method was further demonstrated by the successful synthesis of picoxystrobin, which is one of the most popular agricultural fungicides commercialized by Dupont.
Takuya Hashimoto - One of the best experts on this subject based on the ideXlab platform.
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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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axially chiral dicarboxylic acid catalyzed activation of quinone imine Ketals enantioselective arylation of enecarbamates
Journal of the American Chemical Society, 2013Co-Authors: Takuya Hashimoto, Hiroki Nakatsu, Yuka Takiguchi, Keiji MaruokaAbstract:The synthetic utility of quinone imine Ketals in the context of asymmetric catalysis was disclosed for the first time. By expanding the utility of chiral Bronsted acid catalysis to the electrophilic activation of quinone imine Ketals, we succeeded in the development of highly enantioselective arylation of encarbamates to give α-amino-β-aryl ethers wherein quinone imine Ketals act as functionalized aromatic ring surrogate. Further transformations of the products were also examined to establish procedures to provide chiral β-aryl amines and α-aryl esters.
Paul-serban Agachi - One of the best experts on this subject based on the ideXlab platform.
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Glycerol acetals and Ketals as possible diesel additives. A review of their synthesis protocols
Renewable & Sustainable Energy Reviews, 2016Co-Authors: Ancuţa Roxana Trifoi, Paul-serban AgachiAbstract:With the rapid development of the biodiesel industry all over the world, a large surplus of glycerol has been created, so economic uses of glycerol for value-added products are critical for the sustainability of the biodiesel industry. One of the main interests in recent years for glycerin utilization is its conversion in acetals and Ketals, with the potential to be used as fuel additives. Glycerol acetals and Ketals can be synthesized through the acid-catalyzed reaction of glycerol with aldehydes and ketones, respectively. This paper reviews different approaches and techniques used to obtain glycerol acetals and Ketals, regarding the reactor design, catalyst design and the effect of different parameters in the reaction system.
Sophie Thiebaudroux - One of the best experts on this subject based on the ideXlab platform.
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glycerol acetals and Ketals as bio based solvents positioning in hansen and cosmo rs spaces volatility and stability towards hydrolysis and autoxidation
Green Chemistry, 2015Co-Authors: Laurianne Moity, Adrien Benazzouz, Valerie Molinier, Veronique Nardellorataj, Mohammed Kamal Elmkaddem, Pascale De Caro, Sophie ThiebaudrouxAbstract:Four recently launched cyclic glycerol acetals or Ketals are evaluated as bio-based solvents. Three of them are industrially available and result from the condensation of glycerol with formaldehyde, acetone and isobutyl methyl ketone. The fourth is under development and is prepared by the reaction of glycerol with benzaldehyde under heterogeneous acidic catalysis. Their solvent properties are evaluated through Hansen and COSMO-RS (COnductor-like Screening MOdel for Real Solvents) approaches, in comparison with traditional petrochemical solvents. Dioxolane- and dioxane-type isomers have close solubility parameters; however the nature of the starting aldehyde/ketone significantly impacts the solvency properties. The stability to hydrolysis depends heavily on both the aldehyde/ketone part and on the size of the ring. In acidic medium, acetals are found to be more stable than Ketals and glycerol-based Ketals are more stable than ethylene glycol-based Ketals. In the case of benzaldehyde glycerol acetal, it is shown that the 6-membered ring isomer (dioxane-type) is approximately 8 times more stable than the 5-membered ring counterpart (dioxolane-type) at low pH. Stability towards autoxidation by O2 is high for formaldehyde and acetone-derived acetals and drops for the other two compounds. Glycerol acetals and Ketals are promising potential alternatives to some harmful solvents such as glycol ethers and aniline.
