- The Synthesis of Chiral α-Aryl α-Hydroxy Carboxylic Acids via RuPHOX-Ru Catalyzed Asymmetric Hydrogenation
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A ruthenocenyl phosphino-oxazoline-ruthenium complex (RuPHOX?Ru) catalyzed asymmetric hydrogenation of α-aryl keto acids has been successfully developed, affording the corresponding chiral α-aryl α-hydroxy carboxylic acids in high yields and with up to 97% ee. The reaction could be performed on a gram scale with a relatively low catalyst loading (up to 5000 S/C) and the resulting products can be transformed to several chiral building blocks, biologically active compounds and chiral drugs. (Figure presented.).
- Guo, Huan,Li, Jing,Liu, Delong,Zhang, Wanbin
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p. 3665 - 3673
(2017/09/11)
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- Asymmetric hydrogenation reaction of alpha-ketoacids compound
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The invention relates to the technical field of organic chemistry, especially to an asymmetric hydrogenation reaction of an alpha-ketoacids compound. The asymmetric hydrogenation reaction comprises a scheme shown in the description. In the scheme, R1 is phenyl, substituted phenyl, naphthyl, substituted naphthyl, C1-C6 alkyl, or aralkyl; a substituent group is C1-C6 alkyl, C1-C6 alkoxy, or halogen; and the number of the substituent group is 1-3. In the scheme, M is a chiral spiro-pyridylamino phosphine ligand iridium complex having a structure shown in the description. In the structure, R is hydrogen, 3-methyl, 4-tBu, or 6-methyl.
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Paragraph 0031; 0032; 0033; 0037
(2016/10/10)
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- Resolving synthetic method for paramethoxymandelic acid
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The present invention relates to a resolving synthetic method for paramethoxymandelic acid. The method comprises the following steps of: by taking chiral alpha-phenylethylamine acid as a resolving agent, carrying out a salt forming reaction on the paramet
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- Direct asymmetric hydrogenation of α-keto acids by using the highly efficient chiral spiro iridium catalysts
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A new efficient and highly enantioselective direct asymmetric hydrogenation of α-keto acids employing the Ir/SpiroPAP catalyst under mild reaction conditions has been developed. This method might be feasible for the preparation of a series of chiral α-hydroxy acids on a large scale.
- Yan, Pu-Cha,Xie, Jian-Hua,Zhang, Xiang-Dong,Chen, Kang,Li, Yuan-Qiang,Zhou, Qi-Lin,Che, Da-Qing
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p. 15987 - 15990
(2015/02/19)
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- A new system for the reduction of 4-hydroxymandelic acids
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We describe a new reduction of 4-hydroxymandelic acids which is easy to perform with available, cheap and environmentally clean reagents.The reduction of these acids is an important method for the synthesis of (4-hydroxyphenyl)-acetic acids.The new reducing system is constituted of sodium bisulfite or dithionite in catalytic quantities and formic acid in slight excess. - Keywords: 4-hydroxymandelic acid; reduction; sodium bisulfite; sodium dithionite; formic acid
- Vallejos, Jean Claude,Legrand, Olivier,Christidis, Yani
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p. 101 - 104
(2007/10/03)
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