- A FACILE METHOD FOR THE ASYMMETRIC SYNTHESIS OF ENANTIOMERICALLY PURE 1-(2-FLUOROPHENYL)ETHYLAMINE
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A simple, two-step procedure for the synthesis of optically active (S)-1-(2-fluorophenyl)ethylamine (1) is described.Starting from commercially available 2-fluoroacetophenone (2), imination with (S)-1-phenylethylamine (3), followed by stereoselective hydrogenation over Raney-nickel gives the secondary amine 5a.Subsequent regioselective hydrogenolytic cleavage of homogenous 5a yields enantiomerically pure 1.
- Bringmann, G.,Geisler, J.-P.
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- Preparation method of chiral amine compounds
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The invention discloses a preparation method of chiral amine compounds. The preparation method of the chiral amine compounds specifically comprises the following steps: adding ketone compounds and chiral auxiliary (S)-a-phenylethylamine or (R)-a-phenylethylamine to an organic solvent to prepare an imine intermediate under the action of a large-steric-hindrance boron catalyst and a water removing agent; adding a reducing agent to the imine intermediate without separation and purification, and preparing the chiral amine compounds with a one-pot method. By calculation, the product yield is 81%-96%, and the highest de value can reach 99%. Compared with the prior art, the use amount of the large-steric-hindrance boron catalyst in the method can be reduced to 0.1 mol%, use of the equivalent metal catalyst is avoided from the source, and the method has the characteristics of being simple to operate, mild in reaction condition, wide in substrate applicability, environmental friendly and the like, and has better application value and potential economic and social benefits.
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Paragraph 0020
(2018/09/13)
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- B(C6F5)3-Catalyzed Asymmetric Reductive Amination of Ketones with Ammonia Borane
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The first example of metal-free B(C6F5)3-catalyzed asymmetric reduction amination of ketones with chiral α-methylbenzylamine (α-MBA) using ammonia borane as the reductant is reported. This one-pot method has a broad substrate scope and provides various chiral amines in 81-95% yield with 80-99% de. This protocol was further applied in the total synthesis of cinacalcet.
- Pan, Zhentao,Shen, Leixin,Song, Dingguo,Xie, Zhen,Ling, Fei,Zhong, Weihui
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p. 11502 - 11509
(2018/09/25)
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- Step-efficient access to chiral primary amines
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Routes to enantioenriched amines are outlined that employ reductive amination and carbanion addition methods. The strategies require either one or two reaction steps from prochiral carbonyl compounds for the synthesis of the corresponding chiral primary amines. Georg Thieme Verlag Stuttgart New York.
- Nugent, Thomas C.,Marinova, Sofiya M.
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p. 153 - 166
(2013/02/25)
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- Sequential reductive amination-hydrogenolysis: A one-pot synthesis of challenging chiral primary amines
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Difficult-to-access chiral primary amines were formed in good to high yield and ee using a rare example of a one-pot synthesis from prochiral ketones (sequential reductive amination-hydrogenloysis). As a highlight we also demonstrate a one-pot reductive amination-hydrogenolysis-reductive amination (five reactions) of ortho-methoxyacetophenone resulting in the chiral diamine 1-(2-methoxyphenyl)ethyl-(2-pyridylmethyl)-amine (4) (58% overall yield, >99% ee), a new organocatalyst for aqueous enantioselective aldol reactions. Copyright
- Nugent, Thomas C.,Negru, Daniela E.,El-Shazly, Mohamed,Hu, Dan,Sadiq, Abdul,Bibi, Ahtaram,Umar, M. Naveed
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supporting information; experimental part
p. 2085 - 2092
(2011/10/19)
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- Practical synthesis of optically active fluorine-substituted α-phenylethylamines by retardation of hydrogenolytic cleavage at benzylic position
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High regioselectivity in hydrogenolysis of bis(α-methylbenzyl)amines having a fluorine atom on aromatic ring results from retardation of hydrogenolytic cleavage at benzylic position of fluorine-substituted aromatic ring.
- Kanai, Masatomi,Yasumoto, Manabu,Kuriyama, Yokusu,Inomiya, Kenjin,Katsuhara, Yutaka,Higashiyama, Kimio,Ishii, Akihiro
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p. 1424 - 1425
(2007/10/03)
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