- Silver-catalyzed formal [3+2]-cycloaddition of α-trifluoromethylated methyl isocyanides: a facile stereoselective synthesis of CF3-substituted heterocycles
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An Ag-catalyzed formal [3+2]-cycloaddition of α-trifluoromethylated methyl isocyanides with polar double bonds has been developed for the facile access to trifluoromethylated oxazolines, imidazolines and pyrrolines under mild conditions. The practicality of this chemistry is demonstrated by the gram-scale synthesis of oxazolines with excellent yields and facile transformations of the formed oxazolines to trifluoromethylated β-amino alcohols in quantitative yields.
- Zhang, Xue,Wang, Xin,Gao, Yuelei,Xu, Xianxiu
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supporting information
p. 2427 - 2430
(2017/03/01)
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- MOF-derived cobalt nanoparticles catalyze a general synthesis of amines
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The development of base metal catalysts for the synthesis of pharmaceutically relevant compounds remains an important goal of chemical research. Here, we report that cobalt nanoparticles encapsulated by a graphitic shell are broadly effective reductive amination catalysts. Their convenient and practical preparation entailed template assembly of cobaltdiamine- dicarboxylic acid metal organic frameworks on carbon and subsequent pyrolysis under inert atmosphere.The resulting stable and reusable catalysts were active for synthesis of primary, secondary, tertiary, and N-methylamines (more than 140 examples).The reaction couples easily accessible carbonyl compounds (aldehydes and ketones) with ammonia, amines, or nitro compounds, and molecular hydrogen under industrially viable and scalable conditions, offering cost-effective access to numerous amines, amino acid derivatives, and more complex drug targets.
- Jagadeesh, Rajenahally V.,Murugesan, Kathiravan,Alshammari, Ahmad S.,Neumann, Helfried,Pohl, Marga-Martina,Radnik, J?rg,Beller, Matthias
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p. 326 - 332
(2017/09/28)
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- Economical and practical strategies for synthesis of α-trifluoromethylated amines
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A powerful approach to synthesize α-trifluoromethylated amines has been developed. The method is operationally simple, broad in substrate scope and amenable to scale-up using trifluoroacetic anhydride. Meanwhile, the strategy not only provided a versatile approach to synthesize α-trifluoromethylated amines but also provides a new method for exploring the new reactivity of trifluoroacetic anhydride.
- Jiang,Cheng,Yuan
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p. 2406 - 2408
(2016/05/19)
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- Stereoselective transformations of α-trifluoromethylated ketoximes to optically active amines by enzyme-nanometal cocatalysis: Synthesis of (s)-inhibitor of phenylethanolamine n-methyltransferase
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One-pot cascade synthesis of optically active α-trifluoromethylated amines directly from ketoximes was accomplished with the use of Candida antarctica lipase B and catalysts prepared by atomic layer deposition (ALD). Compared to the commercial palladium catalyst, the ALD-prepared catalysts showed much higher activity and afforded various α-trifluoromethylated amides in good yields and with high enantioselectivity. One of the enantiopure amides was further hydrolyzed into the corresponding amine, which was treated as a crucial starting material for total synthesis of (S)-inhibitor of phenylethanolamine N-methyltransferase without loss of chiral information.
- Cheng, Guilin,Wu, Qi,Shang, Zeyu,Liang, Xinhua,Lin, Xianfu
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p. 2129 - 2133
(2014/08/05)
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- Chemoenzymatic dynamic kinetic resolution of α-trifluoromethylated amines: Influence of substitutions on the reversed stereoselectivity
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Enzymatic resolution of α-trifluoromethylated amines via kinetic resolution (KR), dynamic kinetic resolution (DKR) employing CALB-Pd/Al 2O3, and a one-pot sequential process of KR/DKR/KR was investigated comparatively for the first time. Although CALB-catalyzed KR of α-trifluoromethylated amines with substituents of methyl (1a), isopropyl (1c), phenyl (1d) and benzyl group (1e) can provide good stereoselectivity factors E from 31 to >200 respectively, DKR and sequential process of KR/DKR/KR possess better practical application potential because of the higher conversion (62%-84%) and the similar enantiomeric excesses (90%-99%). The enantiopreference and inversion for the α-trifluoromethylated amines displayed by CALB were observed and explained by docking modes. Namely, for 1,1,1-trifluoro-2-propylamine (1a), the product amide with R-configuration was obtained, and the enantiopreference was converted to S for the amines (1b-1e) with substituents larger than methyl group. The catalysts recycle, and scale-up experiments were demonstrated successfully. All these results indicated the high efficiency and green feature of this enzymatic process, and its application significance.
- Cheng, Guilin,Xia, Bo,Wu, Qi,Lin, Xianfu
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p. 9820 - 9828
(2013/09/02)
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- Synthesis and application of benzyl-TMS derivatives as bench stable benzyl anion equivalents
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The regioselective benzylic metalation of toluenes using BuLi/KO tBu/TMP(H) (LiNK metalation conditions) and subsequent transmetalation to Si by reaction with TMSCl provides a general one-pot procedure for the synthesis of substituted benzyltrimethylsilanes. ArCH 2Si(Me)3 derivatives are bench stable reagents yet can serve as benzyl anion equivalents under mild reaction conditions. Following activation with fluoride they can successfully participate in a wide range of additions to both non-enolizable and enolizable carbonyls. In addition, their use in the synthesis of isochromanones and trifluoromethylated amines is illustrated. The broad synthetic scope and mild practical conditions of use for ArCH2Si(Me)3 reagents demonstrate their general potential as benzyl anion equivalents.
- Das, Manas,O'Shea, Donal F.
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p. 6448 - 6460
(2013/07/26)
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- A new strategy for the synthesis of optically pure β-fluoroalkyl β-amino acid derivatives
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(Chemical Equation Presented) The first general approach for the diastereoselective formation of a variety of optically pure anti/β- fluoroalkyl β-amino acid derivatives is described. The process relies on the stereocontrolled reaction, mediated by a remo
- Fustero, Santos,Pozo, Carlos Del,Catalan, Silvia,Aleman, Jose,Parra, Alejandro,Marcos, Vanesa,Ruano, Jose Luis Garcia
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supporting information; experimental part
p. 641 - 644
(2009/08/14)
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- Synthesis and evaluation of 3-trifluoromethyl-7-substituted-1,2,3,4- tetrahydroisoquinolines as selective inhibitors of phenylethanolamine N- methyltransferase versus the α2-adrenoceptor
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A series of 3-trifluoromethyl-1,2,3,4-tetrahydroisoquinolines was synthesized and evaluated as inhibitors of phenylethanolamine N- methyltransferase (PNMT) and as inhibitors of the binding of clonidine at the α2-adrenoceptor. These compounds we
- Grunewald, Gary L.,Caldwell, Timothy M.,Li, Qifang,Criscione, Kevin R.
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p. 3315 - 3323
(2007/10/03)
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- A practical route to fluoroalkyl- and fluoroarylamines by base-catalyzed [1,3]-proton shift reaction
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The base-catalyzed [1,3]-proton shift reaction is shown to be an efficient general approach to fluoroalkyl and fluoroaryl amines starting from appropriate carbonyl compounds and benzylamine.
- Soloshonok,Soloshonok, Vadim A.,Kirilenko,Kirilenko, Alexander G.,Kukhar,Kukhar, Valery P.,Resnati,Resnati, Giuseppe
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p. 3119 - 3122
(2007/10/02)
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