- Resolution of 1-arylalkylamines with 6-(1,2:3,4-di-O-isopropylidene- α-D-galactopyranosyl)hydrogen phthalate
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The resolving ability of a new acidic resolving agent, the hydrogen phthalate of 1,2:3,4-di-O-isopropylidene-α-D-galactopyranose 1, against various 1-arylalkylamines 2a-k is described. Treatment of 1 with amines 2a-f to obtain diastereomeric salts 1·(S)2a-f in 2-propanol allowing the corresponding (S)-amines 2a-f to be recovered in good yield and 61-89% ee. Recrystallization in dichloromethane/hexane, and regeneration gave the amines in enhanced enantiomeric purity (>98% ee). 1 resolved 1-phenylpropylamine 2f in high enantiomeric purity (99% ee) than 1-phenylethylamine 2g (11% ee) and o- and m-methoxy 2h-i, o-chloro-2j and p-fluoro-2k substituted 1-arylamines (11-19% ee). A possible chiral recognition mechanism based on the ability of 1 to exist in two conformations is described.
- Mereyala, Hari Babu,Fatima, Liyakat,Pola, Pallavi
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- Catalytic asymmetric oxidative carbonylation-induced kinetic resolution of sterically hindered benzylamines to chiral isoindolinones
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A highly enantioselective kinetic resolution of sterically hindered benzylamines has been achieved for the first time through transition-metal-catalyzed oxidative carbonylation, in which the new KR strategy offered a new approach to afford chiral isoindolinones (er up to 97?:?3) and the origin of chemoselectivity and stereoselectivity was confirmed by density functional theory (DFT) calculations.
- Mu, Qiu-Qi,Nie, Yi-Xue,Li, Hang,Bai, Xing-Feng,Liu, Xue-Wei,Xu, Zheng,Xu, Li-Wen
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supporting information
p. 1778 - 1781
(2021/02/27)
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- Ultra-small cobalt nanoparticles from molecularly-defined Co-salen complexes for catalytic synthesis of amines
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We report the synthesis of in situ generated cobalt nanoparticles from molecularly defined complexes as efficient and selective catalysts for reductive amination reactions. In the presence of ammonia and hydrogen, cobalt-salen complexes such as cobalt(ii)-N,N′-bis(salicylidene)-1,2-phenylenediamine produce ultra-small (2-4 nm) cobalt-nanoparticles embedded in a carbon-nitrogen framework. The resulting materials constitute stable, reusable and magnetically separable catalysts, which enable the synthesis of linear and branched benzylic, heterocyclic and aliphatic primary amines from carbonyl compounds and ammonia. The isolated nanoparticles also represent excellent catalysts for the synthesis of primary, secondary as well as tertiary amines including biologically relevant N-methyl amines.
- Beller, Matthias,Chandrashekhar, Vishwas G.,Gawande, Manoj B.,Jagadeesh, Rajenahally V.,Kalevaru, Narayana V.,Kamer, Paul C. J.,Senthamarai, Thirusangumurugan,Zbo?il, Radek
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p. 2973 - 2981
(2020/03/27)
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- Method for synthesizing chiral amine compound
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The present invention provides a method for synthesizing a chiral amine compound. The method comprises the following steps: (1) reacting a compound of formula I with t-butylsulfonamide in the presenceof a catalyst to obtain a compound having a structure represented by formula II; 2) reacting the compound of the formula II in a hydrogen atmosphere in the presence of an iridium catalyst and a ligand to obtain a compound of formula III; and (3) carrying out a t-butylsulfonyl group removal reaction on the compound of the formula III to obtain the chiral amine compound. The method constructs the structure of sulfonamide by a keto carbonylgroup, and synthesizes the chiral amine compound with the aralkylamine structure by an asymmetric catalytic hydrogenation reaction of the sulfonamide structure, the ee value is generally 80% or above, the highest ee value is 99% or above, the yield of each step reaction can reach 90% or above, and the total yield is high.
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- Rh(III)-Catalyzed Coupling of N-Chloroimines with α-Diazo-α-phosphonoacetates for the Synthesis of 2 H-Isoindoles
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We report herein the first use of N-chloroimines as effective synthons for directed C-H functionalization. Rh(III)-catalyzed coupling of N-chloroimines with α-diazo-α-phosphonoacetates allows for efficient dechlorinative/dephosphonative access to 2H-isoindoles. Further deesterification under Ni(II) catalysis enables the complete elimination of reactivity-assisting groups and full exposure of reactivity of C3 and N2 ring atoms for attaching structurally distinct appendages.
- Qi, Bing,Li, Lei,Wang, Qi,Zhang, Wenjing,Fang, Lili,Zhu, Jin
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supporting information
p. 6860 - 6863
(2019/09/12)
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- Resolution of 1-arylalkylamines with 3-O-hydrogen phthalate glucofuranose derivatives: Role of steric bulk in a family of resolving agents
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The development of three new acidic resolving agents which are hydrogen phthalates of 1,2:5,6-di-O-isopropylidene-α-d-glucofuranose 1, 1,2:5,6-di-O-cyclohexylidene-α-d-glucofuranose 2 and 1,2-O- cyclohexylidene-5,6-O-diphenylmethylidene-α-d-glucofuranose 3 is shown for the resolution of 1-arylalkylamines 7a-k. The salts between 1, 2 and (RS)-1-arylalkylamines 7a-k selectively crystallize 1?(S) 7a-j and 2?(S) 7a-h salts, allowing us to recover the corresponding bases (S) 7a-j and (S) 7a-h, respectively, in good yield and enantiomeric excess (73-95% ee). Whereas, the salts between 3 and (RS)-1-arylalkylamines 7a-c,g-i,k selectively crystallize 3?(S)-7a-c,g-i salts to recover the corresponding bases (S)-7a-c,g-i in poor enantiomeric excess (4-35% ee). The difference between the resolving ability of 1 and 2 for 1-arylalkylamines 7a-h is very slight, but there is considerable difference compared to ortho-substituted 1-arylalkylamines 7i and 7j. The role of substituents on a family of resolving agents 1, 2 and 3 is also discussed to interpret their resolving ability.
- Mereyala, Hari Babu,Koduru, Sreenivasulu Reddy,Cheemalapati, Venkata Narasimhaji
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p. 259 - 267
(2007/10/03)
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- Synthesis and chiral recognition ability of O-phenyl ethylphosphonothioic acid with a conformationally flexible phenoxy group for CH/π interaction
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Enantiopure O-phenyl ethylphosphonothioic acid 1 was easily obtained by the enantioseparation of racemic 1, which was prepared from commercially available phosphorothioic trichloride in four steps. Enantiopure 1 was found to show an excellent chiral recognition ability for various 1-arylethylamine derivatives during the diastereomeric salt formation. In particular, enantiopure 1 was able to recognize the chirality of o- and m-substituted 1-arylethylamine derivatives, of which the chirality is generally difficult to establish by conventional resolving agents. X-ray crystallographic analyses of the less-soluble diastereomeric salts revealed that the conformation of the phenoxy group in enantiopure 1 could change in the diastereomeric salt crystals and that the excellent chiral recognition ability of enantiopure 1 resulted from the effective CH/π interaction of the phenoxy phenyl group.
- Kobayashi, Yuka,Maeda, Jin,Morisawa, Fumi,Saigo, Kazuhiko
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p. 967 - 974
(2007/10/03)
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- Process for preparing optically active amines and optically active carboxylic acids, and intermediates for preparation
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Disclosed is a process for preparing an optically active 1-aryl- or 2-aryl-alkylamines of formulas Ia, Ib and Ic with high optical purity and high yield. The process uses an optically active 1- or 2-naphthylglycolic acid of the general formula II as a resolving agent. Also disclosed is a process for praparing an optically active 1- or 2-naphthylglycolic acid of formula II using an optically active 1-aryl- or 2-aryl-alkylamines of formulas Ia, Ib and Ic as the resolving agents
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- A high-performance, tailor-made resolving agent: Remarkable enhancement of resolution ability by introducing a naphthyl group into the fundamental skeleton1
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A novel resolving agent, 2-naphthylglycolic acid (2-NGA), was designed for p-substituted 1-arylethylamines on the basis of the consideration that a rigid and large naphthyl group would be favorable for the close packing of supramolecular hydrogen-bond sheets formed between the carboxy groups of 2-NGA and the amino groups of p-substituted 1-arylethylamines. Racemic 2-NGA was readily available from commercially available raw materials, and both enantiopure forms could be obtained by simple diastereomeric resolution with enantiopure 1-phenyl-ethylamine. Thus-prepared enantiopure 2-NGA was found to have an excellent resolution ability not only for p-substituted 1-arylethylamines, but also for a wide variety of chiral primary amines. X-Ray crystallographic analyses of the less- and more-soluble diastereomeric salts revealed that this excellent resolution ability of 2-NGA arose from the formation of a supramolecular hydrogen-bond sheet with the primary amine, as we had expected, and also from the possible achievement of an infinite chain of CH... π interaction between its naphthyl group and the aromatic group of the amine, which was formed in the hydrophobic region of the supramolecular hydrogen-bond sheet.
- Kinbara, Kazushi,Harada, Yoshiko,Saigo, Kazuhiko
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p. 1339 - 1347
(2007/10/03)
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