21003-56-5Relevant academic research and scientific papers
Origin of 1, 3-induction in the addition of alkyl lithium to imines bearing an N-stereogenic center
Nancy,Ghosh, Soma,Singh, Nishan,Nanda, Gurmeet Kaur,Venugopalan,Bharatam, Prasad V.,Trehan, Sanjay
, p. 1420 - 1421 (2003)
The origin of diastereoselectivity in the addition of alkyl lithium to chiral Schiff bases has been investigated experimentally and theoretically and the formation of the major diastereomer can be explained from the energy minimized structure of the Schiff base in which the phenyl group has been found to orient in such a manner that it posed lesser steric hindrance to the incoming nucleophile as compared to the alkyl group.
An Iridium Catalytic System Compatible with Inorganic and Organic Nitrogen Sources for Dual Asymmetric Reductive Amination Reactions
Chang, Mingxin,Gao, Zhaofeng,Geng, Huiling,Huang, Haizhou,Liu, Jingwen
supporting information, p. 27307 - 27311 (2021/11/17)
Asymmetric reductive amination (ARA) is one of the most promising methods for the synthesis of chiral amines. Herein we report our efforts on merging two ARA reactions into a single-step transformation. Catalyzed by a complex formed from iridium and a steric hindered phosphoramidite, readily available and inexpensive aromatic ketones initially undergo the first ARA with ammonium acetate to afford primary amines, which serve as the amine sources for the second ARA, and finally provide the enantiopure C2-symmetric secondary amine products. The developed process competently enables the successive coupling of inorganic and organic nitrogen sources with ketones in the same reaction system. The Br?nsted acid additive plays multiple roles in this procedure: it accelerates the formation of imine intermediates, minimizes the inhibitory effect of N-containing species on the iridium catalyst, and reduces the primary amine side products.
Rapid Multialkylation of Aqueous Ammonia with Alcohols by Heterogeneous Iridium Catalyst under Simple Conditions
Yu, Han,Ma, Lin,Wada, Kenji,Kurihara, Ryohsuke,Feng, Qi,Uemura, Shinobu,Isoda, Kyosuke
, p. 3588 - 3593 (2021/07/02)
This paper reports the synthesis of tertiary and secondary amines from aqueous ammonia and benzylic alcohols by titania-supported iridium catalyst. It is a successful example of heterogeneous systems at moderate temperature without either additional solvent or high pressure. The catalytic system showed good tolerance to the atmosphere condition and performed rapidly to give tribenzylamine a yield of over 99 % within 6 hours in argon. The crystal structure of titania supports for iridium catalysts strongly affected their activity. The catalysis smoothly proceeded on larger scales. The catalyst could be easily reused and run at least for 5 cycles without significant loss of activity. The highly-dispersed iridium species of less than 2 nm in diameter would be responsible for the excellent catalytic activity. This catalyst is well applicable in multialkylation of aqueous ammonia with various primary and secondary benzylic alcohols.
Method for synthesizing chiral phosphite ligand based on R - 2 - phenylethylamine
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, (2021/10/27)
The invention discloses a method for synthesizing chiral phosphite ligand based on R - 2 -phenylethylamine. To the method, R - 2 -phenylethylamine is reacted with acetophenone to obtain the imine intermediate, and then is mixed with H. 2 Under
Scalable preparation of stable and reusable silica supported palladium nanoparticles as catalysts for N-alkylation of amines with alcohols
Alshammari, Ahmad S.,Natte, Kishore,Kalevaru, Narayana V.,Bagabas, Abdulaziz,Jagadeesh, Rajenahally V.
, p. 141 - 149 (2020/01/06)
The development of nanoparticles-based heterogeneous catalysts continues to be of scientific and industrial interest for the advancement of sustainable chemical processes. Notably, up-scaling the production of catalysts to sustain unique structural features, activities and selectivities is highly important and remains challenging. Herein, we report the expedient synthesis of Pd-nanoparticles as amination catalysts by the reduction of simple palladium salt on commercial silica using molecular hydrogen. The resulting Pd-nanoparticles constitute stable and reusable catalysts for the synthesis of various N-alkyl amines using borrowing hydrogen technology without the use of any base or additive. By applying this Pd-based catalyst, functionalized and structurally diverse N-alkylated amines as well as some selected drug molecules were synthesized in good to excellent yields. Practical and synthetic utility of this Pd-based amination protocol has been demonstrated by upscaling catalyst preparation and amination reactions to several grams-scales as well as recycling of catalyst. Noteworthy, this Pd-catalyst preparation has been up-scaled to kilogram scale and catalysts prepared in both small (1 g) and large-scale (kg) exhibited similar structural features and activity.
Synthesis of 2-Arylisoindoline Derivatives Catalyzed by Reusable 1,2,4-Triazole Iridium on Mesoporous Silica through a Cascade Borrowing Hydrogen Strategy
Yao, Wei,Ge, Chenyang,Zhang, Yilin,Xia, Xiao-Feng,Wang, Long,Wang, Dawei
supporting information, p. 16099 - 16105 (2019/11/26)
Covalent attachment of a 1,2,4-triazole iridium complex to mesoporous MCM-41 generated a heterogeneous catalyst that was found to be effective in the synthesis of 2-aryl isoindolines, quinolines, cyclic amines, and symmetrical secondary amines through a cascade borrowing hydrogen strategy. Interestingly, the supported heterogeneous iridium catalyst prepared from the 1,2,4-triazole iridium complex and mesoporous MCM-41 exhibited high catalytic activity in the preparation of 2-aryl isoindoline derivatives and symmetrical secondary amines. The catalyst system is highly recyclable for at least five times. Besides the important effect of the triazole, iridium sites grafted on siliceous supports can act as multifunctional catalytic centers and thus greatly enhance the catalytic activity of the catalysts. Furthermore, mechanistic experiments revealed that the reaction is initiated by an initial alcohol dehydrogenation and promoted by an iridium hydride intermediate. Importantly, the direct detection of a diagnostic iridium hydride signal confirmed that the synthesis of 2-aryl isoindolines occurs by a borrowing hydrogen process. This work provides an efficient example of isoindolines synthesis through a borrowing hydrogen strategy.
One-Pot Synthesis of Symmetrical Tertiary and Secondary Amines from Carbonyl Compounds, Ammonium Carbonate and Carbon Monoxide as a Reductant
Muratov, Karim,Afanasyev, Oleg I.,Kuchuk, Ekaterina,Runikhina, Sofiya,Chusov, Denis
supporting information, p. 6557 - 6560 (2019/10/22)
Rh-catalyzed one-step synthesis of tertiary and secondary amines from aldehydes and ketones, ammonium carbonate serving as nitrogen source, and carbon monoxide as a reducing agent has been developed. Aliphatic and aromatic aldehydes lead to the corresponding tertiary symmetrical amines in 69–83 % yields. Aromatic and aliphatic ketones lead to the corresponding secondary symmetrical amines which were obtained in 62–79 % yields.
Preparation method of chiral amine compounds
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Paragraph 0018, (2018/09/13)
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.
B(C6F5)3-Catalyzed Asymmetric Reductive Amination of Ketones with Ammonia Borane
Pan, Zhentao,Shen, Leixin,Song, Dingguo,Xie, Zhen,Ling, Fei,Zhong, Weihui
, p. 11502 - 11509 (2018/09/25)
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.
Iron catalyzed diastereoselective hydrogenation of chiral imines
Brenna,Rossi,Cozzi,Benaglia
supporting information, p. 5685 - 5688 (2017/07/22)
Cyclopentadienone-based iron complexes were used for the first time to successfully catalyze the diastereoselective hydrogenation of enantiopure imines. Chiral amines, including valuable biologically active products, were obtained often as enantiomericall
