21003-57-6Relevant articles and documents
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.
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
A hydrogen borrowing annulation strategy for the stereocontrolled synthesis of saturated aza-heterocycles
Armstrong, Roly J.,Chamberlain, Anna E. R.,Donohoe, Timothy J.,Paterson, Kieran J.,Twin, Heather C.
supporting information, p. 3563 - 3566 (2020/04/03)
An iridium catalyzed method for the synthesis of saturated aza-heterocycles from amines and diols is reported. A wide range of substituted heterocycles can be obtained using this approach including products bearing substituents at the C2, C3 and C4 positions. Employing water as the solvent, enantiopure diols could undergo annulation with minimal racemization, enabling the synthesis of valuable enantioenriched C3 and C4-substituted saturated aza-heterocycles.
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
Hydroboration Catalyzed by 1,2,4,3-Triazaphospholenes
Tien, Chieh-Hung,Adams, Matt R.,Ferguson, Michael J.,Johnson, Erin R.,Speed, Alexander W. H.
supporting information, p. 5565 - 5568 (2017/10/25)
The synthesis and study of the catalytic activity of 1,2,4,3-triazaphospholenes (TAPs) is reported. TAPs represent a more modular scaffold than previously reported diazaphospholenes. TAP halides were shown to catalyze the 1,2 hydroboration of 19 imines, and three α,β unsaturated aldehydes with pinacolborane, including examples that did not undergo hydroboration by previously reported diazaphospholene systems. DFT calculations support a mechanism where a triazaphospholene cation interacts with the substrate, a mechanism distinct from diazaphospholene catalyzed hydroborations.
Catalytic Asymmetric Reductive Condensation of N–H Imines: Synthesis of C2-Symmetric Secondary Amines
Wakchaure, Vijay N.,List, Benjamin
supporting information, p. 15775 - 15778 (2016/12/16)
A highly diastereoselective and enantioselective Br?nsted acid catalyzed reductive condensation of N?H imines was developed. This reaction is catalyzed by a chiral disulfonimide (DSI), uses Hantzsch esters as a hydrogen source, and delivers useful C2-symmetric secondary amines.
Phosphoramidite Ligands Based on Simple 1,2-Diols: Synthesis, Use in Copper-Catalyzed Asymmetric Additions, and Achirotopic Stereogenic Phosphorus Centres
Mistry, Nisha,Fletcher, Stephen P.
supporting information, p. 2489 - 2496 (2016/08/16)
Phosphoramidite ligands are widely used in catalysis and normally constructed from large C2-symmetrical diols such as BINOL or TADDOL. We report here on new ligands based on a set of simple diols that had been previously overlooked. Ligands based on (S,S)-trans-cyclohexanediol and (R,R)-(+)-1,2-diphenyl-1,2-ethanediol, in combination with both chiral and achiral amines, were tested in 3 different copper-catalyzed asymmetric reactions and up to 89% ee was observed. A different ligand gave the best results in each reaction examined. Using meso-cis-cyclohexanediol and meso-cis-diphenyl-1,2-ethanediol with a chiral non-racemic amine gave diastereomeric ligands bearing achirotopic stereogenic phosphorus atoms which were characterized with the assistance of X-ray crystallography and variable temperature NMR studies. This work provides a new set of ligands that may be useful in some asymmetric reactions when phosphoramidites based on BINOL and TADDOL are ineffective. We also identify a novel stereochemical feature of phosphoramidites that may be useful in asymmetric catalysis and ligand design. (Figure presented.).
