450-62-4Relevant articles and documents
Method for selective catalytic hydrogenation of aromatic heterocyclic compounds in non-hydrogen participation manner
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Paragraph 0025-0029; 0105-0109, (2021/08/19)
The invention discloses a method for selective catalytic hydrogenation of aromatic heterocyclic compounds in a non-hydrogen participation manner. The method comprises the following steps: by taking 1, 5-cyclooctadiene iridium chloride dimer as a catalyst and phenylsilane as a hydrogen source, carrying out stirring reaction under mild conditions without adding a ligand, namely catalytically hydrogenating the aromatic heterocyclic compounds to obtain hydrogenated products of the aromatic heterocyclic compounds. The method has the advantages of low cost, mild reaction conditions, high selectivity and the like, and special equipment such as a high-pressure kettle and the like and high-temperature conditions which are required when hydrogen is used are avoided.
Ni0/Niδ+ Synergistic Catalysis on a Nanosized Ni Surface for Simultaneous Formation of C-C and C-N Bonds
Zhang, Jian,An, Zhe,Zhu, Yanru,Shu, Xin,Song, Hongyan,Jiang, Yitao,Wang, Wenlong,Xiang, Xu,Xu, Linlin,He, Jing
, p. 11438 - 11446 (2019/11/21)
Simultaneous formation of C-C/C-N bonds provides insight into the bottom-up synthesis of N-heterocycles. This work reports Ni0/Niδ+ synergistic catalysis on the surface of Ni nanoparticles for the highly efficient one-pot formation of C-C/C-N bonds, affording 1,2,3,4-tetrahydroquinoline and its derivatives from 2-amino benzyl alcohol and ethanol without any addition of liquor base or external hydrogen. Ni0/Niδ+ synergistic catalysis has been achieved by regulating the Ni particle size or activating the Ni surface with O2. In the dehydrogenation of -CH2-OH to -CH=O, the formation of C==C and C=N bonds via concurrent cross-condensation, and the transformation of C=C/C=N to C-C/C-N via hydrogen transfer, ethanol dehydrogenation has been found to be the rate-determining step. Reducing the Ni particle size effectively increases the number of surface Niδ+ sites, which accelerates catalytic dehydrogenation through synergistic catalysis between surface Niδ+ and Ni0 sites. The number of surface Niδ+ sites can be further increased by appropriately activating the Ni surface with O2
Homogeneous Hydrogenation with a Cobalt/Tetraphosphine Catalyst: A Superior Hydride Donor for Polar Double Bonds and N-Heteroarenes
Duan, Ya-Nan,Du, Xiaoyong,Cui, Zhikai,Zeng, Yiqun,Liu, Yufeng,Yang, Tilong,Wen, Jialin,Zhang, Xumu
supporting information, p. 20424 - 20433 (2019/12/27)
The development of catalysts based on earth abundant metals in place of noble metals is becoming a central topic of catalysis. We herein report a cobalt/tetraphosphine complex-catalyzed homogeneous hydrogenation of polar unsaturated compounds using an air- and moisture-stable and scalable precatalyst. By activation with potassium hydroxide, this cobalt system shows both high efficiency (up to 24 000 TON and 12 000 h-1 TOF) and excellent chemoselectivities with various aldehydes, ketones, imines, and even N-heteroarenes. The preference for 1,2-reduction over 1,4-reduction makes this method an efficient way to prepare allylic alcohols and amines. Meanwhile, efficient hydrogenation of the challenging N-heteroarenes is also furnished with excellent functional group tolerance. Mechanistic studies and control experiments demonstrated that a CoIH complex functions as a strong hydride donor in the catalytic cycle. Each cobalt intermediate on the catalytic cycle was characterized, and a plausible outer-sphere mechanism was proposed. Noteworthy, external inorganic base plays multiple roles in this reaction and functions in almost every step of the catalytic cycle.
Gold Particles Supported on Amino-Functionalized Silica Catalyze Transfer Hydrogenation of N-Heterocyclic Compounds
Vilhanová, Beáta,van Bokhoven, Jeroen A.,Ranocchiari, Marco
supporting information, p. 677 - 686 (2017/02/23)
In this work we demonstrate that exceptionally small gold particles (d=0.6±0.2 nm) supported on amino-functionalized mesoporous silicate SBA-15 are highly active in transfer hydrogenation of structurally diverse unsaturated N-heterocyclic compounds. The heterocyclic ring is reduced selectively. The gold particles aggregate to a diameter of 4–5 nm in the presence of formic acid/triethylamine (hydrogen donor) during the first catalytic run. In subsequent cycles the nanoparticles maintain their size, yielding a very stable catalytic system that was recycled more than five times. In contrast, analogous SBA catalysts featuring larger (～5–35 nm) gold particles are not active. Excess formic acid also leads to the formation of formamide derivatives of the products of hydrogenation, which can be deformylated quantitatively. Fifteen structurally different substrates, including the scaffolds of quinoline, isoquinoline, quinoxaline, acridine, phenanthroline, quinazoline, and phenanthridine are hydrogenated and deformylated to give the amine products in >90% overall yield. Deuterium labeling experiments indicate that 1,2-addition with subsequent disproportionation of the formed intermediate is the preferred reaction path over the 1,4-addition one, suggesting the participation of a gold hydride species. (Figure presented.).
Iron-catalysed sequential reaction towards α-aminonitriles from secondary amines, primary alcohols and trimethylsilyl cyanide
Shen, Hang,Hu, Liangzhen,Liu, Qing,Hussain, Muhammad Ijaz,Pan, Jing,Huang, Mingming,Xiong, Yan
supporting information, p. 2776 - 2779 (2016/02/19)
We have developed a one-pot iron-catalysed sequential reaction of secondary amines with primary alcohols, trimethylsilyl cyanide and TBHP under mild reaction conditions to give the corresponding α-aminonitriles.
