6776-19-8Relevant academic research and scientific papers
Fabrication of Ni3N nanorods anchored on N-doped carbon for selective semi-hydrogenation of alkynes
Shi, Xiaozhen,Wen, Xin,Nie, Shilin,Dong, Jie,Li, Jingde,Shi, Yongqing,Zhang, Huiling,Bai, Guoyi
, p. 22 - 30 (2019/12/26)
Nickel is a highly active catalyst for the semi-hydrogenation of alkynes. However, the low selectivity of the alkene product caused by the over-hydrogenation reaction on Ni has hindered its practical applications. In this work, we report a new nickel nitride (Ni3N)-catalyzed semi-hydrogenation of alkynes to the corresponding alkenes. The Ni3N nanorods were facilely fabricated via a direct pyrolysis of the solid mixture of nickel acetate tetrahydrate and melamine (Mlm). The Ni3N phase in the optimum catalyst (Ni3N/NC-6/5-550) is shown to be effective and stable in the semi-hydrogenation of alkynes, with a high yield and good selectivity for alkenes (Z/E ratios up to >99/1). Both terminal and internal alkynes bearing a broad scope of functional groups are readily converted into alkenes with good chemo- and stereoselectivity. Notably, it was found that the over-hydrogenation can be markedly suppressed even at high conversion of alkyne. Density functional theory (DFT) calculations reveal that the low interaction between the alkene product and the Ni3N might plays a critical role in the selectivity enhancement.
Diastereoselectivity in the boron aldol reaction of α-alkoxy and α,β-bis-alkoxy methyl ketones
Fernandes, Alessandra A. G.,Leonarczyk, Ives A.,Ferreira, Marco A. B.,Dias, Luiz Carlos
supporting information, p. 3167 - 3180 (2019/03/26)
In this work, using DFT calculations, we investigated the 1,4 and 1,5 asymmetric induction in boron enolate aldol reactions of α-alkoxy and α,β-bisalkoxy methyl ketones. We evaluated the steric influence of alkyl substituents at the α position and the stereoelectronic influence of the oxygen protecting groups at the α and β positions. Theoretical calculations revealed the origins of the 1,4 asymmetric induction in terms of the nature of the β-substituent. The synergistic effect between the α,β-syn and α,β-anti-bisalkoxy stereocenters was elucidated. In the presence of the β-alkoxy center, the reaction proceeds through the Goodman-Paton 1,5-stereoinduction model, experiencing a minor influence of the α-alkoxy center.
Monitoring Hydrogenation Reactions using Benchtop 2D NMR with Extraordinary Sensitivity and Spectral Resolution
Go?owicz, Dariusz,Kazimierczuk, Krzysztof,Urbańczyk, Mateusz,Ratajczyk, Tomasz
, p. 196 - 200 (2019/04/26)
Low-field benchtop nuclear magnetic resonance (BT-NMR) spectrometers with Halbach magnets are being increasingly used in science and industry as cost-efficient tools for the monitoring of chemical reactions, including hydrogenation. However, their use of
Selective Semihydrogenation of Alkynes Catalyzed by Pd Nanoparticles Immobilized on Heteroatom-Doped Hierarchical Porous Carbon Derived from Bamboo Shoots
Ji, Guijie,Duan, Yanan,Zhang, Shaochun,Fei, Benhua,Chen, Xiufang,Yang, Yong
, p. 3427 - 3434 (2017/09/15)
Highly dispersed palladium nanoparticles (Pd NPs) immobilized on heteroatom-doped hierarchical porous carbon supports (N,O-carbon) with large specific surface areas are synthesized by a wet chemical reduction method. The N,O-carbon derived from naturally abundant bamboo shoots is fabricated by a tandem hydrothermal–carbonization process without assistance of any templates, chemical activation reagents, or exogenous N or O sources in a simple and ecofriendly manner. The prepared Pd/N,O-carbon catalyst shows extremely high activity and excellent chemoselectivity for semihydrogenation of a broad range of alkynes to versatile and valuable alkenes under ambient conditions. The catalyst can be readily recovered for successive reuse with negligible loss in activity and selectivity, and is also applicable for practical gram-scale reactions.
Ru(ii)-Pheox-catalyzed Si-H insertion reaction: construction of enantioenriched carbon and silicon centers
Nakagawa, Yoko,Chanthamath, Soda,Fujisawa, Ikuhide,Shibatomi, Kazutaka,Iwasa, Seiji
supporting information, p. 3753 - 3756 (2017/04/03)
We established a highly enantioselective Si-H insertion reaction to construct chiral centers at the carbon and silicon atoms, using a Ru(ii)-pheox catalyst. The catalytic asymmetric Si-H insertion reaction of α-methyl-α-diazoesters proceeded smoothly with excellent stereoinduction at both the neighboring carbon and silicon atoms (up to 99% yield and 99% ee).
Design of Core-Pd/Shell-Ag Nanocomposite Catalyst for Selective Semihydrogenation of Alkynes
Mitsudome, Takato,Urayama, Teppei,Yamazaki, Kenji,Maehara, Yosuke,Yamasaki, Jun,Gohara, Kazutoshi,Maeno, Zen,Mizugaki, Tomoo,Jitsukawa, Koichiro,Kaneda, Kiyotomi
supporting information, p. 666 - 670 (2016/02/18)
We designed core-Pd/shell-Ag nanocomposite catalyst (Pd@Ag) for highly selective semihydrogenation of alkynes. The construction of the core-shell nanocomposite enables a significant improvement in the low activity of Ag NPs for the selective semihydrogenation of alkynes because hydrogen is supplied from the core-Pd NPs to the shell-Ag NPs in a synergistic manner. Simultaneously, coating the core-Pd NPs with shell-Ag NPs results in efficient suppression of overhydrogenation of alkenes by the Pd NPs. This complementary action of core-Pd and shell-Ag provides high chemoselectivity toward a wide range of alkenes with high Z-selectivity under mild reaction conditions (room temperature and 1 atm H2). Moreover, Pd@Ag can be easily separated from the reaction mixture and is reusable without loss of catalytic activity or selectivity.
Rhodium(II)-catalyzed c-h functionalization of electron-deficient methyl groups
Fu, Liangbing,Guptill, David M.,Davies, Huw M. L.
supporting information, p. 5761 - 5764 (2016/06/08)
Enantioselective C-H functionalization of relatively electron-deficient methyl sites was achieved with the combination of 2,2,2-trichloroethyl aryldiazoacetates and tetrakis(triarylcyclopropanecarboxylate) dirhodium catalysts. The substrate scope of the transformation was relatively broad, and C-H functionalization products were furnished with excellent levels of enantioselectivity. As a strategic reaction, crotonate derivatives give 1,6-dicarbonyl compounds, which are useful for further diversification.
NOVEL TRICYCLIC COMPOUNDS
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Paragraph 0533-0535, (2013/03/28)
The invention provides compounds of Formula (I) pharmaceutically acceptable salts, pro-drugs, biologically active metabolites, stereoisomers and isomers thereof wherein the variable are defined herein. The compounds of the invention are useful for treating immunological and oncological conditions.
Highly enantioselective cyclopropenation reaction of 1-alkynes with α-alkyl-α-diazoesters catalyzed by dirhodium(II) carboxylates
Goto, Takayuki,Takeda, Koji,Shimada, Naoyuki,Nambu, Hisanori,Anada, Masahiro,Shiro, Motoo,Ando, Kaori,Hashimoto, Shunichi
supporting information; experimental part, p. 6803 - 6808 (2011/08/21)
Two rhodium(II) ions work together: [Rh2(S-tbpttl)4] is an exceptionally effective catalyst for enantioselective cyclopropenation reactions of 1-alkynes with α-alkyl-α-diazoacetates (see scheme). Cyclopropenation is preferred over alkene formation through a 1,2-hydride shift. Copyright
Rh-catalyzed intermolecular cyclopropanation with α-alkyl-α- diazoesters: Catalyst-dependent chemo- and diastereoselectivity
Panne, Patricia,DeAngelis, Andrew,Fox, Joseph M.
body text, p. 2987 - 2989 (2009/04/18)
(Chemical Equation Presented) A Rh-catalyzed procedure for the cyclopropanation of alkenes with α-alkyl-α-diazoesters is described. With dirhodium tetraoctanoate, the predominant pathway is β-hydride elimination. While a number of sterically demanding carboxylate ligands serve to avoid β-hydride elimination, it was found that triphenylacetate (TPA) also imparts high diastereoselectivity.
