2983-48-4Relevant academic research and scientific papers
Yolk-Shell-Mesostructured Silica-Supported Dual Molecular Catalyst for Enantioselective Tandem Reactions
Wu, Liang,Li, Yilong,Meng, Jingjing,Jin, Ronghua,Lin, Jingrong,Liu, Guohua
, p. 861 - 867 (2018)
Yolk-shell-mesostructured silica was used as a support in the development of an active-site-isolated bifunctional catalyst that can mediate a sequential organic transformation. Herein, through immobilization, the location of two catalytic species is controlled: a base functionality is anchored in the channels of the outer silica shell and a chiral ruthenium/diamine functionality is anchored on the inner silica yolk. The result is a yolk-shell-mesostructured silica-supported active-site-isolated dual molecule catalyst. Structural analysis through solid-state carbon 13C NMR spectroscopy reveals its well-defined single-site dual active centers. Electron microscopy investigations disclose its uniformly distributed mesoporous nanoparticles. As envisaged, this bifunctional catalyst enables a controllable aza-Michael addition/asymmetric transfer hydrogenation catalytic sequence, where the base-catalyzed aza-Michael addition of enones and amines to aryl-substituted β-secondary amino ketones is followed by a Ru-catalyzed asymmetric transfer hydrogenation. Various aryl-substituted γ-secondary amino alcohols are obtained in high yields and enantioselectivities via this one-pot enantioselective organic transformation. Furthermore, the heterogeneous catalyst can be applied in a continuous-flow process, which was shown to be particularly attractive for the practical preparation of aryl-substituted γ-secondary amino alcohols in an environmentally friendly medium.
Mannich reactions using benzyl azide as a latent N- (phenylamino)methylating agent
Schildknegt, Klaas,Agrios, Konstantinos A.,Aube, Jeffrey
, p. 7687 - 7690 (1998)
Treatment of benzyl azide with triflic acid or titanium tetrachloride effects 1,2-phenyl migration with concomitant liberation of molecular nitrogen. The resulting N-phenyl iminium ion intermediate readily combines with enolizable carbonyl substrates to f
Hydrogen-Atom-Transfer-Mediated Acceptorless Dehydrogenative Cross-Coupling Enabled by Multiple Catalytic Functions of Zwitterionic Triazolium Amidate
Minami, Kodai,Ohmatsu, Kohsuke,Ooi, Takashi
, p. 1971 - 1976 (2022/02/07)
An unconventional cooperative catalysis for hydrogen-atom-transfer-mediated acceptorless dehydrogenative cross-coupling is described. The combined use of zwitterionic 1,2,3-triazolium amidate and an Ir-based photosensitizer as catalysts enables C-H/C-H cross-couplings between heteroatom-containing C-H donors and enamides or 1,1-diarylethenes under visible-light irradiation without the need for any oxidants, hydrogen evolution catalysts, or electrodes. A key to establishing this catalysis is the susceptibility of the conjugate acid of the triazolium amidate, amide triazolium, toward single-electron reduction to complete the catalytic cycle.
I2-Promoted Intramolecular Oxidative Cyclization of Butenyl Anilines: A Facile Route to Benzo[b]azepines
An, Zhenyu,Ren, Yi,Liu, Yafeng,Yan, Rulong
supporting information, p. 2614 - 2617 (2021/08/06)
A metal-free approach for the synthesis of seven-membered N-heterocycles has been developed by the I2-promoted intramolecular cross-coupling/annulation of butenyl anilines. This cyclization reaction involves C?H activation and C?C bond formation and exhibits good functional group tolerance. A series of benzo[b]azepine derivatives are obtained in moderate to good yields.
Gold-Catalyzed Hydroamination of Propargylic Alcohols: Controlling Divergent Catalytic Reaction Pathways to Access 1,3-Amino Alcohols, 3-Hydroxyketones, or 3-Aminoketones
Laserna, Victor,Porter, Michael J.,Sheppard, Tom D.
, p. 11391 - 11406 (2019/09/30)
A versatile approach to the valorization of propargylic alcohols is reported, enabling controlled access to three different products from the same starting materials. First, a general method for the hydroamination of propargylic alcohols with anilines is described using gold catalysis to give 3-hydroxyimines with complete regioselectivity. These 3-hydroxyimines can be reduced to give 1,3-amino alcohols with high syn selectivity. Alternatively, by using a catalytic quantity of aniline, 3-hydroxyketones can be obtained in high yield directly from propargylic alcohols. Further manipulation of the reaction conditions enables the selective formation of 3-aminoketones via a rearrangement/hydroamination pathway. The utility of the new chemistry was exemplified by the one-pot synthesis of a selection of N-arylpyrrolidines and N-arylpiperidines. A mechanism for the hydroamination has been proposed on the basis of experimental studies and density functional theory calculations.
Iodine-catalyzed coupling of β-hydroxyketones with aromatic amines to form β-aminoketones and Benzo[h]quinolones
Miao, Changqing,Jiang, Liya,Ren, Lanhui,Xue, Qingxia,Yan, Fang,Shi, Weiwei,Li, Xinjian,Sheng, Jiwen,Kai, Shuangshuang
, p. 2215 - 2228 (2019/02/27)
An iodine-catalyzed coupling of β-hydroxyketones with aromatic amines to yield β-aminoketones and benzo[h]quinolones had been developed. Noble metallic catalysts, oxidants, α β-unsaturated ketone intermediates and aza-Michael addition were not involved in this coupling reaction which made it unique when compared to other reactions reported in literature. Inexpensive iodine catalyst, easy accessible raw materials, mild reaction conditions, good functional group tolerance and excellent selectivity made this coupling reaction be a practical method. This reaction can also be scaled up.
Domino Synthesis of α,β-Unsaturated γ-Lactams by Stereoselective Amination of α-Tertiary Allylic Alcohols
Xie, Jianing,Xue, Sijing,Escudero-Adán, Eduardo C.,Kleij, Arjan W.
, p. 16727 - 16731 (2018/11/23)
Tertiary allylic alcohols equipped with a carboxyl group can be smoothly aminated under ambient conditions by a conceptually new and stereoselective protocol under palladium catalysis. The in situ formed Z-configured γ-amino acid cyclizes to afford an α,β-unsaturated γ-lactam, releasing water as the only byproduct. This practical catalytic transformation highlights the use of a carboxyl group acting as an activating and stereodirecting functional group to provide a wide series of pharma-relevant building blocks. Various control reactions support the crucial role of the carboxyl group in the substrate to mediate these transformations.
A photoredox catalyzed radical-radical coupling reaction: Facile access to multi-substituted nitrogen heterocycles
Li, Weipeng,Duan, Yingqian,Zhang, Muliang,Cheng, Jian,Zhu, Chengjian
supporting information, p. 7596 - 7599 (2016/07/06)
Visible light induced photoredox catalysis is an efficient method for radical activation. Herein, we report the photoredox catalysis involving an intramolecular radical-radical coupling reaction that proceeds through a biradical intermediate. This protocol represents a new synthetic route to construct multi-substituted N-heterocycles. Four, five and six-membered N-heterocyclic structures with a quaternary carbon center are accessible under mild conditions.
Asymmetric Hydrogenation of β-Secondary Amino Ketones Catalyzed by a Ruthenocenyl Phosphino-oxazoline-ruthenium Complex (RuPHOX-Ru): The Synthesis of γ-Secondary Amino Alcohols
Wang, Jianxia,Wang, Yanzhao,Liu, Delong,Zhang, Wanbin
supporting information, p. 3262 - 3272 (2015/11/03)
A ruthenocenyl phosphino-oxazoline-ruthenium complex (RuPHOX-Ru) was applied successfully to the asymmetric hydrogenation of β-secondary amino ketones, directly affording the corresponding chiral γ-secondary amino alcohols in up to 99% yield and with 99% ee. Reaction with β-(benzylamino)-1-phenylpropan-1-one could be performed on a gram-scale with a relatively low catalyst loading (up to 2000 S/C). The resulting hydrogenated product could be used for the synthesis of synthetically useful compounds.
Deep Eutectic Solvent as a Recyclable Catalyst for Three-Component Synthesis of β-Amino Carbonyls
Keshavarzipour, Fariba,Tavakol, Hossein
, p. 1062 - 1066 (2015/02/19)
We have reported one-pot, three-component Mannich type reaction of aldehyde, amines and ketone (acetone and acetophenones), catalyzed by deep eutectic solvent (choline chloride/zinc chloride) at room temperature to give β-amino carbonyls in good yields. The catalyst could be recycled at least four times without remarkable decrease in its catalytic activity. The general method is easy, fast and environmental friendly.
