- One-Pot Transfer Hydrogenation Reductive Amination of Aldehydes and Ketones by Iridium Complexes “on Water”
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An efficient and practical one-pot transfer hydrogenation reductive amination of aldehydes and ketones with amines has been developed by using iridium complexes as catalysts and formic acid as hydrogen source in aqueous solution, providing an environmentally friendly methodology for the construction of a wide range of functionalized amine compounds in excellent yields (≈ 80 %-95 %). This effective methodology can be scaled up to gram scale with 0.1 mol-% catalyst loading and also be employed in the synthesis of medical substances such as Meclizine.
- Ouyang, Lu,Xia, Yanping,Liao, Jianhua,Luo, Renshi
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p. 6387 - 6391
(2020/09/11)
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- Reductive Amination by Photoredox Catalysis and Polarity-Matched Hydrogen Atom Transfer
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The excitation of a RuII photosensitizer in the presence of ascorbic acid leads to the reduction of iminium ions to electron-rich α-aminoalkyl radical intermediates, which are rapidly converted into reductive amination products by thiol-mediated hydrogen atom transfer (HAT). As a result, the reductive amination of carbonyl compounds with amines by photoredox catalysis proceeds in good to excellent yields and with broad substrate scope and good functional group tolerance. The three key features of this work are 1) the rapid interception of electron-rich α-aminoalkyl radical intermediates by polarity-matched HAT in a photoredox reaction, 2) the method of reductive amination by photoredox catalysis itself, and 3) the application of this new method for temporally and spatially controlled reactions on a solid support, as demonstrated by the attachment of a fluorescent dye on an activated cellulose support by photoredox-catalyzed reductive amination.
- Guo, Xingwei,Wenger, Oliver S.
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supporting information
p. 2469 - 2473
(2018/01/27)
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- Dichotomy of reductive addition of amines to cyclopropyl ketones vs pyrrolidine synthesis
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An interesting catalytic dichotomy was discovered: switching between simple ligand-free catalysts leads to fundamentally different outcomes of reductive reaction between amines and α-carbonylcyclopropanes. Whereas a rhodium catalyst leads to the tradition
- Afanasyev, Oleg I.,Tsygankov, Alexey A.,Usanov, Dmitry L.,Chusov, Denis
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supporting information
p. 5968 - 5970
(2016/11/29)
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- Silver-catalyzed alkyne activation: The surprising ligand effect
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An unexpected ligand effect was discovered in the silver(I)-catalyzed alkyne activation. For both aldehyde-alkyne-amine (A3) condensation and intermolecular alkyne hydroamination, the type B complex (P:Ag=1:1) effectively promoted the reaction, while no reaction occurred with either no ligand or excess ligands under the identical conditions.
- Su, Yijin,Lu, Mei,Dong, Boliang,Chen, Hao,Shi, Xiaodong
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supporting information
p. 692 - 696
(2014/04/03)
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- PROCESS FOR HYDROGENATING UNACTIVATED IMINES USING RUTHENIUM COMPLEXES AS CATALYSTS
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A process is provided for the hydrogenation or asymmetric hydrogenation of dialkyl, alkylalkenyl and dialkenyl imines of formula (II) to provide amines of formula (III), wherein, (i) R1 and R2 are optionally substituted cyclic, linear or branched alkyl or alkenyl; R3 is a hydrogen atom, a hydroxy radical, optionally substituted C1 to C8 cyclic, linear or branched alkyl or alkenyl, optionally substituted aryl; or (ii) R1 is alkyl or alkenyl, R2 is alkyl or alkenyl and the two are linked together or with R3 to form one or more rings; using a catalytic system comprising a base and a ruthenium complex containing (1) a diamine and (2) a diphosphine ligand or monodentate phosphine ligands in hydrogenation and asymmetric hydrogenation processes.
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Page/Page column 19
(2008/06/13)
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- Chemoselective reductive amination of aldehydes and ketones by dibutylchlorotin hydride-HMPA complex
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Reductive amination of various aldehydes and ketones has been performed effectively by pentacoordinate chloro-substituted tin hydride complex, Bu2SnClH-HMPA. The tin reagent worked particularly well for the case using weakly basic aromatic amines as starting substrates. Stoichiometric amounts of a substrate and a reducing agent were adequate for the reaction. The Sn-Cl bond in the complex plays an important role for both steps of imine formation and subsequent reduction. Highly chemoselective reduction of carbonyls could be achieved regardless of other functionalities such as halogen, carbon- carbon double bond and hydroxyl groups in the starting carbonyls and amines.
- Suwa, Toshihiro,Sugiyama, Erika,Shibata, Ikuya,Baba, Akio
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p. 789 - 800
(2007/10/03)
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