- Reusable Co-nanoparticles for general and selectiveN-alkylation of amines and ammonia with alcohols
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A general cobalt-catalyzedN-alkylation of amines with alcohols by borrowing hydrogen methodology to prepare different kinds of amines is reported. The optimal catalyst for this transformation is prepared by pyrolysis of a specific templated material, which is generatedin situby mixing cobalt salts, nitrogen ligands and colloidal silica, and subsequent removal of silica. Applying this novel Co-nanoparticle-based material, >100 primary, secondary, and tertiary amines includingN-methylamines and selected drug molecules were conveniently prepared starting from inexpensive and easily accessible alcohols and amines or ammonia.
- Beller, Matthias,Gawande, Manoj B.,Jagadeesh, Rajenahally V.,Kadam, Ravishankar G.,Li, Xinmin,Ma, Zhuang,Petr, Martin,Zbo?il, Radek,Zhou, Bei
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p. 111 - 117
(2022/01/06)
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- Phosphine-Free Well-Defined Mn(I) Complex-Catalyzed Synthesis of Amine, Imine, and 2,3-Dihydro-1 H-perimidine via Hydrogen Autotransfer or Acceptorless Dehydrogenative Coupling of Amine and Alcohol
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The application of nontoxic, earth-abundant transition metals in place of costly noble metals is a paramount goal in catalysis and is especially interesting if the air- and moisture-stable ligand scaffold is used. Herein, we report the synthesis of amines/imines directly from alcohol and amines via hydrogen autotransfer or acceptorless dehydrogenation catalyzed by well-defined phosphine-free Mn complexes. Both imines and amines can be obtained from the same set of alcohols and amines using the same catalyst, only by tuning the reaction conditions. The amount and nature of the base are found to be a highly important aspect for the observed selectivity. Both the primary and secondary amines have been employed as substrates for the N-alkylation reaction. As a highlight, we showed the chemoselective synthesis of resveratrol derivatives. Furthermore, the Mn-catalyzed dehydrogenative synthesis of structurally important 2,3-dihydro-1H-perimidines has also been demonstrated. Density functional theory calculations were also carried out to model the reaction path and to calculate the reaction profile.
- Das, Kalicharan,Mondal, Avijit,Pal, Debjyoti,Srivastava, Hemant Kumar,Srimani, Dipankar
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supporting information
p. 1815 - 1825
(2019/04/30)
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- Phosphino-amine (PN) Ligands for Rapid Catalyst Discovery in Ruthenium-Catalyzed Hydrogen-Borrowing Alkylation of Anilines: A Proof of Principle
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A general synthetic protocol for the synthesis of simple phosphino-amine (PN) ligands is described with 19 ligands being isolated in good yields. High-throughput ligand screening uncovered the success of two of these ligands for aromatic amine alkylations via ruthenium-catalyzed hydrogen borrowing reactions. The combination of N,N'-bis(diphenylphosphino)-N,N′-dimethylpropylenediamine with a ruthenium(II) source and potassium hydroxide (15 mol%) is the optimal system for selective monobenzylations of aromatic amines (method A). Over 70% isolated yields have been achieved for the formation of 14 secondary aromatic amines under mild reaction conditions (120 C and 1.05 equivalents of benzyl alcohol). On the other hand, N,N-bis(diphenylphosphino)-isopropylamine was the ligand utilized for both selective monomethylation and monoethylation reactions of aromatic amines (method B). Here the alcohol is charged as both the reaction medium and substrate and 9 examples are disclosed with all isolated yields exceeding 70%. These methods have been applied to the synthesis of important synthetic building blocks based on aminoferrocene.
- Broomfield, Lewis Marc,Wu, Yichen,Martin, Eddy,Shafir, Alexandr
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supporting information
p. 3538 - 3548
(2016/01/25)
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- Preparation of N-arylamines from 2-oxo-7-azobicyclo[4.1.0]heptanes
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A wide range of N-phenylated secondary amines were prepared directly from 2-oxo-7-azobicyclo[4.1.0]heptanes using 4-nitrobenzoic acid as acid catalyst. The intermediate enol esters could also be isolated under similar conditions. A catalytic cycle is proposed.
- Barros, M. Teresa,Dey, Suvendu S.,Maycock, Christopher D.,Rodrigues, Paula
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supporting information; experimental part
p. 6263 - 6268
(2012/08/28)
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- Acid-promoted rearrangement of arylmethyl azides: Applications toward the synthesis of N-arylmethyl arenes and polycyclic heteroaromatic compounds
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An acid-promoted Aubé-Schmidt's rearrangement of arylmethyl azides provides a useful in situ iminium ion intermediate, which can be efficiently trapped by various nucleophiles. We report here the reaction of this iminium ion with aromatic nucleophiles to
- Tummatorn, Jumreang,Thongsornkleeb, Charnsak,Ruchirawat, Somsak
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experimental part
p. 4732 - 4739
(2012/07/28)
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- Aerobic oxidation of amines catalyzed by polymer-incarcerated au nanoclusters: Effect of cluster size and cooperative functional groups in the polymer
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Aerobic oxidation reaction of amines to imines catalyzed by polymer-incarcerated Au nanoclusters (PI-Au) was developed. The effect of cluster size for this oxidation reaction was carefully examined using the same polymer support. We have succeeded in preparation of various PI-Au catalysts containing different size clusters by modification of standard preparation methods. The size of clusters and their distribution were analyzed by electron microscopy. Interestingly, catalysts containing relatively larger clusters (>5 nm) showed higher activity in aerobic oxidation of amines than catalysts containing smaller clusters (13 nm) that showed much better activity for aerobic oxidation of alcohols. In addition, novel Au nanocluster catalysts immobilized on newly prepared polymer with tertiary amine groups were developed and they showed excellent activity for aerobic oxidation of amines to imines. The relation between cluster size and catalytic activity and role of tertiary amine in polymer were discussed. These catalysts could be applied to aerobic oxidative deprotection of p-methoxybenzyl groups.
- Miyamura, Hiroyuki,Morita, Masataka,Inasaki, Takeshi,Kobayashi, Shu
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experimental part
p. 588 - 599
(2011/08/09)
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